A rapid evaluation method for the consistency of flow area of ​​a guide

Abstract

The present application belongs to the field of aircraft engines and gas turbines, and particularly relates to a method for rapid evaluation of the consistency of the flow area of ​​a guide. The flow area of ​​the guide is evaluated by a comparison method. A small group of ASME nozzles and a large group of ASME nozzles are prepared respectively, and a test system is established to calculate the relative geometric areas of the two ASME nozzles. The batch-produced guides to be tested are placed in the same environment for testing, and the effective flow area of ​​each batch-produced guide to be tested is obtained by interpolation according to the interpolation calculation formula; the effective flow area value of the batch-produced guide to be tested is compared with the standard guide, and the consistency evaluation of the effective flow area of ​​the batch-produced guide is completed. It has the following advantages: rapid evaluation of the flow area, simple measurement process, and can be measured within 1 hour; no additional treatment of the guide is required, and the operability is good; normal temperature, low speed, and low pressure air is used as the flow medium, and the measurement energy consumption is low; there are few measurement parameters and it is easy to use.

Description

Technical Field

[0001] The present application belongs to the field of aero engines and gas turbines, and in particular relates to a method for quickly evaluating the consistency of a guide flow area. Background Art

[0002] The effective flow area of ​​the guide vanes of modern aircraft engines and gas turbines is an important factor affecting parameters such as engine flow, speed, surge margin, exhaust temperature, etc., and needs to be strictly controlled during the design, manufacturing and assembly of the engine. However, due to the complex three-dimensional spatial structure of the guide vanes, the large-scale measurement of the effective flow area of ​​mass-produced guide vanes and the consistency evaluation face multiple challenges in terms of detection speed, detection efficiency, and detection accuracy.

[0003] The technologies that are closest to the present invention in the existing implementation schemes include:

[0004] 1. Water flow method. This method calculates the area of ​​the guide being tested by measuring the time it takes for water of the same flow rate to pass through the standard guide and the guide being tested. The main steps include: 1. Obtaining the measurement data of the standard guide and determining it as the standard measurement data; 2. Obtaining the liquid level height information and water pressure information in the water storage tank, and adjusting them to meet the preset test conditions; 3. Opening the valve group to allow water of a preset flow rate to pass through the guide being tested, and obtaining the time required for the water to flow through the guide being tested; 4. Determining the exhaust area of ​​the guide being tested based on the time it takes for water to pass through, the preset flow rate of water, and the standard measurement data.

[0005] 2. Geometric measurement method. This method determines the effective flow area of ​​the guide by scanning the throat geometric window in the guide flow channel. The main steps include: 1. Determine the throat section of the guide; 2. Control the scanning equipment to scan the throat section to obtain the scanning section; 3. Construct a quadrilateral based on the four vertices of the scanning section, and obtain the area defined by the scanning trajectory line between each side of the quadrilateral and the corresponding two adjacent vertices; 4. Calculate the area of ​​the throat section based on the area of ​​the quadrilateral and the area defined by the scanning trajectory line between each side of the quadrilateral and the corresponding two adjacent vertices.

[0006] 3. Cavitation test method. This method measures the reference throat area of ​​the standard guide and the guide to be tested in the cavitation state and the effective throat area of ​​the standard guide in the hot test state to measure the effective flow area of ​​the guide to be tested. The main steps include: 1. Using the first fluid as the medium, obtain the first reference throat area of ​​the first guide in the cavitation state; 2. Using the second fluid as the medium, obtain the first effective throat area of ​​the first guide in the hot test state, and obtain the ratio a of the first reference throat area to the first effective throat area by calculation; 3. Using the first fluid as the medium, obtain the second reference throat area of ​​the second guide in the cavitation state; 4. According to the ratio a and the second reference throat area, directly calculate the second effective throat area of ​​the second guide in the hot test state with the second fluid.

[0007] Among them, the water flow method requires the required standard guide data to be obtained in advance. The throttling device with a large flow area has high energy consumption and a long test preparation time. The test piece needs to be dried after the test. The geometric method measures the geometric size of the throat section instead of the actual effective flow area, which has accuracy problems and requires scanning all channels of the guide, which takes a long time for a single machine. The cavitation test method requires the test conditions to reach the critical state of the guide, which has high energy consumption, high test conditions, and a long preparation time.

