CN107741382A - Liquid density measurement method and system based on continuous sound wave propagation - Google Patents

Abstract

The invention discloses a liquid density measurement method and a system based on continuous sound wave transmission, which are characterized in that the transmission time or the transmission phase when continuous sound waves are transmitted in the liquid fluid in a flowing state along the forward flow direction and the reverse flow direction is obtained, wherein the liquid fluid stably flows in a pipeline with a uniform flow field; and calculating the density of the liquid fluid according to the propagation time or the propagation phase when the obtained continuous sound waves propagate in the liquid fluid along the forward flow direction and the backward flow direction. The liquid density measuring method and the system based on continuous sound wave propagation comprehensively consider the flowing state of the liquid fluid in the pipeline, adopt the continuous sound wave mode, and calculate the density of the liquid fluid by obtaining the propagation time or the propagation phase when the continuous sound wave propagates in the liquid fluid along the forward flow direction and the reverse flow direction, thereby avoiding the difficulty of high-precision time measurement, and having convenient measurement and high measurement precision.

Description

Liquid density measurement method and system based on continuous sound wave propagation

technical field

The invention relates to the field of liquid density measurement, in particular to a liquid density measurement method and system based on continuous sound wave propagation.

Background technique

Fluid density measurement is widely used in metallurgy, construction, petrochemical, coal, medical, trade, national defense and scientific research and other fields. Fluid density measurement is not only related to the output and quality control of products, but also, from an economic or technical point of view, accurate fluid density measurement and testing is an essential link. In the industrial production process, the fluid density meter has become an indispensable industrial instrument for controlling and detecting fluid density, concentration, composition and mass flow rate; Lymph, etc.) fluid density measurement has become an important method of medical clinical and basic research; in commodity trading, accurate fluid density measurement is an important basis for ensuring supply and marketing and national taxation.

Vibration fluid density meters, capacitive fluid density meters, ray fluid density meters and ultrasonic fluid density meters are widely used in the field. Vibration and capacitance are low in cost and are widely used in measurement, but the measurement accuracy is not high and maintenance is more troublesome. The ray type can carry out non-contact measurement, but there are radiation hazards of ray, so it is less used. Ultrasonic fluid density meters have a wide range of applications, easy maintenance, high measurement accuracy, no harm to the human body, no contact with the measured medium, and fast response speed. However, for the existing ultrasonic liquid density measurement methods, flow In the case of the state, only the liquid density of the static fluid can be measured, and for high-precision density measurement, high-precision time measurement is required, and the measurement is difficult.

Therefore, the existing ultrasonic liquid density measurement method is difficult to measure and can only measure the liquid density of the fluid in a static state, which is a technical problem to be solved urgently.

Contents of the invention

The present invention provides a liquid density measurement method and system based on continuous sound wave propagation to solve the existing ultrasonic liquid density measurement method which is difficult to measure and can only measure the liquid density of the fluid in a static state question.

The technical scheme that the present invention adopts is as follows:

According to one aspect of the present invention, there is provided a liquid density measurement method based on continuous sound wave propagation, comprising the following steps:

Obtain the propagation time or propagation phase of the continuous sound wave in the liquid fluid in the flowing state when it propagates along the forward and countercurrent directions, where the liquid fluid flows stably in a pipe with a uniform flow field;

The density of the liquid fluid is calculated according to the propagation time or propagation phase of the acquired continuous sound wave in the liquid fluid along the forward and countercurrent directions.

Further, the step of obtaining the propagation phase of the continuous sound wave in the liquid fluid under the flowing state when propagating in the direction of forward flow and countercurrent flow includes:

Obtain the sound wave frequency when the continuous sound wave propagates in the liquid fluid;

According to the frequency of the acquired sound wave and the obtained downstream propagation time and upstream propagation time of the continuous sound wave propagating in the liquid fluid, the downstream propagation phase of the continuous sound wave propagating along the downstream direction in the liquid fluid under the flow state is obtained and the countercurrent propagation phase of a continuous sound wave propagating in the countercurrent direction in a flowing liquid fluid.

Further, the downstream propagation phase is obtained by the following formula:

φ _d ＝360°×f×t _d

Among them, φ _d is the downstream propagation phase, f is the acoustic frequency, and t _d is the downstream propagation time.

Further, the countercurrent propagation phase is obtained by the following formula:

φ _u ＝360°×f×t _u

Among them, φ _u is the countercurrent propagation phase, f is the acoustic frequency, and t _u is the countercurrent propagation time.

Further, the fluid density is calculated by the following formula:

Among them, E is the bulk elastic modulus, t _d is the travel time of the downstream, t _u is the travel time of the upstream, and L is the travel length.

Further, the fluid density is calculated by the following formula:

Among them, ρ is the fluid density, E is the bulk elastic modulus, f is the acoustic wave frequency, L is the propagation length, φ _d is the downstream propagation phase, and φ _u is the upstream propagation phase.

Further, after the step of calculating the density of the liquid fluid, the step of calculating the density of the liquid fluid also includes:

According to the propagation phase of the obtained continuous sound wave in the liquid fluid along the forward and backward directions, the forward and reverse phase difference is obtained;

According to the obtained forward and reverse flow phase difference, the instantaneous volume flow rate and the instantaneous mass flow rate of the liquid fluid are measured synchronously.

