CN107178523B - Back blade automatic adjustment device and turbomachinery using it - Google Patents

Abstract

The present disclosure provides a back vane automatic adjustment device and a turbomachine employing the same. This back of body blade automatic regulating apparatus includes: the force transducer is arranged between the thrust bearing and the shaft and is used for measuring the axial thrust generated by the thrust bearing to the shaft; at least one adjustable back blade fixed to the back of the impeller and with adjustable radial angle. The automatic back vane adjusting device and the turbine machine using the same adopt the adjustable back vane mode, realize the adjustment of the axial balance force of the back vane, and have strong innovation and engineering realization value.

Description

Back blade automatic adjustment device and turbomachinery using it

technical field

The disclosure belongs to the fields of fluid machinery, energy power equipment and power generation systems, and relates to an automatic adjustment device for back blades and a turbomachinery using the same.

Background technique

Turbomachinery is a general term for rotary fluid machines with blades. As a type of turbomachinery, a compressor is a machine that increases the pressure of a compressible fluid by using mechanical energy, and can be divided into axial flow compressors and centrifugal compressors, of which the centrifugal compressor is a blade rotary Compressor, that is, a turbo compressor. When the working fluid passes through the compressor, it is driven by the high-speed rotating blades on the impeller, and flows to the edge of the impeller under the action of centrifugal force. The boosting effect is realized through the diffuser. The centrifugal compressor can be divided into There are single-stage and multi-stage compressors, where a single-stage compressor is fitted with a single rotor, and multi-stage compressors with multiple rotors connected in series.

As an innovative energy power technology, supercritical carbon dioxide (SCO ₂ ) Brayton cycle uses supercritical carbon dioxide as the working medium of the power cycle system. It has been valued and recognized by research institutions at home and abroad. In particular, carbon dioxide has the advantages of moderate critical pressure, good stability and nuclear physical properties, non-toxicity and abundant reserves. The _SCO2 cycle is considered to be one of the most promising power cycles for nuclear reactors (fourth generation nuclear power). It has potential applications in new gas turbines, thermal power and solar power generating sets.

The compressor in the SCO ₂ power cycle is not only the premise to realize the thermal power conversion of the expander, but also the largest energy-consuming part of the system. Its performance directly affects the performance and operation stability of the entire power generation system. Different from turbomachines that use water, air, and gas as working fluids, SCO ₂ compressors face challenges such as more complex working fluid characteristics, high temperature and high pressure working parameters, and high power density. In particular, the absolute pressure difference between the front and back of the impeller of the SCO ₂ compressor is large, and the density of the SCO ₂ working medium is close to that of liquid, resulting in a huge axial thrust on the bearing, which is very easy to damage the bearing and affect the safe service of the system. Although the back-to-back type of turbine and compressor can be adopted to avoid the problem of excessive axial force, it is only applicable to small power units, and the expansion of the SCO ₂ power cycle still cannot bypass the problem of excessive axial force of the compressor.

The structure of the back blade is often used in hydraulic machinery, such as pumps, turbines, etc., and is especially suitable for the seal of conveying harsh liquid media containing solid particles, such as screw centrifugal pumps. The back blades of the impeller are commonly found in centrifugal pump impellers. They are a number of radial blades arranged on the back cover. On the one hand, they can reduce the pressure at the seal and prevent leakage at the shaft seal. On the other hand, they can also balance part of the axial force. The back vane rotates with the impeller and forces the liquid to rotate, making the liquid rotate at a greater angle than without the back vane. It is known from fluid mechanics that at this time, the partial pressure head of the liquid acting on the blade rear cover plate is transformed into a velocity head, so that the liquid pressure value in the rear pump chamber is reduced, so the axial force acting on the impeller is obtained partial balance.

The pressure at the outlet of the SCO ₂ compressor is above 20MPa. Arranging the back vane structure on the back of the impeller can not only balance the axial force, but also reduce the sealing pressure, which has important engineering practical significance. In addition, compared with other power components, the SCO ₂ compressor has a wide range of operating conditions and takes a long period of time to start and stop, so the axial force generated by it will also change accordingly. Once the traditional back blade structure is designed, the axial balance force generated by it cannot be adjusted, and the back blade may have excessive balance due to excessive balance force.

public content

(1) Technical problems to be solved

The present disclosure provides an automatic adjustment device for back blades and a turbomachine using the same, so as to at least partly solve the above-mentioned technical problems.

