CN108562341A - A kind of reflective multichannel ultrasonic gas flowmeter runner - Google Patents

Abstract

The invention provides a reflective multi-channel ultrasonic gas flowmeter flow path, which includes a straight-through pipe, and the straight-through pipe is provided with an inlet end and an outlet end; A gas rectification structure is provided on the side near the inlet end; the gas rectification structure includes an air flow channel with a honeycomb structure in cross section, and the air flow channel is parallel to the axial direction of the straight-through pipe as a whole. The beneficial effect of the present invention is that: on the one hand, shorter straight-through pipes can be applied to reduce the occupied volume of the flow channel of the gas flowmeter; on the other hand, the ultrasonic measurement is more stable and accurate.

Description

Flow channel of a reflective multi-channel ultrasonic gas flowmeter

technical field

The invention relates to the technical field of gas metering devices, in particular to the structural optimization of gas flowmeters.

Background technique

The basic principle of the existing reflective ultrasonic gas flowmeter is the time difference method. The ultrasonic sensor installed on the flow channel wall and the direction of the gas flow at a certain angle measures the ultrasonic signal. The forward flow time td and the reverse flow time propagated between the ultrasonic sensors tu, the airflow velocity information V(Δt) can be obtained through the difference Δt between the forward flow time and the reverse flow time, but the applicant found through research that due to the turbulence of the airflow in the gas flowmeter, the forward flow measured by the ultrasonic sensor There is a certain error or fluctuation in the difference between the time and the reverse flow time, which in turn affects the overall measurement accuracy of the gas flow.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a reflective multi-channel ultrasonic gas flowmeter flow channel, which aims to solve the measurement accuracy error caused by gas disturbance.

To achieve the above object, the present invention adopts the following technical solutions:

A reflective multi-channel ultrasonic gas flowmeter flow channel includes a straight-through pipe, the straight-through pipe is provided with an inlet end and an outlet end; a number of ultrasonic transducer groups are arranged on the straight-through pipe, and the straight-through pipe is close to the inlet end. A gas rectification structure is provided on the side; the gas rectification structure includes an air flow channel with a honeycomb structure in cross section, and the air flow channel is generally parallel to the axial direction of the straight-through pipe.

Further, the inlet end of the straight-through pipe is provided with a guide ring, the guide ring is generally tapered or trumpet-shaped, and the cross-section of the guide ring is streamlined.

The front end of the flow channel is equipped with a guide ring and a gas rectification structure, so that the anisotropic chaotic flow at the front end of the flow channel is rectified into an effective flow parallel to the axial direction of the flow channel, which can rectify the fluid with a larger Reynolds number at the front end, and the gas rectification The laminar flow wake at the back end of the structure is small, and it is easier to eliminate it in a shorter straight pipe section. On the one hand, it can be applied to a shorter straight pipe, reducing the occupied volume of the flow channel of the gas flowmeter, and on the other hand, it also makes the ultrasonic measurement more stable and accurate. .

Description of drawings

Fig. 1 is the structural representation of embodiment.

Fig. 2 is a schematic cross-sectional view of the embodiment.

Detailed ways

The technical solutions in the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

A reflective multi-channel ultrasonic gas flowmeter flow channel, as shown in Figure 1, includes a straight-through pipeline 1, and the straight-through pipeline 1 is provided with an inlet end and an outlet end; a number of ultrasonic transducers are arranged on the straight-through pipeline 1 group, and a temperature sensor and a pressure sensor are also provided; the inlet end of the straight pipe 1 is provided with a guide ring 2, and the guide ring 2 is in the shape of a cone or a trumpet as a whole, and the inner wall of the longitudinal section of the guide ring 2 It is streamlined, which can effectively reduce the pressure loss of the gas when the caliber becomes smaller, and maintain a steady flow state of the fluid; a gas rectification structure 3 is provided on the side of the straight-through pipeline 1 near the inlet end; the gas rectification structure 3 includes a cross-section of The airflow channel of the honeycomb structure, the airflow channel is parallel to the axial direction of the straight-through pipe; the honeycomb cell section in the honeycomb structure of the gas channel includes one or more of hexagonal, quadrilateral, pentagonal, and triangular, and The gas rectification structure 3 is adapted to the shape design of the inner section of the straight-through pipe 1; the outer edge of the gas rectification structure 3 and the inner diameter of the straight-through pipe are connected by an interference fit, which can be designed according to the flow channel structure of the existing gas flowmeter The matching gas rectification structure 3 is installed to improve the turbulence effect of the existing gas flowmeter.