Further, the instantaneous volume flow is measured by the following formula:

Among them, Q _V is the instantaneous volume flow rate, R is the pipe radius, f is the acoustic wave frequency, L is the propagation length, φ _d is the downstream propagation phase, and φ _u is the upstream propagation phase.

Further, the instantaneous mass flow is measured by the following formula:

Q _M =ρ×Q _V

Among them, Q _M is the instantaneous volume flow rate, ρ is the fluid density, and Q _V is the instantaneous volume flow rate.

According to another aspect of the present invention, there is also provided a liquid density measurement system based on continuous sound wave propagation, comprising:

The obtaining module is used to obtain the propagation time or propagation phase of the continuous sound wave in the liquid fluid in the flowing state when it propagates along the forward and countercurrent directions, wherein the liquid fluid flows stably in a pipeline with a uniform flow field;

The first calculation module is used to calculate the density of the liquid fluid according to the acquired propagation time or propagation phase of the continuous sound wave propagating in the liquid fluid along the direction of forward flow and countercurrent flow.

Further, the acquisition module includes:

The acquisition unit is used to acquire the frequency of the sound wave when the continuous sound wave propagates in the liquid fluid;

Calculation unit for obtaining the frequency of the sound wave and the obtained downstream propagation time and upstream propagation time of the continuous sound wave propagating in the liquid fluid and the obtained downstream propagation time and upstream propagation time of the continuous sound wave propagating in the liquid fluid From the propagation time, the forward propagation phase of the continuous sound wave propagating in the downstream direction in the liquid fluid under the flowing state and the countercurrent propagation phase of the continuous sound wave propagating in the countercurrent direction in the liquid fluid under the flowing state are obtained.

Further, the liquid density measurement system based on continuous sound wave propagation also includes:

The second calculation module is used to obtain the forward and reverse flow phase difference according to the obtained propagation phase of the continuous sound wave in the liquid fluid along the forward flow and the reverse flow direction;

The measuring module is used for synchronously measuring the instantaneous volume flow and/or instantaneous mass flow of the liquid fluid according to the obtained forward and reverse flow phase difference.

The present invention has the following beneficial effects:

The liquid density measurement method and system based on continuous sound wave propagation provided by the present invention comprehensively considers the flow state of the liquid fluid existing in the pipeline, and adopts the method of continuous sound waves, and obtains continuous sound waves in the liquid fluid along the direction of downstream and reverse flow The density of the liquid fluid is calculated by the propagation time or propagation phase during propagation, which avoids the difficulty of high-precision time measurement. The liquid density measurement method and system based on continuous sound wave propagation provided by the present invention has convenient measurement and high measurement accuracy.

In addition to the objects, features and advantages described above, the present invention has other objects, features and advantages. Hereinafter, the present invention will be described in further detail with reference to the drawings.

Description of drawings

The accompanying drawings constituting a part of this application are used to provide further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is the schematic flow chart of the first preferred embodiment of the liquid density measuring method based on continuous acoustic wave propagation of the present invention;

Fig. 2 is a schematic structural view of a preferred embodiment of the ultrasonic fluid density measuring device of the present invention;

Fig. 3 is a schematic diagram of the refinement of the steps of obtaining the propagation time of the continuous sound wave in the liquid fluid under the flowing state when it propagates along the downstream and countercurrent directions in Fig. 1;

Fig. 4 is a schematic flow chart showing the refinement of the steps of obtaining the propagation phase of the continuous sound wave in the liquid fluid under the flowing state when propagating along the forward and countercurrent directions in Fig. 1;

5 is a schematic flow diagram of a second preferred embodiment of the method for measuring liquid density based on continuous acoustic wave propagation in the present invention;

Fig. 6 is the functional block diagram of the first preferred embodiment of the liquid density measurement system based on continuous acoustic wave propagation of the present invention;

Fig. 7 is a schematic structural diagram of a preferred embodiment of the acquisition module in Fig. 6;

Fig. 8 is a functional block diagram of the second preferred embodiment of the liquid density measurement system based on continuous acoustic wave propagation of the present invention.

Explanation of reference numbers:

10. Acquisition module; 20. First calculation module; 11. Acquisition unit; 12. Calculation unit; 30. Second calculation module; 40. Measurement module; 100. Pipeline; 200. First ultrasonic probe; 300. Second ultrasonic wave Probe; 110, inlet; 120, outlet; 130, fluid cavity; 131, sound wave propagation channel.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and examples.

