Air-cooled turbine test efficiency evaluation method considering cold air leakage

Abstract

The invention provides an air-cooled turbine test efficiency evaluation method considering cold air leakage, and the method comprises the steps: detecting the total temperature of a turbine inlet, the total pressure of the turbine inlet, the total temperature of a turbine outlet, and the total pressure of the turbine outlet, and carrying out the aerodynamic performance test of a turbine part, the main gas flow of a turbine inlet, the turbine main gas drop pressure ratio, the turbine main gas temperature ratio and the main gas working medium specific heat ratio are obtained; the cold air inlet total temperature and the cold air inlet total pressure of the cold air upstream sealing labyrinth are detected, the flow loss coefficient of labyrinth sealing is obtained, and the flow of cold air flowing through the labyrinth is determined based on the flow loss coefficient, the cold air inlet total temperature and the cold air inlet total pressure; and the isentropic efficiency of the air-cooled turbine test considering the cold air leakage is calculated based on the cold air flow flowing through the labyrinth, the main air flow, the turbine inlet total temperature, the cold air inlet total temperature, the turbine main air temperature ratio, the turbine outlet total temperature, the turbine main air pressure drop ratio, the cold air inlet total pressure, the turbine outlet total pressure and the gas working medium specific heat ratio. According to the invention, the calculation accuracy of the turbine test efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of aero-engine testing technology, and in particular to a method for evaluating the testing efficiency of an air-cooled turbine that takes into account cold gas leakage. Background Technology

[0002] The turbine is a key hot-end component of an aero-gas turbine engine. Turbine test efficiency directly reflects the turbine's design level, and accurate measurement of turbine efficiency plays a crucial role in understanding turbine performance and guiding further improvements and optimizations. Current industry standards stipulate that turbine test efficiency is mainly determined by measuring turbine runout parameters. This involves measuring the turbine inlet and outlet pressure ratio and temperature ratio, and calculating the turbine's isentropic efficiency based on the ratio of rim work to isentropic expansion work. However, considering only runout parameters cannot reflect the true turbine efficiency, hindering comprehensive comparison of turbine design schemes and reducing the accuracy of turbine performance evaluation. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a method for evaluating the test efficiency of an air-cooled turbine that takes into account cold air leakage. This method can reflect the true turbine efficiency, improve the accuracy of turbine test efficiency calculation, solve the problem of inaccurate turbine performance evaluation results caused by not considering cold air leakage in turbine test efficiency measurement, and enable direct comparison and selection of the best option among different schemes during turbine design.

[0004] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows: In a first aspect, embodiments of the present invention provide a method for evaluating the test efficiency of an air-cooled turbine considering cold air leakage, comprising: The turbine inlet total temperature, turbine inlet total pressure, turbine outlet total temperature and turbine outlet total pressure are measured, and the aerodynamic performance of the turbine components is tested to obtain the main gas flow rate at the turbine inlet, the turbine main gas pressure ratio, the turbine main gas temperature ratio and the main gas working fluid specific heat ratio. The total temperature and total pressure of the cold air inlet at the upstream sealing grate are detected to obtain the flow loss coefficient of the grate sealing. Based on the flow loss coefficient, the total temperature and total pressure of the cold air inlet, the flow rate of the cold air flowing through the grate is determined. The isentropic efficiency of the air-cooled turbine test considering cold gas leakage is calculated based on the cold gas flow rate through the grates, the main gas flow rate, the total temperature at the turbine inlet, the total temperature at the cold gas inlet, the turbine main gas temperature ratio, the total temperature at the turbine outlet, the turbine main gas pressure ratio, the total pressure at the cold gas inlet, the total pressure at the turbine outlet, and the specific heat ratio of the working fluid.

[0005] Furthermore, the present invention provides a first possible implementation of the first aspect, wherein the step of calculating the isentropic efficiency of the air-cooled turbine test considering cold gas leakage based on the cold gas flow rate through the comb teeth, the main gas flow rate, the turbine inlet total temperature, the cold gas inlet total temperature, the turbine main gas temperature ratio, the turbine outlet total temperature, the turbine main gas pressure drop ratio, the cold gas inlet total pressure, the turbine outlet total pressure, and the gas working fluid specific heat ratio includes: The ratio of the total inlet temperature of the cold air to the total outlet temperature of the turbine is calculated to obtain the temperature ratio of the cold air. Calculate the ratio of the total pressure at the cold air inlet to the total pressure at the turbine outlet to obtain the cold air pressure drop ratio; The isentropic efficiency of the air-cooled turbine test considering cold gas leakage is calculated based on the temperature ratio of the cold gas, the pressure ratio of the cold gas, the flow rate of the cold gas flowing through the grates, the main gas flow rate, the total temperature of the turbine inlet, the total temperature of the cold gas inlet, the temperature ratio of the turbine main gas, the pressure ratio of the turbine main gas, and the specific heat ratio of the working fluid.