The gas rectification structure 3 satisfies L≥10D _H ; where L is the length of the gas rectification structure 3, and D _H is the hydraulic diameter of the honeycomb cell in the honeycomb structure of the air flow channel, and is the characteristic length of the non-circular pipe flow; thus effectively The turbulent airflow is rectified into a smooth straight-through airflow; the hydraulic diameter D _H of the honeycomb cell = 4A/P, where A is the flow area of the honeycomb cell, and P is the wetted periphery of the honeycomb cell; the gas The rectification structure needs to satisfy: d≥50a, where d is the diameter of the inscribed circle of the honeycomb cell in the honeycomb structure of the air flow channel, and a is the wall thickness of the side wall of the honeycomb cell. Based on this design, the air flow channel is honeycomb The cell not only has a small side wall thickness, but also has a small throttling effect on the pipeline and a small pressure loss; the diameter d of the inscribed circle of the honeycomb cell in the honeycomb structure described in the airflow channel satisfies 0.077D≤d≤0.173D, where D is The diameter of the flow channel can achieve a better rectification effect and eliminate the influence of the wall thickness of the honeycomb cell on the flow field at the outlet of the rectifier.

In summary, through the design of the guide ring 2 and the gas rectification structure 3, the anisotropic chaotic flow at the front end of the flow channel is rectified into an effective flow parallel to the axial direction of the flow channel, and the fluid with a larger Reynolds number at the front end can be rectified , and the rectification effect is good. The laminar flow wake at the rear end of the rectifier is small, which is easier to eliminate in the shorter straight pipe section, and the straight pipe section at the rear end of the rectifier requires less.

The number of the ultrasonic transducer groups is not less than two, and the projection angle of at least two groups of ultrasonic transducer groups on the flow channel cross section is between 30° and 90°. As shown in Fig. 1 and Fig. 2, in the present embodiment, the quantity of ultrasonic transducer groups is two, and the ultrasonic transducers in the ultrasonic transducer groups are all ultrasonic transmitting-ultrasonic receiving integrated transducers, respectively Including the first ultrasonic transducer 401 and the second ultrasonic transducer 402 of the first ultrasonic transducer group, and the third ultrasonic transducer 403 and the fourth ultrasonic transducer 404 of the second ultrasonic transducer group; The two ultrasonic transducers in any ultrasonic transducer group are installed on the straight-through pipe at a V-shaped angle, and the angle θ of the V-shaped angle is 40°-90°, so that the volume of the flowmeter can be reduced. In this case, the effective sound path is increased. The inner wall of the straight-through pipeline 1 is also provided with several modified energy-gathering reflective surface structures 5; any modified energy-gathered reflective surface structure 5 is in the shape of an ellipse arc, and the concave surface of the arc shape is in the ultrasonic transducer group The inflection point area of the V-shaped path of ultrasonic transmission and reception; after the signal sent from the ultrasonic transducer at the transmitting end is focused and reflected by the modified energy-gathering reflective surface structure, the strength of the received and transmitted ultrasonic signal is enhanced and the deviation of the ultrasonic signal is corrected. Move and increase the range of the flowmeter to realize the effective reception of the ultrasonic signal by the ultrasonic transducer at the receiving end.