Referring to Fig. 1, the preferred embodiment of the present invention provides a liquid density measurement method based on continuous sound wave propagation, which is applied in the ultrasonic fluid density measurement device shown in Fig. 2, the ultrasonic fluid density measurement device includes a pipeline 100, a first An ultrasonic probe 200 and a second ultrasonic probe 300, the pipeline 10 includes an inflow port 110 for injecting liquid fluid and an outflow port 120 for outputting the liquid fluid injected into the inflow port 110, and for connecting the inflow port 110 and the outflow port mouth 120 to form a fluid cavity 130 for flowing liquid fluid, the first ultrasonic probe 200 and the second ultrasonic probe 300 are placed at both ends of the fluid cavity 130 respectively, and the first ultrasonic probe 200 is arranged in the pipeline near the inlet 110 10, the second ultrasonic probe 300 is arranged at one end of the pipeline 100 near the outlet 120, and the sound wave propagation channel 131 for propagating the continuous sound waves sent by the first ultrasonic probe 200 or the second ultrasonic probe 300 is formed in the fluid chamber 130 , the method for measuring liquid density based on continuous acoustic wave propagation provided in this embodiment includes the following steps:

Step S100, obtaining the propagation time or propagation phase of the continuous sound wave when propagating in the forward and reverse directions in the liquid fluid under the flowing state, wherein the liquid fluid flows stably in a pipeline with a uniform flow field.

In this embodiment, referring to FIG. 2 , the liquid fluid is input from the inlet 110 of the pipeline 100 , flows through the fluid chamber 130 of the pipeline 100 , and is output from the outlet 120 of the pipeline 100 to form a flowing liquid fluid. Wherein, when the continuous sound wave emitted by the first ultrasonic probe 20 propagates to the second ultrasonic probe 30 through the sound wave propagation channel 131 , it propagates in a downstream direction. When the continuous sound wave emitted by the second ultrasonic probe 30 propagates to the first ultrasonic probe 200 through the sound wave propagation channel 131 , it propagates in the countercurrent direction. Obtain the downstream propagation velocity when the continuous sound wave propagates in the downstream direction, the upstream propagation velocity when the continuous sound wave propagates in the upstream direction, and the static flow propagation velocity when the continuous sound wave propagates in the liquid fluid at rest. The downstream travel time is calculated from the downstream propagation velocity and the static flow propagation velocity. The countercurrent propagation time is calculated from the countercurrent propagation velocity and the static flow propagation velocity. For a continuous sound wave with a set frequency, according to the calculated downstream propagation time, the downstream propagation phase of the continuous sound wave propagating in the downstream direction in the flowing liquid fluid is obtained; according to the calculated upstream propagation time, the The countercurrent propagation phase of the continuous sound wave propagating in the countercurrent direction in the liquid fluid under the flowing state.

Step S200 , calculating the density of the liquid fluid according to the acquired propagation time or propagation phase of the continuous sound wave propagating in the liquid fluid in the direction of forward flow and countercurrent flow.

The density of the liquid fluid is calculated according to the obtained forward propagation time of the continuous sound wave propagating in the liquid fluid along the downstream direction and the countercurrent propagation time of the continuous sound wave propagating in the liquid fluid along the countercurrent direction. Alternatively, the density of the liquid fluid can be calculated according to the acquired forward propagation phase of the continuous sound wave propagating in the forward direction in the liquid fluid and the countercurrent propagation phase of the continuous sound wave propagating in the countercurrent direction in the liquid fluid.

The liquid density measurement method based on continuous sound wave propagation provided in this embodiment comprehensively considers the flow state of the liquid fluid existing in the pipeline, and adopts the method of continuous sound waves to propagate in the liquid fluid along the downstream and countercurrent directions by acquiring continuous sound waves The density of the liquid fluid can be calculated by the propagation time or the propagation phase of time, which avoids the difficulty of high-precision time measurement. The liquid density measurement method based on continuous sound wave propagation provided by the present invention is convenient for measurement and has high measurement accuracy.

Preferably, as shown in FIG. 3, the liquid density measurement method based on continuous sound wave propagation provided by this embodiment, step S100 includes:

Step S110, obtaining the static flow propagation velocity when the continuous sound wave propagates in the liquid fluid in a static state.

Use the following formula to calculate the static flow propagation velocity of a continuous sound wave propagating in a liquid fluid at rest:

Among them, c is the static flow propagation velocity, L is the propagation length, and _t0 is the sound wave propagation time in the static fluid.

Step S120 , acquiring the forward propagation velocity when the continuous sound wave propagates in the forward direction and the upstream propagation velocity when the continuous sound wave propagates in the countercurrent direction in the liquid fluid under the flowing state.

Use the flow velocity measuring instrument to obtain the flow velocity of the liquid fluid, and according to the calculated static flow propagation velocity when the continuous sound wave propagates in the liquid fluid in the static state, the velocity when the continuous sound wave propagates along the flow in the liquid fluid in the flowing state is obtained Downstream propagation velocity and countercurrent propagation velocity when propagating in the upstream direction. Among them, the downstream propagation velocity is the sum of the static flow propagation velocity and the liquid fluid flow velocity. The countercurrent propagation velocity is the difference between the static flow propagation velocity and the liquid fluid flow velocity.

Step S130 , according to the acquired static flow propagation velocity and downstream propagation velocity, obtain the downstream propagation time of the continuous sound wave when propagating in the stable flowing uniform liquid fluid.

According to the static flow propagation velocity of the continuous sound wave propagating in the liquid fluid in the static state and the downstream propagation velocity of the continuous sound wave in the liquid fluid in the flowing state, the continuous sound wave in the steady flow is calculated The downstream travel time when propagating in a homogeneous liquid fluid.