[0006] Furthermore, this embodiment of the invention provides a second possible implementation of the first aspect, wherein the formula for calculating the isentropic efficiency of the air-cooled turbine test is:

[0007] in, The total temperature at the turbine inlet. The total temperature of the cold air inlet. The turbine main air temperature ratio is... The temperature ratio of the air conditioner. The main gas flow rate is... The flow rate of the cold air passing through the comb teeth. The turbine main air pressure ratio is... This refers to the pressure drop ratio of the cold air. The specific heat ratio of the main gas working fluid. The upstream cold air is designated as a number; the temperature ratio of the cold air is related to the total temperature at the cold air inlet and the total temperature at the turbine outlet, and the pressure drop ratio of the cold air is related to the total pressure at the cold air inlet and the total pressure at the turbine outlet.

[0008] Furthermore, this embodiment of the invention provides a third possible implementation of the first aspect, wherein the step of determining the main airflow volume includes: The turbine inlet static pressure and turbine inlet static temperature are detected. The Mach number is determined based on the turbine inlet static pressure, the turbine inlet total pressure, and a gas dynamics function. The average velocity of the turbine inlet airflow is calculated based on the Mach number and the turbine inlet static temperature. The turbine inlet flow rate is calculated based on the average velocity and turbine inlet cross-sectional area to obtain the main gas flow rate.

[0009] Furthermore, this embodiment of the invention provides a fourth possible implementation of the first aspect, wherein the step of determining the flow rate of the cold air passing through the comb teeth based on the flow loss coefficient, the total temperature of the cold air inlet, and the total pressure of the cold air inlet includes: The ideal gas flow rate is determined based on the flow function of the pylon seal, the total temperature of the cold air inlet, and the total pressure of the cold air inlet. The flow rate of cold air passing through the grate teeth is determined based on the type of the grate teeth, the ideal gas flow rate, and the flow loss coefficient; wherein, the type of the grate teeth includes straight-through grate teeth, helical straight-through grate teeth, and stepped grate teeth.

[0010] Furthermore, this embodiment of the invention provides a fifth possible implementation of the first aspect, wherein the type of the grating teeth is the straight-through grating teeth, and the calculation formula for the flow rate of the cold air passing through the grating teeth is: ; in, The flow rate of the cold air passing through the comb teeth. The flow loss coefficient is... The ideal gas flow rate is... It is the product of the kinetic energy transfer coefficient and the correction coefficient.

[0011] Furthermore, this embodiment of the invention provides a sixth possible implementation of the first aspect, wherein the type of the grating teeth is the oblique tooth straight-through grating teeth, and the calculation formula for the flow rate of the cold air passing through the grating teeth is: ; ; in, The flow rate of the cold air passing through the comb teeth. This is the corrected flow loss coefficient. The ideal gas flow rate is... It is the product of the kinetic energy transfer coefficient and the correction coefficient. The flow loss coefficient is... The angle between the center line of the tooth of the comb and the engine axis.

[0012] Furthermore, this embodiment of the invention provides a seventh possible implementation of the first aspect, wherein the type of the sieve teeth is the stepped sieve teeth; The formula for calculating the flow rate of cold air through the comb teeth is as follows: ; in, The flow rate of the cold air passing through the comb teeth. The flow loss coefficient is... The ideal gas flow rate is... This is a correction factor.

[0013] Furthermore, the present invention provides an eighth possible implementation of the first aspect, which further includes: The minimum dimensionless sealing airflow rate is determined based on the turbine disk rear sealing structure. The turbine disk rear sealing airflow rate is calculated based on the minimum dimensionless sealing airflow rate, disk rim radius, sealing gap size at the rim, and rear sealing air density. Based on the turbine disk rear sealing airflow rate, cold air is introduced into the turbine rear disk cavity.

[0014] Furthermore, the present invention provides a ninth possible implementation of the first aspect, wherein the total turbine outlet temperature and the total turbine outlet pressure are obtained based on a probe at the turbine outlet, the axial position of the probe is after a first preset length downstream of the rear-sealed cold air outlet, the radial position of the probe is located between the hub and the casing, and the distance from the hub is a second preset length; wherein the first preset length is related to the rotor axial chord length, and the second preset length is related to the channel height between the hub and the casing.

[0015] Secondly, embodiments of the present invention also provide a test efficiency evaluation system for an air-cooled turbine that takes into account cold air leakage, comprising: multiple measuring probes and a controller, wherein the controller includes a processor and a storage device; The controller is communicatively connected to multiple measurement probes, which are used to detect the total temperature at the turbine inlet, the total pressure at the turbine inlet, the total temperature at the turbine outlet, the total pressure at the turbine outlet, and the total temperature and pressure at the cold air inlet of the upstream sealing grate. The storage device stores a computer program that, when executed by the processor, performs the method as described in any of the first aspects.