[0008] Therefore, how to reduce energy consumption and measurement cycle is a problem that needs to be solved. Summary of the invention

[0009] The purpose of this application is to provide a method for quickly evaluating the consistency of the flow area of ​​a guide, so as to solve the problems of high energy consumption and long measurement cycle in the existing standard guide data acquisition.

[0010] The technical solution of the present application is: a method for quickly evaluating the consistency of the flow area of ​​a guide, comprising:

[0011] Estimate the effective flow area A0 of the guide to be tested, prepare a small group ASME nozzle and a large group ASME nozzle, a total of 2 ASME nozzles; the geometric area of ​​the small group ASME nozzle is A1, and the geometric area of ​​the large group ASME nozzle is A2;

[0012] Establish a test system, including: setting a pressure stabilizing cavity in front of the small group ASME nozzle, setting a rectifying grid in front of the pressure stabilizing cavity, setting a fan in front of the rectifying grid, setting several thermometers and differential pressure gauges in the pressure stabilizing cavity; supplying air to the small group ASME nozzle at a low speed through the fan until a set constant pressure difference is generated between the pressure stabilizing cavity and the ambient atmosphere , constant pressure difference Obtained by the differential pressure gauge, and make the maximum Mach number in the ASME nozzle of the group lower than the set value, record the first fan speed n 1 and first flow m1. According to the reading of the thermometer in the pressure-stabilizing cavity, the first air viscosity is obtained by looking up the table , and according to the first air viscosity Calculate the first Reynolds number Re1;

[0013] According to the ASME nozzle discharge coefficient curve C= f (Re), calculate the discharge coefficient C1 of the ASME nozzle of the group, and calculate the relative geometric area C1*A1 of the ASME nozzle of the group;

[0014] Replace the small group ASME nozzle with a large group ASME nozzle, and use the fan to supply air to the large group ASME nozzle at a low speed until a set constant pressure difference is generated between the pressure stabilizing cavity and the ambient atmosphere. And make the maximum Mach number in the large group ASME nozzle lower than the set Mach number, record the second fan speed n 2 and second flow m 2. Look up the table to obtain the second air viscosity: , calculate the second Reynolds number Re2;

[0015] According to the ASME nozzle discharge coefficient curve C= f (Re), obtain the discharge coefficient C2 of the large group ASME nozzle, and calculate the relative geometric area C2*A2 of the large group ASME nozzle;

[0016] Replace the large group of ASME nozzles with standard guides and batch production guides to be tested; use the fan to supply air to the standard guides and batch production guides at a low speed to form the same constant pressure difference , get the fan speed n 0, according to the interpolation calculation formula, the effective flow area of ​​the standard guide and the effective flow area of ​​each batch of guides to be tested are obtained by interpolation ;

[0017] The effective flow area of ​​the guide to be tested in batch production Compare with the effective flow area of ​​the standard guide to complete the consistency evaluation of the effective flow area of ​​batch-produced guides.

[0018] Preferably, the small group of ASME nozzles are ASME nozzles with a geometric area A1 ranging from 0.5A0 < A1 < 1.0A0, and the large group of ASME nozzles are ASME nozzles with a geometric area A2 ranging from 1.0A0 < A2 < 1.5A0.

[0019] Preferably, the constant pressure difference It is 100Pa to 1000Pa; the setting value of the maximum Mach number is 0.2.

[0020] Preferably, the calculation formula of the first Reynolds number Re1 is: ; The second Reynolds number Re2 calculation formula is: .

[0021] Preferably, the rectifying grid is designed, the vortex size is judged by the fluctuation of the differential pressure gauge, and a standard value of the fluctuation amount is set; when the vortex size is larger than the standard value of the fluctuation amount, a step amount is set, the axial length or grid thickness of the rectifying grid is increased according to the step amount, and the rectification grid is tested again until the rectifying grid requirements that meet the standard value of the fluctuation amount are obtained.

[0022] Preferably, the differential pressure gauge is located in a vortex-free zone at a gas supply pressure measuring point upstream of the pressure stabilizing cavity and an ambient pressure measuring point.