The downstream travel time is calculated by the following formula:

Among them, t _d is the travel time along the current flow, L is the propagation length, c is the static flow propagation velocity, and u is the flow velocity of the liquid fluid.

Step S140 , according to the obtained static flow propagation velocity and reverse flow propagation velocity, obtain the reverse flow propagation time when the continuous sound wave propagates in the stable flowing uniform liquid fluid.

According to the static flow propagation velocity of the continuous sound wave propagating in the liquid fluid in the static state and the countercurrent propagation velocity of the continuous sound wave propagating in the countercurrent direction in the liquid fluid in the flowing state, the continuous sound wave in the steady flow is calculated Countercurrent propagation time when propagating in a homogeneous liquid fluid.

The countercurrent travel time is calculated by the following formula:

Among them, t _u is the countercurrent propagation time, L is the propagation length, c is the static flow propagation velocity, and u is the liquid fluid velocity.

In this case, there are:

Introduce the average Mach number M=u/c, then:

Substituting formula (5) into formula (1), we can get:

For liquid fluid measurement, the flow velocity of liquid fluid is much smaller than the propagation velocity of sound waves, that is, there is M ² <<1 (take the pipeline water flow of 10m/s as an example, M ² =0.0000444), then:

Among them, E is the bulk elastic modulus, t _d is the travel time of the downstream, t _u is the travel time of the upstream, and L is the travel length.

It should be pointed out that under the assumption that the time measurement accuracy is the same in the forward and reverse directions, the following conclusions exist:

The liquid density measurement method based on continuous sound wave propagation provided in this embodiment obtains the static flow propagation velocity when the continuous sound wave propagates in the liquid fluid in the static state; obtains the continuous sound wave propagating along the flow in the liquid fluid in the flowing state The forward propagation velocity of the time and the countercurrent propagation velocity of the countercurrent direction; according to the static flow propagation velocity and the downstream propagation velocity obtained, the downstream propagation time of the continuous sound wave propagating in the stable flowing uniform liquid fluid is obtained; according to the acquired The static flow propagation velocity and the countercurrent propagation velocity of , get the countercurrent propagation time when the continuous sound wave propagates in the steady flowing uniform liquid fluid. The liquid density measurement method based on continuous sound wave propagation provided in this embodiment comprehensively considers the flow state of the liquid fluid existing in the pipeline, and adopts the method of continuous sound waves to propagate in the liquid fluid along the downstream and countercurrent directions by acquiring continuous sound waves The density of the liquid fluid can be calculated by the time propagation time, which avoids the difficulty of high-precision time measurement, and the measurement is convenient and the measurement accuracy is high.

Preferably, as shown in FIG. 4, the liquid density measurement method based on continuous sound wave propagation provided by this embodiment, step S100 also includes:

Step S150, acquiring the frequency of the sound wave when the continuous sound wave propagates in the liquid fluid.

Obtain the frequency of the sound wave when the continuous sound wave emitted by the first ultrasonic probe 200 propagates along the direction of flow in the liquid fluid under the flowing state and the frequency of the sound wave when the continuous sound wave emitted by the second ultrasonic probe 300 propagates along the direction of the reverse flow in the liquid fluid under the flowing state sound wave frequency. For the convenience of measurement, in this embodiment, the frequency of the continuous sound waves emitted by the first ultrasonic probe 200 and the second ultrasonic probe 300 is the same.

Step S160, according to the obtained frequency of the sound wave and the obtained forward and backward propagation time of the continuous sound wave propagating in the liquid fluid, obtain the forward flow time of the continuous sound wave propagating in the liquid fluid in the flowing state along the forward direction. Flow propagation phase and countercurrent propagation phase of a continuous acoustic wave propagating in the countercurrent direction in a liquid fluid in a flowing state.

According to the acquired frequency of the continuous sound wave emitted by the first ultrasonic probe 200 when it propagates in the liquid fluid in the flowing state along the downstream direction, calculate the forward frequency of the continuous sound wave when it propagates in the liquid fluid in the flowing state in the downstream direction. Flow propagation phase.

The downstream propagation phase is given by the following formula:

φ _d ＝360°×f×t _d (9)

Among them, φ _d is the downstream propagation phase, f is the acoustic frequency, and t _d is the downstream propagation time.

According to the acquired frequency of the continuous sound wave emitted by the second ultrasonic probe 300 when propagating in the countercurrent direction in the liquid fluid in the flowing state, calculate the countercurrent propagation phase when the continuous sound wave propagates in the countercurrent direction in the liquid fluid in the flowing state .

The countercurrent propagation phase is given by the following formula:

φ _u ＝360°×f×t _u (10)

Among them, φ _u is the countercurrent propagation phase, f is the acoustic frequency, and t _u is the countercurrent propagation time.

Fluid density is calculated from the following formula:

Among them, ρ is the fluid density, E is the bulk elastic modulus, f is the acoustic wave frequency, L is the propagation length, φ _d is the downstream propagation phase, and φ _u is the upstream propagation phase.