[0016] This invention provides a method for evaluating the efficiency of an air-cooled turbine test considering cold air leakage. The method includes: detecting the total temperature and pressure at the turbine inlet, the total temperature and pressure at the turbine outlet, and conducting aerodynamic performance tests on turbine components to obtain the main gas flow rate at the turbine inlet, the turbine main gas pressure drop ratio, the turbine main gas temperature ratio, and the main gas working fluid specific heat ratio; detecting the total temperature and pressure at the cold air inlet of the upstream sealing grate to obtain the flow loss coefficient of the grate sealing; determining the cold air flow rate through the grate based on the flow loss coefficient, the total temperature and pressure at the cold air inlet; and calculating the isentropic efficiency of the air-cooled turbine test considering cold air leakage based on the cold air flow rate through the grate, the main gas flow rate, the total temperature at the turbine inlet, the total temperature at the turbine outlet, the turbine main gas pressure drop ratio, the total pressure at the turbine inlet, the total pressure at the turbine outlet, and the specific heat ratio of the working fluid. This invention calculates the flow rate of cold air through the upstream sealed grate by detecting the total temperature and pressure of the cold air inlet. Based on the flow rate of the cold air through the grate and the main gas flow rate at the turbine inlet, it calculates the isentropic efficiency of the air-cooled turbine test. It considers the impact of leakage flow in the turbine cooling system and the mixing of high-temperature gas in the main flow channel on turbine performance. The calculation of the turbine isentropic efficiency takes into account cold air leakage, which can reflect the true turbine efficiency. This solves the problem of inaccurate turbine performance evaluation results caused by not considering cold air leakage in turbine test efficiency measurement, and allows for direct comparison and selection of the best scheme during turbine design.

[0017] Other features and advantages of the embodiments of the present invention will be set forth in the following description, or some features and advantages may be inferred from the description or determined without doubt, or may be learned by practicing the techniques described above in the embodiments of the present invention.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 The flowchart of a test efficiency evaluation method for an air-cooled turbine considering cold air leakage provided by an embodiment of the present invention is shown. Figure 2 This diagram illustrates a straight-tooth straight-through grate sealing structure provided by an embodiment of the present invention; Figure 3This diagram illustrates a helical toothed straight-through grate sealing structure provided by an embodiment of the present invention. Figure 4 This diagram illustrates a stepped comb-type sealing structure provided by an embodiment of the present invention. Figure 5 This invention provides a flowchart for evaluating the test efficiency of an air-cooled turbine considering cold air leakage, as provided in an embodiment of the invention. Figure 6 A schematic diagram of a turbine with a cold airflow pattern is shown in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0022] Currently, existing industry standards stipulate that turbine test efficiency is determined by measuring turbine runout parameters. With the rapid iteration and updates of turbine generations, and the continuous increase in turbine inlet total temperature, the demand for cooling and sealing of hot-end components is becoming increasingly stringent to ensure their safe and efficient operation and the structural integrity of the engine. Cool air needs to be introduced into the turbine disk cavity to suppress the intrusion of high-temperature combustion gases into the runout. This increased demand for cool air leads to more cool air entering the turbine runout, significantly impacting turbine efficiency.

[0023] Current industry standards calculate turbine isentropic efficiency by measuring the pressure ratio and temperature ratio at the turbine inlet and outlet, and then using the ratio of rim work to isentropic expansion work. This efficiency assessment method fails to consider the impact of leakage flow in the turbine cooling system and the mixing of high-temperature combustion gases in the main flow path on turbine performance, thus failing to reflect true turbine efficiency and hindering comprehensive comparisons of turbine design schemes. Some experimental studies have attempted to incorporate the impact of bleed air on turbine isentropic efficiency, using this as an input to estimate the amount of bleed air required. However, the significant increase in turbine inlet temperature in modern aero-engines leads to an increase in bleed air volume. Estimating the amount of bleed air in this way cannot reflect the actual amount of bleed air used. Furthermore, bleed air is also required downstream of the rotor disk for sealing; this bleed air does not participate in the turbine expansion work process but affects the measurement of downstream aerodynamic parameters of the turbine rotor. Therefore, it is difficult to obtain true turbine efficiency using conventional methods.

[0024] To address the aforementioned issues, this invention provides a method for evaluating the test efficiency of an air-cooled turbine that takes into account cold air leakage. The following provides a detailed description of this invention.

[0025] This embodiment provides a method for evaluating the test efficiency of an air-cooled turbine considering cold air leakage. This method can be applied to electronic devices such as computers. See [link to documentation]. Figure 1The flowchart shown illustrates a test efficiency evaluation method for air-cooled turbines considering cold air leakage. This method mainly includes the following steps: Step S102: Detect the total temperature at the turbine inlet, the total pressure at the turbine inlet, the total temperature at the turbine outlet, and the total pressure at the turbine outlet; conduct aerodynamic performance tests on turbine components; and obtain the main gas flow rate at the turbine inlet, the turbine main gas pressure drop ratio, the turbine main gas temperature ratio, and the main gas working fluid specific heat ratio. Measuring probes were installed at the turbine inlet and turbine outlet of the test apparatus, and the total temperature at the turbine inlet was measured based on the measuring probes. Turbine inlet static temperature Turbine inlet total pressure Turbine inlet static pressure Turbine outlet total temperature and turbine outlet total pressure .