(2) Technical solutions

According to one aspect of the present disclosure, there is provided an automatic adjustment device for back blades, including: a load cell, arranged between the thrust bearing and the shaft 10, for measuring the axial thrust generated by the thrust bearing toward the shaft; at least one The adjustable back blade is fixed on the back side of the impeller 20, and its angle relative to the radial direction of the shaft is adjustable.

In some embodiments of the present disclosure, the adjustable back blade is mounted on the back of the impeller through a rotatable fastener, and the position where the adjustable back blade is fixed by the rotatable fastener is located in the middle.

In some embodiments of the present disclosure, a control mechanism is also included, configured to adjust the angle of the adjustable back blade relative to the radial direction of the shaft according to the axial thrust measured by the load cell.

In some embodiments of the present disclosure, the control mechanism includes: a back blade rotation angle control mechanism, connected to at least one adjustable back blade; a calculation device, based on the axial thrust measured by the load cell in real time, to calculate the adjustable back blade The rotation angle is required; the programmable logic controller controls the rotation angle control mechanism of the back blade to adjust the rotation angle of at least one adjustable back blade to the required rotation angle according to the required rotation angle of the adjustable back blade.

In some embodiments of the present disclosure, the calculation device calculates the required rotation angle θ of the adjustable back blade according to the following formula:

Among them, F is the axial thrust measured by the load cell in real time;

ρ is fluid density;

ω is the rotational angular velocity of the impeller;

R _e is the distance from the radially outer edge of the adjustable back blade to the center of rotation when the rotation angle θ is 0;

R _h is the distance between the radial inner edge of the adjustable back blade and the rotation center when the rotation angle θ is 0.

In some embodiments of the present disclosure, it includes: the back blades of the T slices, 4≤T≤8, and the back blades of the T slices are all adjustable back blades.

In some embodiments of the present disclosure, the load cell is a push-pull bidirectional load cell 40 capable of measuring the push-pull bidirectional axial force between the thrust bearing 32 and the shaft 10 .

According to another aspect of the present disclosure, there is also provided a turbomachinery, including: a shaft 10; an impeller 20 arranged radially outside the shaft 10; N thrust bearings arranged radially outside the shaft 10 for Support the shaft 10; M load cells 40 are arranged between a thrust bearing and the shaft 10 for measuring the axial thrust generated by the thrust bearing to the shaft; the adjustable back blade of the T piece is fixed on the impeller 20 On the back side, the angle of the adjustable back blade relative to the radial direction of the shaft is adjustable; the control mechanism is used to adjust the angle of the adjustable back blade relative to the radial direction of the shaft according to the axial thrust measured by the push-pull bidirectional load cell; , N≥1, M≥1, T≥1.

In some embodiments of the present disclosure, it includes: the back blade of the T' piece, wherein: the back blades of the T' piece are all adjustable back blades, T'=T; or the back blade of the T' piece includes: T The adjustable back blade of the slice, T'>T.

In some embodiments of the present disclosure, the turbomachinery is a supercritical carbon dioxide compressor, compressor, steam turbine, expander, or turbomachine.

(3) Beneficial effects

It can be seen from the above technical solutions that the automatic adjustment device for back blades of the present disclosure and the turbomachinery using it adopt the form of adjustable back blades, which realizes the adjustable and automatic control of the axial balance force of the back blades, and has a strong Innovation and engineering to realize value.

Description of drawings

FIG. 1 is a structural schematic diagram of a supercritical carbon dioxide compressor using an automatic adjustment device for back blades according to an embodiment of the present disclosure.

Fig. 2 is a schematic diagram of the adjustable back blade inclination angle when the axial balance force is maximum and minimum in the supercritical carbon dioxide compressor shown in Fig. 1 .

[Description of main component symbols of the embodiment of the present disclosure in the accompanying drawings]

10-axis;

20-impeller; 21-static seal;

31, 32-thrust bearing;

40-Push-pull bidirectional load cell;

51～56-adjustable back blade;

61 - computer;

62 - Programmable logic controller (PLC).

Detailed ways

The disclosure provides an automatic adjustment device for back blades and a turbomachinery using the same, which can adjust the balance force generated by the back blades in real time according to the axial force, and has strong innovation and engineering value.

