A Test Method for the Flow Coefficient of a Marine Gas Turbine Compressor Stage

Abstract

The object of the present invention is to provide a test method for the flow coefficient of a marine gas turbine compressor stage. The present invention only needs to conventionally measure parameters such as the inter-stage total pressure, static pressure, and total temperature in the compressor performance test, and then the flow coefficient values of each stage of the compressor can be quickly obtained. Furthermore, it can intuitively analyze whether the matching of the flow capacity between each stage of the compressor meets the design expectation, providing an effective way for evaluating the matching effect of the flow capacity of each stage, and having good engineering practicability. At the same time, this method is not limited to the compressor of marine gas turbines, and is also applicable to the performance test processes of various axial compressors such as aeroengines and industrial gas turbines.

Description

Technical Field

[0001] The present invention relates to a gas turbine testing method, specifically a compressor testing method. Background Art

[0002] As a core component of a marine gas turbine, the performance of the compressor directly determines the performance level of the whole machine. The most effective way to evaluate the performance indicators of the compressor is to measure its performance parameters through component tests. Through the component performance test of the compressor, it can be verified whether the performance indicators of the compressor meet the design requirements. At the same time, inter-stage performance measurement can also be carried out to study whether the flow state of the gas inside the compressor and the inter-stage matching meet the design expectations, so as to provide a basis for its improvement and optimization design. With the increasing refinement of the compressor aerodynamic design means, the requirements for the test parameters of the compressor performance test are also increasing. The traditional compressor performance test mainly measures the total performance indicators such as flow rate, pressure ratio, and efficiency. The inter-stage measurement mainly focuses on the pressure ratio and efficiency parameters of each stage. Although it can reflect the performance of each stage to a certain extent, it cannot give a good judgment on the matching effects such as the flow capacity and load distribution of each stage of the compressor. Therefore, starting from the key parameters that determine the inter-stage matching effect in the compressor aerodynamic design, an effective test method for the key aerodynamic parameters between the compressor stages needs to be established to provide a more direct and accurate test basis for the aerodynamic design. This is of great significance for improving the performance level of the marine gas turbine compressor and the progress of the design technology. Summary of the Invention

[0003] The purpose of the present invention is to provide a test method for the stage flow coefficient of a marine gas turbine compressor, which can solve the technical problem of testing the matching effect of the flow capacity of each stage in the performance test of the marine gas turbine compressor.

[0004] The purpose of the present invention is achieved as follows:

[0005] A test method for the stage flow coefficient of a marine gas turbine compressor according to the present invention is characterized by including the following steps:

[0006] (1) Measuring the intake air flow rate and physical speed of the compressor: According to the compressor aerodynamic performance test specification, use a flow tube to measure the mass flow rate G at the inlet of the compressor, and use a speed sensor to measure the physical speed n of the compressor;

[0007] (2) Determining the layout scheme of the inter-stage aerodynamic parameter measurement points: Arrange the inter-stage total pressure, static pressure, and total temperature aerodynamic parameter measurement points between the stages of the compressor. While meeting the requirements for the number of measurement points, consider the blockage effect of the probe or sensing part on the internal flow path of the compressor, and ensure that the sum of the areas of the probes or sensing parts in each measurement section and the ratio of the flow area at the corresponding flow path position meet the requirements of the performance test;

[0008] (3) Process the test data of inter-stage aerodynamic parameters: According to the test requirements, select one of the three methods of arithmetic mean, area-weighted mean or mass-weighted mean to calculate the total pressure of each measurement section between stages static pressure p i , total temperature T i * , and according to the position of the measurement section, correct the total pressure of each measurement section between stages static pressure p i ;

[0009] (4) Calculate the flow coefficient of the compressor stage: According to the definition of the flow coefficient, calculate the flow coefficient φ of each stage i based on the final test data measured in the above steps, and finally obtain the test results of the flow coefficient of the compressor stage.

[0010] The present invention may further include:

[0011] 1. In step (2), when the compressor is designed with inter-stage air extraction, measure the extraction flow rate G b .