[0026] By using a virtual turbine aerodynamic performance testing system, the aerodynamic performance of turbine components can be tested, and the power P and the main air flow rate at the turbine inlet can be obtained. Turbine main air pressure ratio Turbine main air temperature ratio Specific heat ratio of main working gas Specific heat at constant pressure of the main working gas Turbine main air pressure ratio Total pressure at the turbine inlet Total pressure at turbine outlet The ratio of turbine main air temperature ratio Turbine inlet total temperature Total temperature at turbine outlet The ratio of .

[0027] In one embodiment, the measuring probes for total temperature and total pressure installed at the turbine inlet and turbine outlet can be arranged circumferentially according to the guide vane pitch, with the number of probes not exceeding 6; each probe should measure 6 to 9 points radially. The installation cross-section of the turbine outlet total pressure probe can be flexibly adjusted according to the specific conditions of the test specimen. The measurement position of the turbine outlet probe should avoid the influence of the cold air behind the disc that does not participate in the turbine's work, and the length of the forward-extending part of the probe head support must be considered to avoid the probe rubbing against the rotor blades.

[0028] Step S104: Detect the total temperature and total pressure of the cold air inlet at the upstream sealing grate, obtain the flow loss coefficient of the grate sealing, and determine the flow rate of the cold air passing through the grate based on the flow loss coefficient, the total temperature and total pressure of the cold air inlet. Measuring probes are installed at the sealed inlet and outlet of the cold air intake duct upstream. The total pressure at the cold air inlet is measured using these probes. Total temperature at the air inlet Static pressure at the air outlet The gap between the tooth tip and the tooth bushing , where subscript This indicates the number of the upstream cooling unit.

[0029] The measuring probes at the inlet and outlet of the upstream sealing grate can be set in the stator bushing, and the gap measuring instrument is placed in the stator bushing and aligned with the tip of the grate.

[0030] The flow loss coefficient of the toothed seal was determined through simulation or principle-based tests. Based on flow loss coefficient Total temperature at the air inlet and total pressure of cold air inlet Calculate the flow rate of cold air through the comb teeth Based on the flow path diagram of the turbine air system and the pressure relationship on both sides of the grate, the flow rate of the cold air not entering the main air passage is set to... To ensure high accuracy in turbine efficiency measurement, the turbine main gas flow rate measurement accuracy should be above ±0.5%. Measurements of other parameters such as temperature and pressure can be performed according to industry practice.

[0031] Step S106: Calculate the isentropic efficiency of the air-cooled turbine test considering cold gas leakage based on the cold gas flow rate through the grate, main gas flow rate, turbine inlet total temperature, cold gas inlet total temperature, turbine main gas temperature ratio, turbine outlet total temperature, turbine main gas pressure ratio, cold gas inlet total pressure, turbine outlet total pressure, and gas working fluid specific heat ratio.

[0032] Based on the detected total temperature of the cold air inlet and total pressure of cold air inlet Calculate the temperature ratio and the pressure drop ratio of the cooling air, where the temperature ratio of the cooling air is... Total temperature at the air inlet Total temperature at turbine outlet The ratio of the cooling air pressure ratio Total pressure at the cold air inlet Total pressure at turbine outlet The ratio, based on the cooling air pressure ratio. The temperature ratio of the air conditioner Flow rate of cold air through the comb Main air flow rate at turbine inlet Turbine main air pressure ratio Compared with turbine main air temperature Calculate the isentropic efficiency of an air-cooled turbine test considering cold air leakage. .

[0033] The air-cooled turbine test efficiency evaluation method considering cold air leakage provided in this embodiment calculates the cold air flow rate through the grate by detecting the total temperature and total pressure of the cold air inlet at the upstream sealing grate, and then calculates the isentropic efficiency of the air-cooled turbine test based on the cold air flow rate through the grate and the main gas flow rate at the turbine inlet. This method considers the impact of leakage flow in the turbine cooling system and high-temperature gas mixing in the main flow channel on turbine performance. By taking cold air leakage into account in the calculation of turbine isentropic efficiency, it can reflect the true turbine efficiency and solve the problem of inaccurate turbine performance evaluation results caused by not considering cold air leakage in turbine test efficiency measurement. This allows for direct comparison and selection of the best option among different schemes during turbine design.

[0034] In one embodiment, this embodiment provides a specific implementation method for calculating the isentropic efficiency of an air-cooled turbine test considering cold gas leakage based on the cold gas flow rate through the grate, main gas flow rate, turbine inlet total temperature, cold gas inlet total temperature, turbine main gas temperature ratio, turbine outlet total temperature, turbine main gas pressure drop ratio, cold gas inlet total pressure, turbine outlet total pressure, and gas specific heat ratio: Calculate the ratio of the total inlet temperature of the cold air to the total outlet temperature of the turbine to obtain the temperature ratio of the cold air; Calculate the ratio of the total pressure at the cold air inlet to the total pressure at the turbine outlet to obtain the cold air pressure drop ratio; The isentropic efficiency of an air-cooled turbine test considering cold air leakage is calculated based on the cold air temperature ratio, cold air pressure ratio, cold air flow rate through the grate, main air flow rate, turbine inlet total temperature, cold air inlet total temperature, turbine main air temperature ratio, turbine main air pressure ratio, and gas specific heat ratio.