[0023] Preferably, the fans are all positive displacement fans, and the positive displacement fans selected are at the first flow rate. m 1 to 2nd flow m The flow rate between 2 increases linearly with the rotation speed.

[0024] Preferably, before supplying air at a low speed to the guides to be tested in batch production, a sealing test is performed on the mating surface between the guides to be tested in batch production and the measuring equipment.

[0025] Preferably, the interpolation calculation formula is:

[0026] ;

[0027] In the formula, n 0 is constant pressure difference The lower guide corresponds to the fan speed.

[0028] The guide flow area consistency rapid assessment method of the present application has the following advantages:

[0029] 1. Rapidly assess the flow area, the measurement process is simple and can be measured within 1 hour;

[0030] 2. No need to do additional processing on the guide, good operability;

[0031] 3. Using normal temperature, low speed and low pressure air as the circulation medium, the measurement energy consumption is low;

[0032] 4. Few measurement parameters and easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0034] Figure 1 This is the overall flow chart of this application;

[0035] Figure 2This is a schematic diagram of the overall structure of the test system for this application;

[0036] Figure 3 ASME nozzle discharge coefficient versus Reynolds number for this application. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] A method for quickly evaluating the consistency of the flow area of ​​a guide. In a horizontal flow pipeline with good sealing properties, two ASME nozzles of appropriate groups are supplied with air at room temperature and low pressure, and the air supply Reynolds number Re is measured. According to the discharge coefficient curve C= f (Re), obtain the effective flow areas C1A1 and C2A2 of the two ASME nozzles under the test pressure difference, supply the same pressure difference gas to the guide, and interpolate to obtain the effective flow area of ​​the batch production guide to be tested .

[0039] The interpolation formula is:

[0040]

[0041] In the above formula, n 1 is a constant pressure difference The ASME nozzles in the lower group correspond to the fan speed, r / min;

[0042] n 2 is a constant pressure difference The lower large group ASME nozzle corresponds to the fan speed, r / min;

[0043] n 0 is constant pressure difference The lower guide corresponds to the fan speed, r / min;

[0044] C1 is a constant pressure difference The ASME nozzle discharge coefficient of the lower group;

[0045] C2 is a constant pressure difference ASME nozzle discharge coefficient for the next large group;

[0046] A1 is the geometric area of ​​the ASME nozzle of the group, m 2 ;

[0047] A2 is the geometric area of ​​the large group ASME nozzle, m 2.

[0048] like Figure 1 , the specific steps are as follows:

[0049] Step S100, estimating the effective flow area A0 of the guide to be tested, and preparing a small group of ASME nozzles and a large group of ASME nozzles, a total of 2 ASME nozzles.

[0050] Among them, the small group ASME nozzle is an ASME nozzle with a geometric area A1 of 0.5A0<A1<1.0A0, and the large group ASME nozzle is an ASME nozzle with a geometric area A2 of 1.0A0<A2<1.5A0.

[0051] Step S200, establish a test system, such as Figure 2 , including: setting a pressure stabilizing cavity in front of the small group of ASME nozzles, setting a rectifying grid in front of the pressure stabilizing cavity, setting a fan in front of the rectifying grid, and setting several thermometers and differential pressure gauges in the pressure stabilizing cavity. The fan supplies air to the small group of ASME nozzles at a low speed until a set constant pressure difference is generated between the pressure stabilizing cavity and the ambient atmosphere. , constant pressure difference Obtained by the differential pressure gauge, and make the maximum Mach number in the ASME nozzle of the group lower than the set value, record the first fan speed n 1 and first flow m 1. In this process, the airflow blown out by the fan is rectified through the rectifier grid to ensure the stability of the airflow. According to the reading of the thermometer in the pressure-stabilizing cavity, the first air viscosity is obtained by looking up the table , and according to the first air viscosity Calculate the first Reynolds number Re1.

[0052] Preferably, a constant pressure difference It is 100Pa to 1000Pa; the setting value of the maximum Mach number is 0.2.

[0053] Preferably, the first Reynolds number Re1 is calculated as: .