In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

In an exemplary embodiment of the present disclosure, a supercritical carbon dioxide compressor using an automatic adjustment device for back blades is provided. FIG. 1 is a structural schematic diagram of a supercritical carbon dioxide compressor using an automatic adjustment device for back blades according to an embodiment of the present disclosure. Fig. 2 is a schematic diagram of the adjustable back blade inclination angle when the axial balance force is maximum and minimum in the supercritical carbon dioxide compressor shown in Fig. 1 .

As shown in Fig. 1 and Fig. 2, the supercritical carbon dioxide gas compressor of present embodiment application back vane automatic adjustment device comprises: shaft 10; Impeller 20, is arranged on the radial outside of shaft 10; 2 thrust bearings (31,32) , arranged on the radially outer side of the shaft 10, used to support the fixed shaft 10; a push-pull bidirectional load cell 40, arranged between a thrust bearing and the shaft 10, used to measure the axial force produced by the thrust bearing towards the shaft Thrust; 6 adjustable back blades (51-56), fixed on the back of the impeller 20, the adjustable angle of the adjustable back blades relative to the shaft radial direction; For the measured axial thrust, adjust the angle of the adjustable back blade relative to the radial direction of the shaft; wherein, N≥1, M≥1, T≥1.

Each component of the supercritical carbon dioxide compressor using the back blade automatic adjustment device in this embodiment will be described in detail below.

As for the shaft 10 and the impeller 20 in this embodiment, they are not different from the relevant components of a supercritical carbon dioxide compressor in the field, and will not be described in detail here.

Please refer to Figure 1 and Figure 2. In this embodiment, 6 back blades are uniformly arranged on the back of the impeller, and the 6 back blades are all adjustable back blades, that is, they can be adjusted relative to the radial direction of the shaft. angle. The 6 adjustable back blades are mounted on the back of the impeller through rotatable fasteners and rotate with the impeller and shaft. Wherein, the position where the adjustable back blade is fixed by the rotatable fastener is located in the middle.

In other embodiments of the present disclosure, the number of dorsal leaves can be adjusted, and can be 4 to 8, generally 4 or 6 leaves. Moreover, it may also be set that part of the back blades are adjustable back blades, and part of the back blades are fixed type back blades.

It should be noted that by adjusting the angle of the back blade relative to the radial direction of the shaft, the rotation driving effect of the back blade on the working fluid can be changed, thereby changing the flow rate of the working fluid to realize the adjustment of the static pressure of the working fluid. In Fig. 2 (a), the back vane is arranged along the radial direction of the shaft, and at this time it produces the largest axial balance force; The balance force is the smallest.

Please continue to refer to Fig. 1, the static seal 21 is installed on the shaft end of the back of the impeller 20, two thrust bearings (31, 32) are installed on the shaft 10, and the push-pull bidirectional load cell 40 is arranged on a thrust bearing 32 away from the blades .

That is to say, in this embodiment, two thrust bearings (31, 32) and one push-pull bidirectional load cell 40 are provided. However, in other embodiments of the present disclosure, the number of thrust bearings and push-pull bidirectional load cells can also be adjusted as required.

Please continue to refer to FIG. 1 , the control mechanism includes: a computer 61 , a programmable logic controller (PLC) 62 and a back blade rotation angle control mechanism (not shown). Wherein, the computer 61 measures the axial thrust in real time according to the push-pull bidirectional force sensor 40, calculates the appropriate balance force that the adjustable back blade needs to generate at this time, and then calculates the required rotation angle of the adjustable back blade. According to the required rotation angle of the back blade, the programmable logic controller controls the operation of the back blade rotation angle control mechanism to adjust the rotation angle of the back blade to the required rotation angle.

Wherein, the computer 61 calculates the required rotation angle θ of the back blade by the following formula:

Among them, F is the axial thrust measured by the load cell in real time, and its unit is N;

ρ—fluid density, unit is kg/m ³ ;

ω——rotational angular velocity of the impeller, in rad/s;

R _e —— when the rotation angle θ is 0, the distance between the radially outer edge of the back blade and the rotation center, in m;

R _h - when the rotation angle θ is 0, the distance between the radially inner edge of the back blade and the rotation center, in m;