[0035] In one specific implementation, the formula for calculating the isentropic efficiency of an air-cooled turbine test considering cold air leakage is as follows:

[0036] in, This refers to the total temperature at the turbine inlet. This is the total temperature at the air inlet. The turbine main temperature ratio, The temperature ratio of the air conditioner. Main air flow, The airflow rate through the comb teeth. This refers to the turbine main air pressure ratio. This refers to the pressure drop ratio of the cold air. The specific heat ratio of the main gas working fluid This refers to the upstream cold air unit; the temperature ratio of the cold air unit is related to the total temperature at the cold air inlet and the total temperature at the turbine outlet, while the pressure drop ratio of the cold air unit is related to the total pressure at the cold air inlet and the total pressure at the turbine outlet.

[0037] In one embodiment, the steps for determining the main airflow volume include: The turbine inlet static pressure and turbine inlet static temperature are detected. The Mach number is determined based on the turbine inlet static pressure, turbine inlet total pressure and gas dynamic functions. The average velocity of the turbine inlet airflow is calculated based on the Mach number and turbine inlet static temperature. The turbine inlet flow rate is calculated based on the average velocity and the turbine inlet cross-sectional area to obtain the main gas flow rate.

[0038] The main gas flow rate is obtained through the following gas dynamics function:

[0039] in, Represents the average parameter. The static pressure at the turbine inlet can be directly averaged at different circumferential positions on the casing. The total pressure at the turbine inlet can be averaged at radially equal torsion surface positions. Mach number, The specific heat ratio of the main gas working fluid; according to Calculate the average velocity, and then through The turbine inlet flow rate, i.e. the main gas flow rate, is calculated.

[0040] in, Let be the ideal gas constant. For turbine inlet static temperature, This represents the cross-sectional area of ​​the turbine inlet.

[0041] In one embodiment, this embodiment provides a specific implementation method for determining the flow rate of cold air passing through the comb teeth based on the flow loss coefficient, the total temperature of the cold air inlet, and the total pressure of the cold air inlet: The ideal gas flow rate is determined based on the flow function of the pylon seal, the total temperature at the cold air inlet, and the total pressure at the cold air inlet. The flow rate of cold air passing through the grate is determined based on the type of grate teeth, the ideal gas flow rate, and the flow loss coefficient; among which, the types of grate teeth include straight-through grate teeth, helical straight-through grate teeth, and stepped grate teeth.

[0042] Flow loss coefficient The aerodynamic loss coefficient of the aforementioned straight-through toothed grating can be obtained through experimentation or simulation. In one embodiment, the coefficient is... The loss coefficient after correction of the inclination angle of the helical toothed straight-through grate seal is approximately 0.66. The aerodynamic loss coefficient for stepped grates needs to be obtained through grate sealing tests or simulations. and correction factor .

[0043] The flow function for the toothed seal can be defined using the Martin formula:

[0044] in, The number of teeth on the comb. For the flow function of the toothed seal, The pressure drop ratio of the cold air; the ideal gas flow rate is:

[0045] in, This represents the annular area at the gap between the teeth. This refers to the total pressure at the turbine inlet. The total temperature at the cold air inlet is the total temperature. The flow velocity upstream of the grate is generally low. The total parameters can be replaced by the measured static parameters. That is, the total pressure at the turbine inlet can be replaced by the static pressure at the turbine inlet, and the total temperature at the cold air inlet can be replaced by the static temperature at the cold air inlet.

[0046] In one embodiment, see as follows Figure 2 The schematic diagram shown is of a straight-tooth, through-type grate sealing structure. In this embodiment, the grate type is a straight-tooth grate. The formula for calculating the flow rate of cold air through the grate is: ; in, The airflow rate through the comb teeth. This is the flow loss coefficient. For ideal gas flow rate, The kinetic energy transfer coefficient With correction factor The product of.

[0047]

[0048]

[0049] in, The tooth pitch is the axial distance between the center lines of the two tooth tips. It is generally taken as around 0.66; This refers to the gap between the tooth tips of the grate rotor and the grate stator bushing.

[0050] In one embodiment, see as follows Figure 3 The schematic diagram shown is of a helical toothed straight-through grate sealing structure. In this embodiment, the grate type is a helical toothed straight-through grate. The formula for calculating the flow rate of cold air through the grate is: ; For helical toothed straight-through toothed sealing, the loss coefficient needs to be adjusted. The tooth tilt angle is corrected, and the corrected loss coefficient is: ; in, The airflow rate through the comb teeth. This is the corrected flow loss coefficient. For ideal gas flow rate, It is the product of the kinetic energy transfer coefficient and the correction coefficient. This is the flow loss coefficient. The angle between the center line of the tooth of the comb and the engine axis.

[0051] In one embodiment, see as follows Figure 4 The schematic diagram shown is of a stepped tooth sealing structure. In this embodiment, the tooth type is a stepped tooth. The formula for calculating the flow rate of cold air through the comb teeth is: ; in, The airflow rate through the comb teeth. This is the flow loss coefficient. For ideal gas flow rate, This is a correction factor.