At the same time, if the phase measurement accuracy is the same along the downstream and upstream directions, then there is

Taking the above assumptions as an example, the temperature is 293K, at this time c=1481.9m/s in pure water, assuming that the propagation length L=0.2m, the sound wave frequency is 5MHz, and the pipeline velocity u=10m/s, then φ _d =241303°, φ _u = 244581.8°. If the absolute error of the measured density is to be less than 100g/m ³ , then:

Δφ _d <12.09°, Δφ _u <12.25° (13)

The liquid density measurement method based on continuous sound wave propagation provided in this embodiment obtains the sound wave frequency when the continuous sound wave propagates in the liquid fluid; Time and countercurrent propagation time, the forward propagation phase of the continuous sound wave propagating in the downstream direction in the liquid fluid under the flowing state and the countercurrent propagation phase of the continuous sound wave propagating in the countercurrent direction in the liquid fluid under the flowing state. The liquid density measurement method based on continuous sound wave propagation provided in this embodiment comprehensively considers the flow state of the liquid fluid existing in the pipeline, and adopts the method of continuous sound waves to propagate in the liquid fluid along the downstream and countercurrent directions by acquiring continuous sound waves The density of the liquid fluid can be calculated by the propagation phase of the time, which avoids the difficulty of high-precision time measurement, and the measurement is convenient and the measurement accuracy is high.

Preferably, as shown in Figure 5, Figure 5 is a schematic flow chart of the second preferred embodiment of the method for measuring liquid density based on continuous sound wave propagation in the present invention. On the basis of the first embodiment, this embodiment provides a method based on continuous sound wave propagation The method for measuring liquid density, after step S200, also includes:

Step S300 , according to the acquired propagation phases of the continuous sound waves in the liquid fluid in the forward and reverse directions, obtain the forward and reverse phase difference.

According to the calculation of the downstream propagation phase of the continuous sound wave propagating along the downstream direction in the liquid fluid under the flowing state and the countercurrent propagation phase of the continuous sound wave propagating along the countercurrent direction in the liquid fluid under the flowing state, it is obtained by subtraction Phase difference between forward and reverse flow.

Step S400, synchronously measure the instantaneous volume flow rate and instantaneous mass flow rate of the liquid fluid according to the obtained forward and reverse flow phase difference.

According to formulas (2), (3) and (5), the forward and reverse time difference is obtained:

Among them, t _u is the upstream propagation time, t _d is the downstream propagation time, L is the propagation length, u is the liquid fluid flow velocity, and c is the static flow propagation velocity.

According to formulas (9), (10) and (5), the forward and reverse phase difference is obtained:

Among them, φ _u is the upstream propagation phase, φ _d is the downstream propagation phase, f is the acoustic wave frequency, L is the propagation length, u is the liquid fluid flow velocity, and c is the static flow propagation velocity.

Then according to formulas (14) and (15), we can get:

Substituting formula (5) into formula (16), we have

The instantaneous volume flow is measured by the following formula:

Among them, Q _V is the instantaneous volume flow rate, R is the pipe radius, f is the acoustic wave frequency, L is the propagation length, φ _d is the downstream propagation phase, and φ _u is the upstream propagation phase.

Preferably, the instantaneous mass flow rate is measured by the following formula:

Among them, Q _M is the instantaneous volume flow rate, ρ is the fluid density, and Q _V is the instantaneous volume flow rate.

The liquid density measurement method based on continuous sound wave propagation provided in this embodiment obtains the forward and reverse flow phase difference according to the acquired continuous sound wave propagation phases in the liquid fluid along the forward and reverse flow directions; according to the obtained forward and reverse flow phase difference, and simultaneously measure the instantaneous volume flow and instantaneous mass flow of liquid fluid. The liquid density measurement method based on continuous sound wave propagation provided in this embodiment can simultaneously measure volume flow and mass flow, avoiding the difficulty of high-precision time measurement, and the measurement is convenient and has high measurement accuracy.

As shown in Figure 6, this embodiment also provides a liquid density measurement system based on continuous sound wave propagation, which is applied to the ultrasonic fluid density measurement device shown in Figure 2, the ultrasonic fluid density measurement device includes a pipeline 100, a first The ultrasonic probe 200 and the second ultrasonic probe 300, the pipeline 10 includes an inflow port 110 for injecting liquid fluid and an outflow port 120 for outputting the liquid fluid injected into the inflow port 110, and for connecting the inflow port 110 and the outflow port 120 to form a fluid cavity 130 for flowing liquid fluid, the first ultrasonic probe 200 and the second ultrasonic probe 300 are respectively placed at both ends of the fluid cavity 130, and the first ultrasonic probe 200 is arranged in the pipeline 10 near the inlet 110 The second ultrasonic probe 300 is arranged at one end of the pipeline 100 close to the outlet 120, and the sound wave propagation channel 131 for propagating the continuous sound waves emitted by the first ultrasonic probe 200 or the second ultrasonic probe 300 is formed in the fluid cavity 130, This embodiment also provides a liquid density measurement system based on continuous sound wave propagation, including an acquisition module 10 and a first calculation module 20, and the acquisition module 10 is used to acquire continuous sound waves in a liquid fluid in a flowing state along the forward flow and reverse flow Propagation time or propagation phase during directional propagation, wherein the liquid fluid flows stably in a pipeline with a uniform flow field; the first calculation module 20 is used to propagate in the liquid fluid along the forward and countercurrent directions according to the acquired continuous sound wave The propagation time or propagation phase of , calculate the density of the liquid fluid.

