An experimental test method for dimensionless characteristic curves of each stage of a marine gas turbine compressor

Abstract

The object of the present invention is to provide a test method for dimensionless characteristic curves of each stage of a marine gas turbine compressor. The present invention only needs to select appropriate positions between each stage of the compressor for conventional measurements of parameters such as total pressure, static pressure, and total temperature, and then when testing the total general characteristic curve of the compressor, the relationship curves between dimensionless parameters such as stage flow coefficient, stage loading coefficient, and stage efficiency can be quickly and accurately obtained, so as to comprehensively evaluate the flow capacity, compression capacity, flow loss, etc. of each stage within the full operating range, providing an effective way for the analysis and verification of the performance of each stage of the compressor and the matching effect between stages. The test method is simple and practical, and is very suitable for engineering applications. At the same time, this method 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.

Description

Technical Field

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

[0002] The compressor is one of the three core components of a marine gas turbine, and its performance level plays a decisive role in the technical indicators of the whole machine. Therefore, during the development of a marine gas turbine, it is necessary to conduct performance tests on the compressor component to verify whether the performance indicators of the compressor meet the design requirements. On the other hand, in the compressor performance test, the internal flow field of the compressor can be evaluated by detailed measurement of parameters such as inter-stage pressure and temperature to see if it meets the design expectations. It can be said that the compressor component test is both the basis for judging whether its performance meets the standards and can provide effective reference for aerodynamic design.

[0003] Traditional compressor component performance tests mainly measure the total performance indicators such as flow rate, pressure ratio, and efficiency at each test state point. The inter-stage measurement also mainly focuses on the pressure ratio and efficiency parameters of each stage. Although it can provide some reference for the realization of the aerodynamic design effect, it does not comprehensively analyze and judge the performance of each stage of the compressor, nor can it fully evaluate the matching effect between each stage. Currently, compressor design technology is developing rapidly, with various advanced design methods emerging in an endless stream. As a result, the requirements for compressor test and measurement are getting higher and higher, and the compressor component performance test is becoming increasingly refined. In the above context, it is necessary to continuously develop effective test means for the internal flow field and performance parameters of the compressor. Only by comprehensively mastering the performance and matching effect of each stage of the compressor through component tests can an accurate reference basis be provided for compressor design, thereby promoting the progress and improvement of advanced design technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a test method for the dimensionless characteristic curves of each stage of a marine gas turbine compressor, which can solve the problem of comprehensively evaluating the performance and matching effect of each stage in the performance test of the marine gas turbine compressor.

[0005] The purpose of the present invention is achieved as follows:

[0006] A test method for the dimensionless characteristic curves of each stage of a marine gas turbine compressor according to the present invention is characterized by including the following steps:

[0007] (1) Measuring the characteristic curves at different reduced speeds of the compressor: According to the aerodynamic performance test specification of the compressor, conduct isorotational characteristic curve tests within the reduced speed range of the compressor. Each isorotational characteristic curve has no less than seven test state points, covering the entire flow range from the choking boundary to the surge boundary, and determining the total performance parameters of the compressor at each test state point, including the inlet mass flow rate G, pressure ratio π, adiabatic efficiency η ad , physical speed n;

[0008] (2) Measure the inter-stage aerodynamic parameters at each test state point: Arrange the total pressure between each stage of the compressor static pressure p i and total temperature T i * parameter measurement points, and correct the measured values of total pressure and static pressure according to the arrangement positions of the measurement points;

[0009] (3) Calculate the dimensionless characteristic parameters at each test state point: Calculate the flow coefficient φ of each stage of the compressor i and stage loading coefficient ψ i and stage adiabatic efficiency η ad,i ;

[0010] (4) Plot the dimensionless characteristic curves of each stage: including the stage flow coefficient-stage loading coefficient curve and the stage flow coefficient-stage adiabatic efficiency curve of each stage, and finally obtain the test results of the dimensionless characteristic curves of each stage of the compressor.