[0052] The above correction coefficient for The function, The width of the tooth tip of the comb; The gap between the tooth tip of the grate rotor and the grate stator bushing is the flow loss coefficient in the calculation formula for the cold airflow of a stepped grate. The loss coefficient for a single tooth can be taken.

[0053] In one embodiment, the method provided in this embodiment further includes: The minimum dimensionless sealing airflow rate is determined based on the turbine disk rear sealing structure. The turbine disk rear sealing airflow rate is calculated based on the minimum dimensionless sealing airflow rate, disk rim radius, sealing gap size at the rim, and rear sealing air density. Based on the turbine disk rear sealing airflow rate, cold air is introduced into the turbine rear disk cavity.

[0054] To ensure the lifespan of the turbine disk, cool air is introduced into the rear disk cavity. For high-pressure turbines, the minimum dimensionless sealing cool air flow rate is determined using the following formula:

[0055] in, Related to the sealing structure, commonly used axial seals ,Right now . The rotor angular velocity, Let be the radius of the disc rim.

[0056] Through formula The required back-panel airflow for complete sealing was calculated, where, The density of cold air behind the plate. This refers to the sealing clearance dimension at the rim.

[0057] The above-mentioned turbine disk back sealing airflow has an upper boundary value and a lower boundary value. The upper boundary value is set to ensure that the turbine efficiency measurement accuracy is not affected. The lower boundary value is the minimum dimensionless sealing cold air flow rate. The turbine disk back sealing airflow rate should be as close as possible to the lower boundary value to ensure the minimum sealing air flow rate and thus ensure the life of the turbine tester.

[0058] In one embodiment, the total turbine outlet temperature and total turbine outlet pressure provided in this embodiment are obtained based on a probe at the turbine outlet. The axial position of the probe is a first preset length downstream of the cold air outlet behind the disc seal, and the radial position of the probe is between the hub and the casing, and the distance from the hub is a second preset length. The first preset length is related to the axial chord length of the rotor, and the second preset length is related to the height of the channel between the hub and the casing.

[0059] To avoid the probe measurement position being affected by the cold air behind the disk that does not participate in the turbine's work, the probe's axial position is located downstream of the cold air outlet sealed behind the disk, and the distance between the probe and the cold air outlet sealed behind the disk is greater than a first preset length. The first preset length can be greater than or equal to the rotor's axial chord length, and the value of the second preset length can be within the range of the channel height. 30%~Channel height 40%, preferred channel height 35%.

[0060] In one embodiment, the axial position of the probe can be after a first preset length (rotor axial chord length) downstream of the rear-sealed cold air outlet, and the radial position is between the hub and the casing at a distance of 35% of the channel height. At least 6 radial measuring points at the turbine outlet are arranged based on the assumption of equal toroidal surfaces, and no less than 5 probe positions are arranged circumferentially at the turbine outlet. The total temperature and total pressure at the turbine outlet are calculated by averaging the test results after multiple probe measurements.

[0061] The air-cooled turbine test efficiency evaluation method considering cold air leakage provided in this embodiment can effectively ensure the lifespan of the turbine tester by providing the airflow consumption at the turbine disk back seal and the limiting conditions of the downstream measuring points of the turbine, so that the measurement results can reflect the true turbine performance. By measuring the temperature, pressure and clearance at the grate seal, the relationship between flow rate and aerodynamic geometric parameters is established, thereby obtaining the accurate cold air flow rate entering the turbine mainstream channel through the air system. In the process of calculating the turbine isentropic efficiency, the cold air enthalpy drop is introduced, thereby obtaining the true turbine test efficiency. This solves the problem of inaccurate turbine performance evaluation results caused by not considering cold air leakage in turbine test efficiency measurement, and allows for direct comparison and selection of the best scheme in the turbine design process.

[0062] Based on the foregoing embodiments, see as follows: Figure 5The flowchart shown illustrates the evaluation process for air-cooled turbine testing considering cold air leakage. This embodiment provides an example of applying the aforementioned evaluation method for air-cooled turbine testing considering cold air leakage. The specific steps are as follows: Step S501: Install measuring probes at the turbine inlet and turbine outlet of the test apparatus to measure the total temperature at the turbine inlet. Turbine inlet static temperature Turbine inlet total pressure Turbine inlet static pressure Turbine outlet total temperature and turbine outlet total pressure .

[0063] Step S502: Install measuring probes at the inlet and outlet of the sealed grate upstream of the cold air supply to measure the total pressure at the cold air inlet. Total temperature at the air inlet Static pressure at the air outlet The gap between the tooth tip and the tooth bushing .

[0064] The above subscript Indicates the upstream air conditioning unit number, see example... Figure 6 The diagram shown is a schematic of a turbine containing a cold airflow pattern. Figure 6 The diagram shows the airflow path ① of the first stream of cold air and the airflow path ② of the second stream of cold air, i.e., the numbering of the upstream cold air. The value can be either 1 or 2.