In this embodiment, referring to FIG. 2 , the liquid fluid is input from the inlet 110 of the pipeline 100 , flows through the fluid chamber 130 of the pipeline 100 , and is output from the outlet 120 of the pipeline 100 to form a flowing liquid fluid. Wherein, when the continuous sound wave emitted by the first ultrasonic probe 200 propagates to the second ultrasonic probe 300 through the sound wave propagation channel 131 , it propagates in a downstream direction. When the continuous sound wave emitted by the second ultrasonic probe 30 propagates to the first ultrasonic probe 200 through the sound wave propagation channel 131 , it propagates in the countercurrent direction. The acquisition module 10 acquires the forward propagation velocity when the continuous sound wave propagates in the downstream direction, the countercurrent propagation velocity when the continuous sound wave propagates in the countercurrent direction, and the static flow propagation velocity when the continuous sound wave propagates in the liquid fluid in a static state. The downstream travel time is calculated from the downstream propagation velocity and the static flow propagation velocity. The countercurrent propagation time is calculated from the countercurrent propagation velocity and the static flow propagation velocity. For a continuous sound wave with a set frequency, according to the calculated downstream propagation time, the downstream propagation phase of the continuous sound wave propagating in the downstream direction in the liquid fluid under the flow state is obtained; according to the calculated upstream propagation time, the The countercurrent propagation phase of the continuous sound wave propagating in the countercurrent direction in the liquid fluid under the flowing state.

The first calculation module 20 calculates the density of the liquid fluid according to the obtained forward propagation time of the continuous sound wave propagating in the liquid fluid along the downstream direction and the countercurrent propagation time of the continuous sound wave propagating in the liquid fluid in the countercurrent direction. Alternatively, the density of the liquid fluid can be calculated according to the acquired forward propagation phase of the continuous sound wave propagating in the forward direction in the liquid fluid and the countercurrent propagation phase of the continuous sound wave propagating in the countercurrent direction in the liquid fluid.

The liquid density measurement system based on continuous sound wave propagation provided in this embodiment comprehensively considers the flow state of the liquid fluid existing in the pipeline, and adopts the continuous sound wave method to propagate in the liquid fluid along the downstream and countercurrent directions by acquiring continuous sound waves The density of the liquid fluid can be calculated by the propagation time or propagation phase of time, which avoids the difficulty of high-precision time measurement. The liquid density measurement system based on continuous sound wave propagation provided by the present invention is convenient for measurement and has high measurement accuracy.

Preferably, as shown in FIG. 7 , in the liquid density measurement system based on continuous sound wave propagation provided by this embodiment, the acquisition module 10 includes an acquisition unit 11 and a calculation unit 12, and the acquisition unit 11 is used to acquire the continuous sound wave propagation in the liquid fluid Acoustic wave frequency at time; calculation unit 12, be used for according to the acoustic wave frequency that obtains and obtain continuous acoustic wave when propagating in the liquid fluid and the forward flow propagation time and countercurrent propagation time, obtain the continuous acoustic wave in the liquid fluid under the flowing state The downstream propagation phase when propagating in the downstream direction and the countercurrent propagation phase when the continuous sound wave propagates in the upstream direction in the liquid fluid under flow state.

The acquisition unit 11 acquires the frequency of the continuous sound waves emitted by the first ultrasonic probe 200 when propagating in the downstream direction in the liquid fluid under the flow state and the frequency of the continuous sound waves emitted by the second ultrasonic probe 300 along the counter-flow direction in the liquid fluid under the flow state. The frequency of sound waves as they propagate in one direction. For the convenience of measurement, in this embodiment, the frequency of the continuous sound waves emitted by the first ultrasonic probe 200 and the second ultrasonic probe 300 is the same.

The calculation unit 12 calculates that the continuous sound wave propagates along the downstream direction in the liquid fluid under the flowing state according to the obtained frequency of the continuous sound wave emitted by the first ultrasonic probe 200 propagating in the downstream direction in the liquid fluid under the flowing state. The downstream propagation phase of .

The downstream propagation phase is given by the following formula:

φ _d ＝360°×f×t _d (20)

Among them, φ _d is the downstream propagation phase, f is the acoustic frequency, and t _d is the downstream propagation time.

According to the acquired frequency of the continuous sound wave emitted by the second ultrasonic probe 300 when propagating in the countercurrent direction in the liquid fluid in the flowing state, calculate the countercurrent propagation phase when the continuous sound wave propagates in the countercurrent direction in the liquid fluid in the flowing state .

The countercurrent propagation phase is given by the following formula:

φ _u ＝360°×f×t _u (21)

Among them, φ _u is the countercurrent propagation phase, f is the acoustic frequency, and t _u is the countercurrent propagation time.

Fluid density is calculated from the following formula:

Among them, ρ is the fluid density, E is the bulk elastic modulus, f is the acoustic wave frequency, L is the propagation length, φ _d is the downstream propagation phase, and φ _u is the upstream propagation phase.