[0012] 2. In step (3), according to the position of the measurement section, correct the total pressure of each measurement section between stages static pressure p i by multiplying by the corresponding coefficient according to the specific position of each measurement section through the three-dimensional numerical simulation results or the blowing test data of the stator blade cascade to obtain the total pressure static pressure p i,c at the inlet of this stage.

[0013] 3. In step (4), calculate the flow coefficient φ of each stage i using the following formula:

[0014]

[0015] where C a,i is the axial velocity at the inlet of this stage, and U i is the circumferential velocity at the tip of the rotor blade at the inlet of this stage;

[0016] Among them, the axial velocity C at the inlet of this stage a,i is calculated by the following formula:

[0017]

[0018] where G i is the inlet flow rate of this stage. When there is no air extraction in the previous stages of this stage, G i = G; when there is air extraction in the previous stages of this stage, G i = G - G b ;

[0019] A i is the flow area of the inlet of this stage R t,i and R h,i are respectively the outer diameter and inner diameter of the inlet annulus of this stage;

[0020] R is the gas constant;

[0021] ε(λ i ) is the aerodynamic function at the inlet of this stage;

[0022] The circumferential velocity U at the tip of the rotor blade at the inlet of this stage i is calculated by the following formula:

[0023]

[0024] The advantages of the present invention are as follows:

[0025] (1) The present invention can accurately obtain the distribution of the flow coefficient of each stage of the compressor, and then intuitively analyze whether the flow capacity matching between each stage of the compressor meets the design expectations, providing an effective way for evaluating the matching effect of the flow capacity of each stage.

[0026] (2) The present invention only needs to measure the conventional parameters such as the total pressure, static pressure, and total temperature between stages in the compressor performance test to quickly obtain the flow coefficient values of each stage of the compressor, so as to evaluate the flow capacity of each stage of the compressor, and has good engineering practicability.

[0027] (3) The present invention is not limited to the compressors of marine gas turbines, and is also applicable to the performance test processes of various axial compressors such as aeroengines and industrial gas turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be described in more detail with reference to the accompanying drawings as follows:

[0030] Combined with Figure 1 , the specific implementation manner of the present invention is as follows:

[0031] Step 1: Measure the inlet flow rate and physical rotation speed of the compressor. According to the compressor aerodynamic performance test specification, use a flow tube to measure the mass flow rate G at the inlet of the compressor and use a rotational speed sensor to measure the physical rotation speed n of the compressor.

[0032] Step 2: Determine the layout scheme of inter-stage aerodynamic parameter measurement points. Determine the layout scheme of inter-stage aerodynamic parameter measurement points. Select appropriate positions between each stage of the compressor to arrange measurement points for inter-stage total pressure, static pressure, and total temperature aerodynamic parameters. While meeting the requirements for the number of measurement points, the blockage effect of the probe or sensing part on the internal flow path of the compressor should be considered to ensure that the ratio of the sum of the areas of the probes or sensing parts in each measurement section to the flow area at the corresponding flow path position meets the requirements of the performance test.

[0033] When there is inter-stage air extraction designed for the compressor, it is also necessary to measure the air extraction flow rate G b for measurement.

[0034] Step 3: Process the test data of inter-stage aerodynamic parameters. According to the test requirements, select one of the three methods: arithmetic mean, area-weighted mean, or mass-weighted mean, to calculate the total pressure static pressure p i and total temperature T i * at each inter-stage measurement section. And according to the position of the measurement section, correct the total pressure static pressure p i at each inter-stage measurement section. The correction can be carried out by multiplying by the corresponding coefficient according to the specific position of each measurement section through the three-dimensional numerical simulation results or blowing test data of the stator vane cascade to obtain the total pressure static pressure p i,c at the inlet of this stage.

[0035] Step 4: Calculate the flow coefficient of the compressor stage. According to the definition of the flow coefficient, calculate the flow coefficient φ i of each stage based on the final test data measured in the above steps:

[0036]

[0037] where C a,i is the axial velocity at the inlet of this stage, and U i is the circumferential velocity at the tip of the rotor blade at the inlet of this stage.