[0011] The present invention may further include:

[0012] 1. In step (2), when the compressor is designed with inter-stage air extraction, measure the extraction flow rate G b .

[0013] 2. For the inter-stage total pressure, static pressure, and total temperature aerodynamic parameter measurement points in step (2), measure the total pressure and total temperature by arranging probes in the vane cascade channels of the previous stage or by laying sensing parts at the leading edges of the static vanes, and measure the static pressure by setting static pressure holes on the wall or arranging static pressure probes in the vane cascade channels of the static vanes. The ratio of the sum of the areas of the probes or sensing parts in each measurement section to the area of the corresponding flow path position does not exceed 1.5%, and the number of arrangement positions of each parameter measurement point in the circumferential direction of this section is not less than 2.

[0014] 3. The calculation method of the flow coefficient φ of each stage in step (3) is as follows: i The calculation method is as follows:

[0015]

[0016] In the formula, 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 ; R t,i , R h,i are the outer diameter and inner diameter of the inlet annulus of this stage respectively; R is the gas constant; ε(λ i ) is the aerodynamic function at the inlet of this stage;

[0017] The calculation method of the stage loading coefficient ψ of each stage is as follows: i The calculation method is as follows:

[0018]

[0019] Wherein, k i , k i+1 are the adiabatic indexes of the i-th stage and the (i + 1)-th stage, which are obtained by querying the gas physical property table according to the total pressure and total temperature parameters measured at the corresponding measurement cross-section;

[0020] The adiabatic efficiency η of each stage ad,i is calculated as follows:

[0021]

[0022] Wherein, k ave,i is the average adiabatic index at the inlet and outlet of the i-th stage,

[0023] 4. For the stage flow coefficient-stage loading coefficient curve in step (4), with the stage flow coefficient φ i as the abscissa and the stage loading coefficient ψ i as the ordinate, the coordinate values (φ i , ψ i ) of all test state points of this stage are fitted by a polynomial to draw the stage flow coefficient-stage loading coefficient curve, which characterizes the variation law between the flow capacity and the compression capacity of this stage; for the stage flow coefficient-stage adiabatic efficiency curve, with the stage flow coefficient φ i as the abscissa and the stage adiabatic efficiency η ad,i as the ordinate, the coordinate values (φ i , η ad,i ) of all test state points of this stage are fitted by a polynomial to draw the stage flow coefficient-stage adiabatic efficiency curve, which characterizes the variation law between the flow capacity and the flow loss of this stage.

[0024] 5. The fitting polynomial selects a polynomial of degree 2 to 4.

[0025] The advantages of the present invention are as follows:

[0026] (1) The present invention can accurately obtain the relationship curves between dimensionless parameters such as stage flow coefficient, stage loading coefficient, and stage efficiency, so as to comprehensively evaluate the flow capacity, compression capacity, flow loss, etc. of each stage within the full operating condition range, providing an effective way for the analysis and verification of the performance of each stage of the compressor and the matching effect between stages.

[0027] (2) The present invention only needs to select appropriate positions between each stage of the compressor for conventional measurements of parameters such as total pressure, static pressure, and total temperature, and can quickly obtain the dimensionless parameters characterizing the performance of each stage while testing the general characteristic curve of the compressor. The testing method is simple and practical, and is very suitable for engineering applications.

[0028] (3) The present invention is not limited to the compressors of marine gas turbines, and is equally applicable to the performance test processes of various axial compressors such as aero-engines and industrial gas turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be described in more detail with reference to the accompanying drawings as follows:

[0031] Combined with Figure 1 , the specific embodiments of the present invention are as follows:

[0032] Step 1: Measure the characteristic curves at different reduced speeds of the compressor. According to the pneumatic performance test specifications of the compressor, conduct the isospeed characteristic curve test within the common reduced speed range of the compressor. Each isospeed characteristic curve has no less than seven test state points, covering the entire flow range from the choking boundary to the surge boundary, and determine the total performance parameters of the compressor at each test state point, including the inlet mass flow rate G, pressure ratio π, adiabatic efficiency η ad , physical speed n, etc.