At the same time, if the phase measurement accuracy is the same along the downstream and upstream directions, then there is

Taking the above assumptions as an example, the temperature is 293K, at this time c=1481.9m/s in pure water, assuming that the propagation length L=0.2m, the sound wave frequency is 5MHz, and the pipeline velocity u=10m/s, then φ _d =241303°, φ _u = 244581.8°. If the absolute error of the measured density is to be less than 100g/m ³ , then:

Δφ _d <12.09°, Δφ _u <12.25° (24)

The liquid density measurement system based on continuous sound wave propagation provided in this embodiment obtains the frequency of the sound wave when the continuous sound wave propagates in the liquid fluid; Time and countercurrent propagation time, the forward propagation phase of the continuous sound wave propagating in the downstream direction in the liquid fluid under the flowing state and the countercurrent propagation phase of the continuous sound wave propagating in the countercurrent direction in the liquid fluid under the flowing state. The liquid density measurement system based on continuous sound wave propagation provided in this embodiment comprehensively considers the flow state of the liquid fluid existing in the pipeline, and adopts the continuous sound wave method to propagate in the liquid fluid along the downstream and countercurrent directions by acquiring continuous sound waves The density of the liquid fluid can be calculated by the propagation phase of the time, which avoids the difficulty of high-precision time measurement, and the measurement is convenient and the measurement accuracy is high.

Preferably, as shown in Figure 8, Figure 8 is a functional block diagram of the second preferred embodiment of the liquid density measurement system based on continuous sound wave propagation in the present invention. On the basis of the first embodiment, this embodiment provides a continuous sound wave propagation based The liquid density measurement system also includes a second calculation module 30 and a measurement module 40, and the second calculation module 30 is used to obtain the forward and backward directions according to the propagation phases of the acquired continuous sound waves in the liquid fluid along the forward flow and countercurrent directions. Countercurrent phase difference; the measurement module 40 is used to measure the instantaneous volume flow and/or instantaneous mass flow of the liquid fluid synchronously according to the obtained forward and reverse flow phase difference.

The second calculation module 30 calculates the downstream propagation phase when the continuous sound wave propagates along the downstream direction in the liquid fluid under the flowing state and the countercurrent propagation phase when the continuous sound wave propagates along the upstream direction in the liquid fluid under the flowing state, The forward and reverse phase difference is obtained by subtraction.

According to formulas (2), (3) and (5), the forward and reverse time difference is obtained:

Among them, t _u is the upstream propagation time, t _d is the downstream propagation time, L is the propagation length, u is the liquid fluid flow velocity, and c is the static flow propagation velocity.

According to formulas (20), (21) and (5), the phase difference between forward and reverse flow is obtained:

Among them, φ _u is the upstream propagation phase, φ _d is the downstream propagation phase, f is the acoustic wave frequency, L is the propagation length, u is the liquid fluid flow velocity, and c is the static flow propagation velocity.

Measurement module 40 can draw according to formula (25) and (26):

Substituting formula (5) into formula (27), we have

The instantaneous volume flow is measured by the following formula:

Among them, Q _V is the instantaneous volume flow rate, R is the pipe radius, f is the acoustic wave frequency, L is the propagation length, φ _d is the downstream propagation phase, and φ _u is the upstream propagation phase.

The instantaneous mass flow rate is measured by the following formula:

Among them, Q _M is the instantaneous volume flow rate, ρ is the fluid density, and Q _V is the instantaneous volume flow rate.