[0065] Step S503: Conduct aerodynamic performance tests on the turbine components to obtain the power P and the main air flow rate at the turbine inlet. Turbine main air pressure ratio Turbine main air temperature ratio Specific heat ratio of main working gas Specific heat at constant pressure of the main working gas .

[0066] Among them, the turbine main air pressure ratio Total pressure at the turbine inlet Total pressure at turbine outlet The ratio of turbine main air temperature ratio Turbine inlet total temperature Total temperature at turbine outlet The ratio of .

[0067] Step S504: Determine the flow loss coefficient of the toothed seal through simulation or principle experiment. .

[0068] Step S505, based on the flow parameters of the grate teeth and the flow loss coefficient of the grate teeth sealing. The flow rate of cold air passing through the comb teeth is calculated. ; Based on the flow path diagram of the turbine air system and the pressure relationship on both sides of the comb, the flow rate of the cold air not entering the main air passage can be set to... ; Step S506: Calculate the cooling air pressure ratio based on the turbine and grate flow parameters measured in steps S501 and S502. Compared to the temperature of air conditioning ; Among them, the pressure drop ratio of the cold air Total pressure at the cold air inlet Total pressure at turbine outlet The ratio of the total inlet temperature of the cold air is the temperature ratio of the cold air. Total temperature at turbine outlet The ratio.

[0069] Step S507: Based on the results of steps S503 and S505, calculate the isentropic efficiency of the air-cooled turbine test considering cold air leakage. .

[0070]

[0071] in, This refers to the total temperature at the turbine inlet. This is the total temperature at the air inlet. The turbine main temperature ratio, The temperature ratio of the air conditioner. Main air flow, The airflow rate through the comb teeth. This refers to the turbine main air pressure ratio. This refers to the pressure drop ratio of the cold air. The specific heat ratio of the main gas working fluid This refers to the upstream cold air unit; the temperature ratio of the cold air unit is related to the total temperature at the cold air inlet and the total temperature at the turbine outlet, while the pressure drop ratio of the cold air unit is related to the total pressure at the cold air inlet and the total pressure at the turbine outlet.

[0072] Corresponding to the air-cooled turbine test efficiency evaluation method considering cold air leakage provided in the above embodiments, the present invention provides an air-cooled turbine test efficiency evaluation system considering cold air leakage. The system includes: multiple measurement probes and a controller, wherein the controller includes a processor and a storage device; The controller is communicatively connected to multiple measurement probes, which are used to detect the total temperature at the turbine inlet, the total pressure at the turbine inlet, the total temperature at the turbine outlet, the total pressure at the turbine outlet, and the total temperature and pressure at the cold air inlet of the upstream sealing grate. The storage device stores a computer program, which, when run by the processor, executes the air-cooled turbine test efficiency evaluation method considering cold air leakage provided in the above embodiments.

[0073] The system provided in this embodiment has the same implementation principle and technical effects as the aforementioned embodiments. For the sake of brevity, any parts not mentioned in the system embodiment can be referred to the corresponding content in the aforementioned method embodiment.

[0074] This invention provides a computer-readable medium storing computer-executable instructions. When these computer-executable instructions are invoked and executed by a processor, they cause the processor to implement the methods described in the above embodiments.

[0075] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the system described above can be referred to the corresponding process in the foregoing embodiments, and will not be repeated here.

[0076] The computer program product of the air-cooled turbine test efficiency evaluation method considering cold air leakage provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the preceding method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

[0077] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0078] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0079] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0080] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for evaluating the test efficiency of an air-cooled turbine considering cold air leakage, characterized in that, include: The turbine inlet total temperature, turbine inlet total pressure, turbine outlet total temperature and turbine outlet total pressure are measured, and the aerodynamic performance of the turbine components is tested to obtain the main gas flow rate at the turbine inlet, the turbine main gas pressure ratio, the turbine main gas temperature ratio and the main gas working fluid specific heat ratio. The total temperature and total pressure of the cold air inlet at the upstream sealing grate are detected to obtain the flow loss coefficient of the grate sealing. Based on the flow loss coefficient, the total temperature and total pressure of the cold air inlet, the flow rate of the cold air flowing through the grate is determined. The isentropic efficiency of the air-cooled turbine test considering cold gas leakage is calculated based on the cold gas flow rate through the grates, the main gas flow rate, the total temperature at the turbine inlet, the total temperature at the cold gas inlet, the turbine main gas temperature ratio, the total temperature at the turbine outlet, the turbine main gas pressure ratio, the total pressure at the cold gas inlet, the total pressure at the turbine outlet, and the specific heat ratio of the working fluid.