As shown in Figure 1, the projections or signal transmission paths of the first ultrasonic transducer 401 and the second ultrasonic transducer 402, the third ultrasonic transducer 403 and the fourth ultrasonic transducer 404 on the flow channel cross section The angle between the planes is between 30° and 90°. The measurement of multiple sets of ultrasonic transducer groups can obtain relatively more comprehensive and complete sensing data, thereby providing data support for optimizing the flow calculation through the flow channel through the algorithm, and greatly reducing the measurement error caused by a single pair of sensors.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (10)

1. A reflective multi-channel ultrasonic gas flowmeter flow channel comprises a straight-through pipeline, and the straight-through pipeline is provided with an inlet port and an outlet port; on the straight-through pipeline, several ultrasonic transducer groups are arranged, and it is characterized in that: straight-through pipeline A gas rectification structure is provided on the side of the pipeline close to the inlet end; the gas rectification structure includes an airflow channel with a honeycomb structure in cross section, and the airflow channel is parallel to the axial direction of the straight-through pipeline as a whole. 2. A reflective multi-channel ultrasonic gas flowmeter flow channel according to claim 1, characterized in that: the inlet end of the straight-through pipe is provided with a guide ring, and the guide ring is generally tapered or Trumpet-shaped, and the inner wall of the longitudinal section of the guide ring is streamlined. 3. A reflective multi-channel ultrasonic gas flowmeter flow channel as claimed in claim 2, characterized in that: the gas rectification structure satisfies L≥10D _H ; wherein L is the length of the gas rectification structure, and D _H is the air flow Channel is the hydraulic diameter of the honeycomb cells in the honeycomb structure and is the characteristic length of non-circular pipe flow. 4. A reflective multi-channel ultrasonic gas flowmeter flow channel as claimed in claim 3, characterized in that: the hydraulic diameter D _H of the honeycomb cell = 4A/P, wherein A is the process diameter of the honeycomb cell Flow area, P is the wetted perimeter of the honeycomb cell. 5. A reflective multi-channel ultrasonic gas flowmeter flow channel according to any one of claims 1 to 3, characterized in that: the gas rectification structure satisfies: d≥50a, where d is the air flow channel The diameter of the inscribed circle of the honeycomb cell in the honeycomb structure, a is the wall thickness of the side wall of the honeycomb cell. 6. A reflective multi-channel ultrasonic gas flowmeter flow channel as claimed in claim 5, characterized in that: the diameter d of the inscribed circle of the honeycomb cells in the honeycomb structure of the air flow channel satisfies 0.077D≤d≤ 0.173D, where D is the flow channel diameter. 7. The channel of a reflective multi-channel ultrasonic gas flowmeter according to claim 1, characterized in that: the outer edge of the gas rectifying structure and the inner diameter of the straight-through pipeline are connected by an interference fit. 8. A reflective multi-channel ultrasonic gas flowmeter flow channel as claimed in claim 1, characterized in that: the number of the ultrasonic transducer groups is not less than 2, and any ultrasonic transducer group contains two an ultrasonic transducer, the ultrasonic transducer is an ultrasonic transmitter-ultrasonic receiver integrated transducer; two ultrasonic transducers in any ultrasonic transducer group are installed on the straight-through pipeline at a V-shaped angle, The V-shaped included angle is between 40° and 90°. 9. A reflective multi-channel ultrasonic gas flowmeter flow channel as claimed in claim 8, characterized in that: the inner wall of the straight-through pipeline is also provided with several modified energy-gathering reflective surface structures; The reflective surface structure is in the shape of an arc surface, and the concave surface of the arc shape is located in the inflection point area of the V-shaped path of the ultrasonic wave transmission and reception in the ultrasonic transducer group. 10. A reflective multi-channel ultrasonic gas flowmeter flow channel as claimed in claim 1 or 8, wherein the projected angle α of at least two sets of ultrasonic transducer groups on the cross section of the flow channel is at Between 30° and 90°.