The liquid density measurement system based on continuous sound wave propagation provided in this embodiment obtains the forward and reverse flow phase difference according to the acquired continuous sound wave propagation phases in the liquid fluid along the forward and reverse flow directions; according to the obtained forward and reverse flow phase difference, and simultaneously measure the instantaneous volume flow and instantaneous mass flow of liquid fluid. The liquid density measurement system based on continuous sound wave propagation provided in this embodiment can simultaneously measure volume flow and mass flow, avoid the difficulty of high-precision time measurement, and have convenient measurement and high measurement accuracy.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A liquid density measurement method based on continuous sound wave propagation, is characterized in that, comprises the following steps: Obtaining the propagation time or propagation phase of the continuous sound wave in the liquid fluid under the flowing state when propagating in the direction of forward flow and countercurrent flow, wherein the liquid fluid flows stably in a pipeline with a uniform flow field; The density of the liquid fluid is calculated according to the acquired propagation time or propagation phase of the continuous sound wave propagating in the liquid fluid in the direction of forward flow and countercurrent flow. 2. the liquid density measuring method based on continuous acoustic wave propagation according to claim 1, is characterized in that, The step of obtaining the propagation phase of the continuous sound wave in the liquid fluid under the flowing state when propagating in the direction of forward flow and countercurrent flow includes: Acquiring the frequency of the sound wave when the continuous sound wave propagates in the liquid fluid; According to the acquired frequency of the sound wave and the obtained downstream propagation time and countercurrent propagation time of the continuous sound wave propagating in the liquid fluid, it can be concluded that the continuous sound wave propagates along the downstream direction in the liquid fluid in a flowing state The forward-current propagation phase at time and the counter-current propagation phase when the continuous sound wave propagates in the counter-current direction in the liquid fluid under the flowing state. 3. the liquid density measuring method based on continuous acoustic wave propagation according to claim 2, is characterized in that, The downstream propagation phase is given by the following formula: φ _d ＝360°×f×t _d The countercurrent propagation phase is given by the following formula: φ _u ＝360°×f×t _u Among them, φ _d is the downstream propagation phase, f is the acoustic frequency, t _d is the downstream propagation time, φ _u is the upstream propagation phase, and t _u is the upstream propagation time. 4. the liquid density measuring method based on continuous acoustic wave propagation according to claim 1, is characterized in that, The fluid density is calculated by the following formula: <mrow><mi>&amp;rho;</mi><mo>&amp;ap;</mo><mfrac><mrow><mi>E</mi><mo>&amp;times;</mo><msub><mi>t</mi><mi>d</mi></msub><mo>&amp;times;</mo><msub><mi>t</mi><mi>u</mi></msub></mrow><msup><mi>L</mi><mn>2</mn></msup></mfrac></mrow> Among them, E is the bulk elastic modulus, t _d is the travel time of the downstream, t _u is the travel time of the upstream, and L is the travel length. 5. the liquid density measuring method based on continuous acoustic wave propagation according to claim 1, is characterized in that, The fluid density is calculated by the following formula: Among them, ρ is the fluid density, E is the bulk elastic modulus, f is the acoustic wave frequency, L is the propagation length, φ _d is the downstream propagation phase, and φ _u is the upstream propagation phase. 6. the liquid density measuring method based on continuous acoustic wave propagation according to claim 1, is characterized in that, After the step of calculating the density of the liquid fluid based on the acquired propagation phases of the continuous sound waves propagating in the liquid fluid along the forward and countercurrent directions, the step further includes: According to the acquired propagation phases of the continuous sound wave in the liquid fluid along the forward and backward directions, the phase difference between forward and reverse flow is obtained; The instantaneous volume flow and/or instantaneous mass flow of the liquid fluid are measured synchronously according to the obtained forward and reverse flow phase difference. 7. the liquid density measuring method based on continuous acoustic wave propagation according to claim 6, is characterized in that, The instantaneous volume flow is measured by the following formula: <mrow><msub><mi>Q</mi><mi>V</mi></msub><mo>=</mo><mn>180</mn><mo>&amp;times;</mo><mi>&amp;pi;</mi><mo>&amp;times;</mo><msup><mi>R</mi><mn>2</mn></msup><mo>&amp;times;</mo><mi>f</mi><mo>&amp;times;</mo><mi>L</mi><mo>&amp;times;</mo><mfrac><mrow><mo>(</mo><msub><mi>&amp;phi;</mi><mi>u</mi></msub><mo>-</mo><msub><mi>&amp;phi;</mi><mi>d</mi></msub><mo>)</mo></mrow><mrow><msub><mi>&amp;phi;</mi><mi>u</mi></msub><mo>&amp;times;</mo><msub><mi>&amp;phi;</mi><mi>d</mi></msub></mrow></mfrac></mrow> The instantaneous mass flow is measured by the following formula: Q _M =ρ×Q _V Among them, Q _V is the instantaneous volume flow rate, R is the pipe radius, f is the acoustic frequency, L is the propagation length, φ _d is the downstream propagation phase, φ _u is the upstream propagation phase, Q _M is the instantaneous volume flow rate, and ρ is the fluid density . 8. A liquid density measurement system based on continuous sound wave propagation, characterized in that, comprising: An acquisition module (10), configured to acquire the propagation time or propagation phase of the continuous sound wave in the liquid fluid under the flowing state when it propagates in the direction of forward flow and countercurrent flow, wherein the liquid fluid flows stably in a pipeline with a uniform flow field ; A first calculation module (20), configured to calculate the density of the liquid fluid according to the acquired propagation time or propagation phase of the continuous sound wave propagating in the liquid fluid in the direction of forward flow and countercurrent flow. 9. The liquid density measurement system based on continuous acoustic wave propagation according to claim 8, characterized in that, The acquisition module (10) includes: An acquisition unit (11), configured to acquire the frequency of the sound wave when the continuous sound wave propagates in the liquid fluid; A calculation unit (12), configured to obtain the frequency of the continuous sound wave in a flowing state according to the obtained frequency of the sound wave and the obtained forward and reverse flow propagation times of the continuous sound wave propagating in the liquid fluid. A forward propagation phase when propagating in a forward direction in the liquid fluid and a countercurrent propagation phase when the continuous sound wave propagates in a countercurrent direction in the liquid fluid in a flowing state. 10. The liquid density measurement system based on continuous acoustic wave propagation according to claim 8, further comprising: The second calculating module (30), is used for obtaining the forward and backward phase phase difference according to the acquired propagation phases of the continuous sound wave in the liquid fluid along the forward and backward directions; The measuring module (40) is used for synchronously measuring the instantaneous volume flow rate and/or the instantaneous mass flow rate of the liquid fluid according to the obtained phase difference between forward and reverse flow.