[0054] Preferably, the rectifier grid should have an appropriate axial length so that the air supply upstream of the pressure-stabilizing cavity is stable, uniform, and free of large-scale vortices; the size of the vortex is judged by the fluctuation of the differential pressure gauge, and a standard value of the fluctuation amount is set; when the vortex size is larger than the standard value of the fluctuation amount, a step amount is set, and the axial length or grid thickness of the rectifier grid is increased according to the step amount, and the test is carried out again until the rectifier grid requirements that meet the standard value of the fluctuation amount are obtained.

[0055] Preferably, the differential pressure gauge is located in a vortex-free zone at the air supply pressure measuring point upstream of the pressure stabilizing cavity and the ambient pressure measuring point, and can characterize the average intake pressure in the upstream area near the guide or nozzle, so that the pressure difference value of the differential pressure gauge can truly reflect the difference between the average static pressure of the pressure stabilizing cavity and the ambient pressure.

[0056] Step S300, as Figure 3 According to the ASME nozzle discharge coefficient curve C= f (Re), calculate the discharge coefficient C1 of the ASME nozzle of the group, and calculate the relative geometric area C1*A1 of the ASME nozzle of the group;

[0057] Step S400: Replace the small group ASME nozzle with the large group ASME nozzle, and supply air to the large group ASME nozzle at a low speed through the fan until a set constant pressure difference is generated between the pressure stabilizing cavity and the ambient atmosphere. And make the maximum Mach number in the large group ASME nozzle lower than the set Mach number, record the second fan speed n 2 and second flow m 2. Look up the table to obtain the second air viscosity: , calculate the second Reynolds number Re2.

[0058] Preferably, the second Reynolds number Re2 is calculated as: , the maximum Mach number is set to 0.2.

[0059] Step S500, according to the ASME nozzle outflow coefficient curve C= f (Re), obtain the discharge coefficient C2 of the large group ASME nozzle, and calculate the relative geometric area C2*A2 of the large group ASME nozzle.

[0060] Step S600, replace the large group ASME nozzles with standard guides and batch production guides to be tested respectively; supply air to the standard guides and batch production guides to be tested at a low speed through a fan to form the same constant pressure difference , get the fan speed n 0, according to the interpolation calculation formula, the effective flow area of ​​the standard guide and the effective flow area of ​​each batch of guides to be tested are obtained by interpolation .

[0061] Preferably, the fans are all positive displacement fans, and the positive displacement fans selected are at the first flow rate. m 1 to 2nd flow m 2 should have good linearity, that is, the flow rate increases linearly with the speed.

[0062] Preferably, before supplying air at low speed to the mass-produced guides to be tested, a sealing test is performed on the mating surface between the mass-produced guides to be tested and the measuring equipment to ensure that all air supply enters only from the air inlet and is discharged into the atmosphere only from the turbine guide / long-neck nozzle to ensure the accuracy of the test.

[0063] Step S700: the effective flow area of ​​the guide to be tested in batches Compare with the effective flow area of ​​the standard guide to complete the consistency evaluation of the effective flow area of ​​batch-produced guides.

[0064] In summary, the present application adopts the comparative method to evaluate the flow area of ​​the guide. A small group of ASME nozzles and a large group of ASME nozzles are prepared respectively and a test system is established to calculate the relative geometric areas of the two ASME nozzles. The batch-produced guides to be tested are placed in the same environment for testing to evaluate the consistency of the effective flow area of ​​the batch-produced guides.

[0065] The overall advantages are as follows:

[0066] 1. Rapidly assess the flow area, the measurement process is simple and can be measured within 1 hour;

[0067] 2. No need to do additional processing on the guide, good operability;

[0068] 3. Using normal temperature, low speed and low pressure air as the circulation medium, the measurement energy consumption is low;

[0069] 4. Few measurement parameters and easy to use.