The following introduces the working principle of the back blade automatic adjustment device of the present embodiment and the compressor applying it: when the shaft 10 starts to rotate and the impeller 20 of the SCO ₂ compressor works, the adjustable back blades (51-56) follow the same rotation speed At this time, the difference between the axial force F1 generated by the SCO ₂ compressor impeller 20 and the balance force F2 generated by the adjustable back blade (51-56) will act on the thrust bearings (31, 32); The push-pull bidirectional load cell 40 on the bearing 32 measures the axial thrust in real time, and transmits the pressure signal to the computer for calculation and analysis to obtain the appropriate angle of the adjustable back blade, which is controlled by the programmable logic controller 62 and the rotation angle of the back blade The mechanism adjusts the angle of the adjustable back vane (51-56), so that the absolute value of the difference between the axial thrust generated by the compressor and the axial balance force produced by the back vane is as close to zero as possible, and the thrust on the bearing is less than target for its safe value. In addition, the supercritical carbon dioxide compressor in this embodiment can also reduce the sealing pressure required to be borne in front of the static seal 21 and reduce the sealing length.

In addition, using the intelligent analysis of computer data to collect the variation law of the axial thrust produced by the SCO ₂ compressor during the start-stop process and the real-time tracking law of the adjustment of the back blade, the angle change law of the back blade is designed when the compressor is started and stopped, The advance control of the angle of the back blade is carried out, so as to further protect the stress on the bearing of the SCO ₂ compressor within the safe range during the start-stop process.

In another embodiment of the present disclosure, an automatic adjustment device for back blades is also provided. The back blade automatic adjustment device is actually the back blade automatic adjustment device in the supercritical carbon dioxide compressor of the first embodiment.

Please refer to Fig. 1, the back blade automatic adjustment device includes: a push-pull bidirectional load cell 40, which is arranged between the thrust bearing 32 and the shaft 10, and is used to measure the axial thrust produced by the thrust bearing to the shaft; the adjustable back blade (51～56), fixed on the back of the impeller 20, the angle of the adjustable back blade relative to the shaft radial direction can be adjusted; the control mechanism is used to adjust the adjustable blade according to the axial thrust measured by the push-pull bidirectional load cell. The angle of the back blade relative to the radial direction of the shaft. Regarding the specific content of the shaft 10, the impeller 20, the thrust bearings (31, 32), the push-pull bidirectional load cell 40, the adjustable back blades (51-56), and the control mechanism, reference may be made to the relevant description of the first embodiment, here No restatement.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It should be noted that, in the accompanying drawings or in the text of the specification, implementations that are not shown or described are forms known to those of ordinary skill in the art, and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those of ordinary skill in the art can easily modify or replace them, for example:

(1) Although the embodiment of the present disclosure takes a supercritical carbon dioxide compressor as an example, those skilled in the art can also apply it to other types of compressors, steam turbines, expanders, and turbines;

(2) In some application scenarios, the push-pull bidirectional force sensor can also be replaced by a push force sensor;

(3) In addition to the computer, other types of computing devices can also be used to realize the task of calculating the rotation angle, such as a single-chip microcomputer, FPGA, and the like.

Based on the above description, those skilled in the art should have a clear understanding of the automatic adjustment device for back blades of the present disclosure and the compressor to which it is applied.

To sum up, the present disclosure arranges a push-pull bidirectional load cell at the bearing of the compressor to measure the axial force on the bearing in real time during the change of the working condition of the compressor, and feed back the pressure value to the controller in time, and adjust it through the controller. The rotation angle of the back blade makes the axial balance force generated by it increase or decrease, and finally the absolute value of the difference between the axial thrust generated by the compressor and the axial balance force generated by the back blade is as close to zero as possible, and the bearing A target whose thrust is less than its safe value. In addition, by collecting the change law of the axial thrust produced by the SCO ₂ compressor during the start-stop process and the real-time tracking law of the adjustment of the back blade, the computer is used to carry out intelligent analysis and processing of the data, so as to design the back blade for the next compressor start-stop. According to the angle change law, the back blade angle is controlled in advance, so as to further protect the bearing force of the SCO ₂ compressor in the process of starting and stopping within the safe range, which has strong innovation and engineering realization value.

It should also be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only referring to the directions of the drawings, not Used to limit the protection scope of this disclosure. Throughout the drawings, the same elements are indicated by the same or similar reference numerals. Conventional structures or constructions are omitted when they may obscure the understanding of the present disclosure.

And the shape and size of each component in the figure do not reflect the actual size and proportion, but only illustrate the content of the embodiment of the present disclosure. Furthermore, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Unless known to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties obtained from the teachings of the present disclosure. Specifically, all numbers used in the specification and claims to represent the content of components, reaction conditions, etc. should be understood to be modified by the term "about" in all cases. In general, the expressed meaning is meant to include a variation of ±10% in some embodiments, a variation of ±5% in some embodiments, a variation of ±1% in some embodiments, a variation of ±1% in some embodiments, and a variation of ±1% in some embodiments ±0.5% variation in the example.

Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

It should be appreciated that in the above description of exemplary embodiments of the disclosure, in order to streamline the disclosure and to facilitate understanding of one or more of the various disclosed aspects, various features of the disclosure are sometimes grouped together into a single embodiment, figure, or in its description. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this disclosure.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present disclosure in detail. It should be understood that the above descriptions are only specific embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims (6)

1. An automatic back vane adjustment device comprising:

the force transducer is arranged between the thrust bearing and the shaft (10) and is used for measuring the axial thrust generated by the thrust bearing to the shaft;

at least one adjustable back blade fixed on the back of the impeller (20) and with an adjustable angle relative to the radial direction of the shaft; the adjustable back blade is arranged at the back of the impeller through a rotatable fastener, and the position of the adjustable back blade fixed by the rotatable fastener is positioned in the middle of the adjustable back blade;

the control mechanism is used for adjusting the radial angle of the adjustable back blade relative to the shaft according to the axial thrust measured by the force transducer;

wherein the control mechanism comprises:

the back blade rotation angle control mechanism is connected with the at least one adjustable back blade;

the calculating device is used for calculating the required rotation angle of the adjustable back blade according to the axial thrust measured by the force transducer in real time;

the programmable logic controller is used for controlling the back blade rotation angle control mechanism to act according to the required rotation angle of the adjustable back blade and adjusting the rotation angle of the at least one adjustable back blade to the required rotation angle;

the computing device computes the required rotation angle θ of the adjustable back blade according to:

f is the axial thrust measured by the force transducer in real time;

ρ is the fluid density;

omega is the rotation angular velocity of the impeller;

R _e when the rotation angle theta is 0, the distance between the radial outer edge of the adjustable back blade and the rotation center is the same;

R _h when the rotation angle theta is 0, the distance between the radial inner edge of the adjustable back blade and the rotation center is adjusted.

2. The back vane automatic adjustment device according to claim 1, comprising: t-piece back blade is 4-8, and the T-piece back blade is an adjustable back blade.

3. The automatic back vane adjustment device of claim 1, wherein the load cell is a push-pull bi-directional load cell (40) capable of measuring push-pull bi-directional axial forces between the thrust bearing (32) and the shaft (10).

4. A turbomachine, comprising:

a shaft (10);

an impeller (20) provided radially outside the shaft (10);

n thrust bearings arranged radially outside the shaft (10) for supporting the shaft (10);

m load cells (40) arranged between a thrust bearing and the shaft (10) for measuring the axial thrust generated by the thrust bearing to the shaft;

an adjustable back blade of the T-shaped blade is fixed on the back surface of the impeller (20), and the angle of the adjustable back blade relative to the axial direction is adjustable;

the control mechanism is used for adjusting the angle of the adjustable back blade relative to the radial direction of the shaft according to the axial thrust measured by the push-pull bidirectional force transducer;

wherein N is equal to or greater than 1, M is equal to or greater than 1, and T is equal to or greater than 1;

the control mechanism includes:

the back blade rotation angle control mechanism is connected with the at least one adjustable back blade;

the calculating device is used for calculating the required rotation angle of the adjustable back blade according to the axial thrust measured by the force transducer in real time;

the programmable logic controller is used for controlling the back blade rotation angle control mechanism to act according to the required rotation angle of the adjustable back blade and adjusting the rotation angle of the at least one adjustable back blade to the required rotation angle;

the computing device computes the required rotation angle θ of the adjustable back blade according to:

f is the axial thrust measured by the force transducer in real time;

ρ is the fluid density;

omega is the rotation angular velocity of the impeller;

R _e when the rotation angle theta is 0, the distance between the radial outer edge of the adjustable back blade and the rotation center is the same;

R _h when the rotation angle theta is 0, the distance between the radial inner edge of the adjustable back blade and the rotation center is adjusted.

5. The turbomachine of claim 4, comprising: back blade of T' sheet, wherein:

the back blades of the T' sheet are all adjustable back blades; or (b)

The back vane of the T' sheet comprises: t' is greater than T.

6. The turbomachine of claim 4 or 5, being a supercritical carbon dioxide compressor, turbine, expander or turbine.

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