[0038] The axial velocity C a,i at the inlet of this stage is calculated by the following formula:

[0039]

[0040] where G i is the inlet flow rate of this stage. When there is no air extraction in the previous stages of this stage, G i = G; when there is air extraction in the previous stages of this stage, G i = G - G b ;

[0041] A i is the flow-through annulus area at the inlet of this stage, Rt,i , R h,i are respectively the outer diameter and inner diameter of the inlet annulus of this stage;

[0042] R is the gas constant, and for air, R = 287.06 J / (kg·K) can be taken;

[0043] ε(λ i ) is the aerodynamic function at the inlet of this stage, and can be obtained from the aerodynamic function table.

[0044] The circumferential velocity U at the tip of the rotor blade at the inlet of this stage i is calculated by the following formula:

[0045]

[0046] The test method for the flow coefficient of the compressor stage of the marine gas turbine proposed by the present invention is universal, not only limited to the compressor of the marine gas turbine, but also applicable to the performance test processes of various axial compressors such as aeroengines and industrial gas turbines.

Claims

1. A test method for the flow coefficient of a marine gas turbine compressor stage, characterized in that: The method includes the following steps: (1) Measuring the intake air flow rate and physical rotational speed of the compressor: According to the pneumatic performance test specifications of the compressor, a flow tube is used to measure the mass flow rate G at the inlet of the compressor, and a rotational speed sensor is used to measure the physical rotational speed n of the compressor; (2) Determining the layout scheme of aerodynamic parameter measurement points between stages: Aerodynamic parameter measurement points of total pressure, static pressure, and total temperature are arranged between each stage of the compressor. While meeting the requirements for the number of measurement points, the blockage effect of the sensing part on the internal flow passage of the compressor is considered to ensure that the ratio of the sum of the areas of the sensing parts of each measurement section to the flow area of the corresponding flow passage position meets the requirements of the performance test; (3) Perform the processing of the inter-stage aerodynamic parameter test data: According to the test requirements, select one of the three methods of arithmetic mean, area-weighted mean or mass-weighted mean to calculate the total pressure of each measurement section between stages static pressure p i , total temperature T i * , and according to the position of the measurement section, correct the total pressure of each measurement section between stages static pressure p i ; (4) Calculate the compressor stage flow coefficient: According to the definition of the flow coefficient, calculate the flow coefficient φ of each stage based on the final test data measured in the above steps i , and finally obtain the test results of the compressor stage flow coefficient; Calculate the flow coefficient φ at all levels in step (4) i , using the following formula: where C a,i is the axial velocity at the inlet of this stage, and U i is the circumferential velocity at the tip of the moving blade at the inlet of this stage; Among them, the axial velocity C of this stage at the inlet a,i is calculated by the following formula: where, G i is the inlet flow rate of this stage, is the total pressure at the inlet of this stage. When there is no bleed air in the previous stages of this stage, G i = G; when there is bleed air in the previous stages of this stage, G i = G - G b , G b is the bleed air flow rate; A i is the inlet flow annulus area at this stage, R t,i , R h,i are respectively the outer diameter and inner diameter of the inlet annulus at this stage; R is the gas constant; ε(λ i ) is the pneumatic function of the import at this level; The circumferential velocity U at the tip of the inlet moving blade of this stage i is calculated by the following formula:

2. A test method for the flow coefficient of a marine gas turbine compressor stage according to claim 1, characterized in that: In step (2), when the compressor is designed with inter-stage air extraction, the air extraction flow rate G b is measured.

3. A test method for the flow coefficient of a marine gas turbine compressor stage according to claim 1, characterized in that: In step (3), according to the measurement section positions, the total pressure static pressure p i of each measurement section between stages is corrected. Through the three-dimensional numerical simulation results or blowdown test data of the stator blade cascade, according to the specific positions of each measurement section, it is multiplied by the corresponding coefficient for correction to obtain the total pressure static pressure p i,c .

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