2. The method according to claim 1, characterized in that, The step of calculating the isentropic efficiency of the air-cooled turbine test considering cold gas leakage based on the cold gas flow rate through the grates, the main gas flow rate, the turbine inlet total temperature, the cold gas inlet total temperature, the turbine main gas temperature ratio, the turbine outlet total temperature, the turbine main gas pressure drop ratio, the cold gas inlet total pressure, the turbine outlet total pressure, and the specific heat ratio of the working fluid includes: The ratio of the total inlet temperature of the cold air to the total outlet temperature of the turbine is calculated to obtain the temperature ratio of the cold air. Calculate the ratio of the total pressure at the cold air inlet to the total pressure at the turbine outlet to obtain the cold air pressure drop ratio; The isentropic efficiency of the air-cooled turbine test considering cold gas leakage is calculated based on the temperature ratio of the cold gas, the pressure ratio of the cold gas, the flow rate of the cold gas flowing through the grates, the main gas flow rate, the total temperature of the turbine inlet, the total temperature of the cold gas inlet, the temperature ratio of the turbine main gas, the pressure ratio of the turbine main gas, and the specific heat ratio of the working fluid.

3. The method according to claim 1, characterized in that, The formula for calculating the isentropic efficiency of the air-cooled turbine test is as follows: in, The total temperature at the turbine inlet. The total temperature of the cold air inlet. The turbine main air temperature ratio, The temperature ratio of the air conditioner. The main gas flow rate is... The flow rate of the cold air passing through the comb teeth. The turbine main air pressure ratio is... This refers to the pressure drop ratio of the cold air. The specific heat ratio of the main gas working fluid. The upstream cold air is designated as a number; the temperature ratio of the cold air is related to the total temperature at the cold air inlet and the total temperature at the turbine outlet, and the pressure drop ratio of the cold air is related to the total pressure at the cold air inlet and the total pressure at the turbine outlet.

4. The method according to claim 1, characterized in that, The step of determining the flow rate of the cold air passing through the comb teeth based on the flow loss coefficient, the total temperature of the cold air inlet, and the total pressure of the cold air inlet includes: The ideal gas flow rate is determined based on the flow function of the pylon seal, the total temperature of the cold air inlet, and the total pressure of the cold air inlet. The flow rate of cold air passing through the grate teeth is determined based on the type of the grate teeth, the ideal gas flow rate, and the flow loss coefficient; wherein, the type of the grate teeth includes straight-through grate teeth, helical straight-through grate teeth, and stepped grate teeth.

5. The method according to claim 4, characterized in that, The type of the grating teeth is the straight-through type, and the formula for calculating the flow rate of the cold air passing through the grating teeth is: ; in, The flow rate of the cold air passing through the comb teeth. The flow loss coefficient is... The ideal gas flow rate is... It is the product of the kinetic energy transfer coefficient and the correction coefficient.

6. The method according to claim 4, characterized in that, The type of the grating teeth is the oblique tooth straight-through grating teeth, and the formula for calculating the flow rate of the cold air passing through the grating teeth is: ; ; in, The flow rate of the cold air passing through the comb teeth. This is the corrected flow loss coefficient. The ideal gas flow rate is... It is the product of the kinetic energy transfer coefficient and the correction coefficient. The flow loss coefficient is... The angle between the center line of the tooth of the comb and the engine axis.

7. The method according to claim 4, characterized in that, The type of the comb teeth is the stepped comb teeth; The formula for calculating the flow rate of cold air through the comb teeth is as follows: ; in, The flow rate of the cold air passing through the comb teeth. The flow loss coefficient is... The ideal gas flow rate is... This is a correction factor.

8. The method according to claim 1, characterized in that, Also includes: The minimum dimensionless sealing airflow rate is determined based on the turbine disk rear sealing structure. The turbine disk rear sealing airflow rate is calculated based on the minimum dimensionless sealing airflow rate, disk rim radius, sealing gap size at the rim, and rear sealing air density. Based on the turbine disk rear sealing airflow rate, cold air is introduced into the turbine rear disk cavity.

9. The method according to claim 1, characterized in that, The total temperature and total pressure at the turbine outlet are obtained based on measurements taken by a probe at the turbine outlet. The axial position of the probe is a first preset length downstream of the cold air outlet sealed behind the disc, and the radial position of the probe is located between the hub and the casing, with a distance of a second preset length from the hub. The first preset length is related to the axial chord length of the rotor, and the second preset length is related to the height of the channel between the hub and the casing. And / or, The steps for determining the main airflow volume include: The turbine inlet static pressure and turbine inlet static temperature are detected. The Mach number is determined based on the turbine inlet static pressure, the turbine inlet total pressure, and a gas dynamics function. The average velocity of the turbine inlet airflow is calculated based on the Mach number and the turbine inlet static temperature. The turbine inlet flow rate is calculated based on the average velocity and turbine inlet cross-sectional area to obtain the main gas flow rate.

10. A test efficiency evaluation system for an air-cooled turbine considering cold air leakage, characterized in that, include: Multiple measurement probes and a controller, wherein the controller includes a processor and a storage device; The controller is communicatively connected to multiple measurement probes, which are used to detect the total temperature at the turbine inlet, the total pressure at the turbine inlet, the total temperature at the turbine outlet, the total pressure at the turbine outlet, and the total temperature and pressure at the cold air inlet of the upstream sealing grate. The storage device stores a computer program that, when executed by the processor, performs the method as described in any one of claims 1 to 9.

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