[0033] Step 2: Test the inter-stage pneumatic parameters at each test state point. Select appropriate positions between each stage of the compressor to arrange the inter-stage total pressure static pressure p i total temperature T i * parameter measurement points. Usually, multi-point probes are arranged in the cascade channels of the stator blades of the previous stage or the sensing parts are laid at the leading edges of the stator blades to measure the total pressure and total temperature, and the static pressure is measured by setting static pressure holes on the wall surface or arranging static pressure probes in the cascade channels of the stator blades. The sum of the areas of the probes or sensing parts in each measurement section and the area ratio of the corresponding flow path position should not exceed 1.5%, and there are no less than 2 layout positions for each parameter measurement point in the circumferential direction of this section, and the measured values of the total pressure and static pressure are corrected according to the layout positions of the measurement points; when the compressor is designed with inter-stage air extraction, it is also necessary to measure the extraction flow rate G b .

[0034] Step 3: Calculate the dimensionless characteristic parameters at each test state point at each stage. Calculate the flow coefficient φ i , stage loading coefficient ψ i , stage adiabatic efficiency η ad,i of each stage of the compressor by the following method:

[0035] The calculation method of the flow coefficient φ i of each stage is as follows:

[0036]

[0037] In the formula, 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 ; R t,i , R h,i are respectively the outer diameter and inner diameter of the inlet annulus of this stage; R is the gas constant. For air, R = 287.06 J / (kg·K); ε(λ i ) is the aerodynamic function at the inlet of this stage and can be obtained by looking up in the aerodynamic function table according to .

[0038] The load coefficient ψ of each stage i is calculated as follows:

[0039]

[0040] In the formula, k i , k i+1 are the adiabatic exponents of the i-th stage and the (i + 1)-th stage respectively, and can be obtained by querying the gas property table according to the total pressure and total temperature parameters measured at the corresponding measurement cross-section.

[0041] The adiabatic efficiency η of each stage ad,i is calculated as follows:

[0042]

[0043] In the formula, k ave,i is the average adiabatic exponent at the inlet and outlet of the i-th stage,

[0044] Step 4: Plot the dimensionless characteristic curves of each stage. Include the stage flow coefficient-stage load coefficient curve and the stage flow coefficient-stage adiabatic efficiency curve of each stage.

[0045] For the stage flow coefficient-stage load coefficient curve, with the stage flow coefficient φ i as the abscissa and the stage load coefficient ψ i as the ordinate, the coordinate values (φ i , ψ i ) of all test state points of this stage are fitted by polynomials, and then the stage flow coefficient-stage load coefficient curve can be plotted, which characterizes the variation law between the flow capacity and compression capacity of this stage;

[0046] For the stage flow coefficient-stage adiabatic efficiency curve, with the stage flow coefficient φ i as the abscissa and the stage adiabatic efficiency η ad,i as the ordinate, the coordinate values (φ i , η ad,i)By using polynomial fitting, the stage flow coefficient-stage adiabatic efficiency curve can be plotted to characterize the variation law between the flow capacity and flow loss of this stage. The above fitting polynomial can be a 2-4th degree polynomial according to specific requirements.

[0047] Finally, the test results of the dimensionless characteristic curves of each stage of the compressor are obtained.