[0070] Finally, it should be noted that: the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0071] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for quickly evaluating the consistency of the flow area of ​​a guide, characterized in that: include: Estimate the effective flow area A0 of the guide to be tested, prepare a small group of ASME nozzles and a large group of ASME nozzles, a total of 2 ASME nozzles; The geometric area of ​​the ASME nozzle for the small group is A1, and the geometric area of ​​the ASME nozzle for the large group is A2; A test system is established, including: a pressure stabilizing cavity is set in front of a small group of ASME nozzles, a rectifying grid is set in front of the pressure stabilizing cavity, a fan is set in front of the rectifying grid, and a plurality of thermometers and differential pressure gauges are set in the pressure stabilizing cavity; air is supplied to the small group of ASME nozzles at a low speed through the fan until a set constant pressure difference Δp is generated between the pressure stabilizing cavity and the ambient atmosphere, the constant pressure difference Δp is obtained by the differential pressure gauge, and the maximum Mach number in the small group of ASME nozzles is made lower than the set value, and the first fan speed n1 and the first flow rate m1 are recorded; according to the reading of the thermometer in the pressure stabilizing cavity, a first air viscosity μ1 is obtained by looking up a table, and a first Reynolds number Re1 is calculated according to the first air viscosity μ1; According to the ASME nozzle discharge coefficient curve C=f(Re), calculate the ASME nozzle discharge coefficient C1 of the small group, and calculate the relative geometric area C1*A1 of the ASME nozzle of the small group; Replace the small group ASME nozzle with the large group ASME nozzle, and supply air to the large group ASME nozzle at a low speed through the fan until a set constant pressure difference Δp is generated between the pressure stabilizing cavity and the ambient atmosphere, and the maximum Mach number in the large group ASME nozzle is lower than the set Mach number, record the second fan speed n2 and the second flow m2, obtain the second air viscosity μ2 by looking up the table, and calculate the second Reynolds number Re2; According to the ASME nozzle discharge coefficient curve C=f(Re), the large group ASME nozzle discharge coefficient C2 is obtained, and the large group ASME nozzle relative geometric area C2*A2 is calculated; The large group of ASME nozzles are replaced with standard guides and batch production guides to be tested respectively; the standard guides and batch production guides to be tested are supplied with low-speed air by a fan to form the same constant pressure difference Δp, and the fan speed n0 is obtained. The effective flow area of ​​the standard guide and the effective flow area A of each batch production guide to be tested are obtained by interpolation according to the interpolation calculation formula eff ; The effective flow area A of the guide to be tested in batch production eff Compare with the effective flow area of ​​the standard guide to complete the consistency evaluation of the effective flow area of ​​the batch production guide; The interpolation calculation formula is: Where n0 is the fan speed corresponding to the guide valve under constant pressure difference Δp.

2. The method for quickly evaluating the consistency of the flow area of ​​a guide as claimed in claim 1, characterized in that: The small group of ASME nozzles are ASME nozzles with a geometric area A1 of 0.5A0<A1<1.0A0, and the large group of ASME nozzles are ASME nozzles with a geometric area A2 of 1.0A0<A2<1.5A0.

3. The method for quickly evaluating the consistency of the flow area of ​​a guide as claimed in claim 1, characterized in that: The constant pressure difference Δp is 100Pa to 1000Pa; the setting value of the maximum Mach number is 0.

2.

4. The method for quickly evaluating the consistency of the flow area of ​​a guide as claimed in claim 1, characterized in that: The calculation formula of the first Reynolds number Re1 is: The second Reynolds number Re2 is calculated as follows:

5. The method for rapid evaluation of flow area consistency of a guide as claimed in claim 1, characterized in that: The rectifying grid is designed, the vortex size is judged by the fluctuation of the differential pressure gauge, and the standard value of the fluctuation amount is set; when the vortex size is larger than the standard value of the fluctuation amount, the step amount is set, the axial length or grid thickness of the rectifying grid is increased according to the step amount, and the rectification grid is tested again until the rectifying grid requirements that meet the standard value of the fluctuation amount are obtained.

6. The method for quickly evaluating the consistency of the flow area of ​​a guide as claimed in claim 1, characterized in that: The differential pressure gauge is located in a vortex-free zone at a gas supply pressure measuring point upstream of the pressure stabilizing cavity and an ambient pressure measuring point.

7. The method for quickly evaluating the consistency of the flow area of ​​a guide as claimed in claim 1, characterized in that: The fans are all positive displacement fans, and the flow rate of the selected positive displacement fans between the first flow rate m1 and the second flow rate m2 increases linearly with the rotation speed.

8. The method for quickly evaluating the consistency of the flow area of ​​a guide as claimed in claim 1, characterized in that: Before supplying air at a low speed to the guides to be tested in batch production, a sealing test is performed on the mating surfaces between the guides to be tested in batch production and the measuring equipment.

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