[0048] The test method for the stage flow coefficient of the marine gas turbine compressor proposed by the present invention is universal, not only limited to the marine gas turbine compressor, 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 dimensionless characteristic curves of each stage of a marine gas turbine compressor, characterized in that: It includes the following steps: (1)Measure the characteristic curves of the compressor at different reduced speeds: According to the compressor aerodynamic performance test specifications, conduct the constant-speed characteristic curve test within the reduced speed range of the compressor. Each constant-speed characteristic curve has no less than seven test state points, covering the entire flow range from the choking boundary to the surge boundary, and determine the total performance parameters of the compressor at each test state point, including the inlet mass flow rate G, pressure ratio π, and adiabatic efficiency η ad , physical speed n; (2) Test the inter-stage pneumatic parameters at each test state point: Arrange the inter-stage total pressure between each stage of the compressor static pressure p i , total temperature T i * parameter measurement points, and correct the measured values of the total pressure and static pressure according to the arrangement positions of the measurement points; (3) Calculate the dimensionless characteristic parameters at the lower level of each test state point: Calculate the flow coefficient φ of each stage of the compressor i , the stage loading coefficient ψ i , the stage adiabatic efficiency η ad,i ; (4) Plot dimensionless characteristic curves at all levels: including the stage flow coefficient-stage loading coefficient curves and stage flow coefficient-stage adiabatic efficiency curves at all levels, and finally obtain the test results of dimensionless characteristic curves at all levels of the compressor.

2. The test method for the dimensionless characteristic curves of each stage of a marine gas turbine compressor according to claim 1 is 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 dimensionless characteristic curves of each stage of a marine gas turbine compressor according to claim 1, characterized in that: For the measurement points of total pressure, static pressure, and total temperature aerodynamic parameters between stages in step (2), the total pressure and total temperature are measured by arranging probes in the cascade channels of the stator blades of the previous stage or by laying sensing parts at the leading edges of the stator blades, and the static pressure is measured by setting static pressure holes on the wall surface or arranging static pressure probes in the cascade channels of the stator blades. The sum of the areas of the probes or sensing parts at each measurement section and the area ratio of the corresponding flow path position do not exceed 1.5%, and the number of arrangement positions of each parameter measurement point in the circumferential direction of this section is not less than 2.

4. A test method for dimensionless characteristic curves of each stage of a marine gas turbine compressor according to claim 1, characterized in that: The flow coefficient φ at all levels in step (3) i The calculation method is as follows: where G i is the inlet flow rate of this stage. When there is no air extraction in the previous stages, G i = G. When there is air extraction in the previous stages, G i = G - G b ; R t,i , R h,i are the outer diameter and inner diameter of the inlet annulus of this stage respectively; R is the gas constant; ε(λ i ) is the aerodynamic function at the inlet of this stage, and G b is the air extraction flow rate; Load factor ψ at all levels i The calculation method is as follows: where k i and k i+1 are the adiabatic indices of the i-th and (i + 1)-th stages, which are obtained by querying the gas physical property table according to the total pressure and total temperature parameters measured at the corresponding measurement cross-section; Adiabatic efficiency η at all levels ad,i The calculation method is as follows: where k ave,i is the average adiabatic index of the i-th stage inlet and outlet, 5. A test method for dimensionless characteristic curves of each stage of a marine gas turbine compressor according to claim 1, characterized in that: In step (4), for the intermediate flow coefficient - stage loading coefficient curve, with the stage flow coefficient φ i as the abscissa and the stage loading coefficient ψ i as the ordinate, the coordinate values (φ i , ψ i ) of all test state points of this stage are fitted using polynomials to plot the stage flow coefficient - stage loading coefficient curve, which characterizes the variation law between the flow capacity and compression capacity of this stage; for the stage flow coefficient - stage adiabatic efficiency curve, with the stage flow coefficient φ i as the abscissa and the stage adiabatic efficiency η ad,i as the ordinate, the coordinate values (φ i , η ad,i ) of all test state points of this stage are fitted using polynomials to plot the stage flow coefficient - stage adiabatic efficiency curve, which characterizes the variation law between the flow capacity and flow loss of this stage.

6. A test method for dimensionless characteristic curves of each stage of a marine gas turbine compressor according to claim 5, characterized in that: The fitting polynomial selects a polynomial of degree 2 to 4.

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