阅读说明：本技术 一种低压比轴流压缩机模型级级性能计算方法 (Low-pressure-ratio axial flow compressor model level performance calculation method ) 是由 段纪成 史军党 程凯 周向民 田玉宝 毛若明 李晓辉 于 2020-03-27 设计创作，主要内容包括：本发明提供了一种低压比轴流压缩机模型级级性能计算方法,该方法按照以下步骤进行：步骤一,采集参数：采集轴流压缩机模型级的环境参数、流量参数、进口参数、出口参数和前期准备参数；步骤二,计算三级轴流压缩机模型级的整体性能参数：整体能量头和整体多变效率；步骤三,获取各级各级能量头比例系数和多变效率比例系数：步骤四,各级的级性能参数的分级计算：根据各级多变效率比例系数和各级能量头比例系数,对步骤二获得的三级轴流压缩机模型级的整体性能参数进行逐级分解。本发明通过多级整体试验,各级分解计算和数值模拟的结合获取相对准确的能够指导工业应用的轴流压缩机模型级单级性能参数。(The invention provides a method for calculating the performance of a low-pressure ratio axial flow compressor model level, which comprises the following steps: step one, collecting parameters: collecting model-level environmental parameters, flow parameters, inlet parameters, outlet parameters and early-stage preparation parameters of the axial flow compressor; step two, calculating the integral performance parameters of the model level of the three-level axial flow compressor: the whole energy head and the whole variable efficiency; step three, acquiring the proportional coefficients of the energy heads and the variable efficiency of each stage: step four, calculating the grade performance parameters of each grade in a grading way: and step-by-step decomposition is carried out on the overall performance parameters of the three-stage axial flow compressor model stage obtained in the step two according to the variable efficiency proportionality coefficients of the stages and the energy head proportionality coefficients of the stages. According to the method, through a multi-stage overall test, the combination of decomposition calculation and numerical simulation at each stage is used for obtaining relatively accurate single-stage performance parameters of the axial flow compressor model stage capable of guiding industrial application.)

1. A method for calculating the performance of a low-pressure-ratio axial flow compressor model level is characterized in that the axial flow compressor model level is a three-level axial flow compressor model level, and the three-level axial flow compressor model level is divided into a first level, a second level and a third level, and the method is carried out according to the following steps:

step one, collecting parameters:

collecting the environmental parameters, the flow parameters, the inlet parameters, the outlet parameters and the early-stage preparation parameters of the model level of the axial flow compressor, wherein:

environmental parameters: pa is atmospheric pressure in kPa; ta is the atmospheric temperature in K;

flow parameters: q_mIs mass flow rate, and the unit is kg/s;

the inlet parameters are as follows: p_1stIs the total inlet pressure in kPa; p_1sInlet static pressure in kPa; t is_1pIs the effective temperature at the inlet, in K;

and (3) outlet parameters: p_2stIs the total outlet pressure in kPa; p_2sOutlet static pressure in kPa; t is_2pIs the exit effective temperature in K;

preparing parameters at the early stage: k is adiabatic index, and k is 1.4; r is a gas constant, and R is 288.3J/(kg K); a. the₁Is the flow area of the inlet channel, and the unit is m²；A₂Is the flow area of the outlet flow passage, and the unit is m²(ii) a Gamma is the recovery coefficient of the temperature transmitter corresponding to the effective temperature of the inlet and the effective temperature of the outlet;

step two, calculating the integral performance parameters of the model level of the three-level axial flow compressor:

the whole energy head:

overall polytropic efficiency:

wherein:

total inlet temperature:

inlet static temperature:

square of inlet mach number:

average velocity of inlet airflow:

inlet density:

total outlet temperature:

outlet static temperature:

square of exit mach number:

average velocity of outlet gas flow:

outlet density:

integral pressure ratio:

step three, acquiring the proportional coefficients of the energy heads and the variable efficiency of each stage:

inputting the parameters collected in the step one into a numerical simulation software, establishing a simulation model of a model level of the three-level axial flow compressor, and carrying out numerical simulation on the simulation model of the model level of the three-level axial flow compressor to enable the difference between the simulation calculation result of the overall energy head of the simulation model and the overall energy head obtained in the step two to be within 2% and enable the difference between the simulation calculation result of the overall polytropic efficiency of the simulation model and the overall polytropic efficiency obtained in the step two to be within 2%;

then, obtaining the simulation calculation results of all levels of variable efficiency and the simulation calculation results of all levels of energy heads of the simulation model of the three-level axial flow compressor model level in the numerical simulation software, and then obtaining the proportional coefficients of all levels of variable efficiency and the proportional coefficients of all levels of energy heads according to the following constraint conditions:

λ₁+λ₂+λ₃＝1；h'_1pol+h'_2pol+h'_3pol＝h'_pol；

wherein:

λ₁、λ₂and λ₃Respectively a first-level energy head proportionality coefficient, a second-level energy head proportionality coefficient and a third-level energy head proportionality coefficient;

h'_1pol，h'_2pol，h'_3pol，h'_polrespectively obtaining a first-level energy head simulation calculation result, a second-level energy head simulation calculation result, a third-level energy head simulation calculation result and an overall energy head simulation calculation result through numerical simulation calculation in numerical simulation software;

μ₁，μ₂and mu₃Respectively a first-level variable efficiency proportionality coefficient, a second-level variable efficiency proportionality coefficient and a third-level variable efficiency proportionality coefficient;

η'_1pol,η'_2pol,η'_3pol，η'_polrespectively obtaining a first-stage variable efficiency simulation calculation result, a second-stage variable efficiency simulation calculation result, a third-stage variable efficiency simulation calculation result and integral variable efficiency through numerical simulation calculation in numerical simulation softwareA rate simulation calculation result;

step four, calculating the grade performance parameters of each grade in a grading way:

and step-by-step decomposition is carried out on the overall performance parameters of the three-level axial flow compressor model stage obtained in the step two according to the variable efficiency proportionality coefficients of all levels and the energy head proportionality coefficients of all levels:

first-order energy head: h is_1pol＝λ₁h_polη first-stage variable efficiency_1pol＝μ₁η_pol；

Secondary energy head: h is_2pol＝λ₂h_polη second-stage variable efficiency_2pol＝μ₂η_pol；

Third-level energy head: h is_3pol＝λ₃h_polη three-stage variable efficiency_3pol＝μ₃η_pol。

Technical Field

The invention belongs to the field of axial flow compressors, relates to a low-pressure-ratio axial flow compressor model level, and particularly relates to a low-pressure-ratio axial flow compressor model level performance calculation method.

Background

The axial flow compressor is widely applied to the industrial fields of metallurgy, petrochemical industry and the like. With the requirements of large-scale, high pressure and high efficiency of the unit, the requirements on technical indexes of the unit, such as energy consumption, reliability, matching level and the like, are higher and higher. A novel efficient axial flow compressor unit is developed, and a test is an insurmountable important link. The axial flow compressor model level test, especially the single-level model level with small pressure rise and temperature rise, has large flow, small temperature rise and large technical difficulty, and the test precision hardly meets the application requirement. Due to the limitation of the technical development, the reliability of the calculation result of the numerical simulation is difficult to reach the industrial application level.

At present, the axial compressor model level test has the following types:

single-stage test: comb-tooth (or rake) total temperature and total pressure probes are arranged in an inlet runner and an outlet runner of a single-stage model of the axial flow compressor to test thermodynamic parameters of the axial flow compressor to obtain performance parameters of the axial flow compressor.

And (3) multi-stage test: comb-tooth (or rake) total temperature and total pressure probes are arranged in a model stage inlet and an interstage runner of the axial flow compressor to test the thermal parameters of the tested stage to obtain single-stage performance parameters.

The single-stage test is limited by the precision of the instrument due to small temperature rise, and the test error is very large. Even if a torque meter is used for power measurement, the equivalent test or estimation is difficult to realize due to bearing loss, mechanical friction loss, air flow heat loss and the like, and the reliability of the test result is difficult to improve. And the correction of the mutual influence between stages of the results of the single-stage test under the actual multi-stage application working condition is also a technical difficulty.

In the multi-stage test, in order to acquire interstage flow field data, a plurality of sets of probes need to be arranged or comb-tooth probes need to be used for channel scanning. Due to space limitation, the inter-stage distance is required to be increased artificially when the comb-tooth-shaped probes are arranged, so that the internal flow field is changed, and the difference between the model-stage flow field and the flow field of an actual application product exists. At the same time. Because the comb-tooth probe is difficult to make smaller, the insertion of the probe into the flow channel can also interfere with the model-level internal flow field.

No matter single-stage test or multi-stage test, in order to obtain the performance of a single stage (or each stage) of the axial flow compressor model stage, related test points are arranged at an inlet and an outlet of the stage, and the problem of large test error caused by small pressure rise and small temperature rise of the axial flow single stage cannot be solved. For example, when the temperature rise of a single stage of the axial flow compressor is 5-15 ℃, the total error of a conventional temperature measurement transmitter is 0.5 ℃, at this time, the error of temperature measurement is relatively large, and if the power or efficiency of the axial flow compressor is calculated according to the temperature rise, the error can reach 8-10% at most.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for calculating the performance of a low-pressure ratio axial flow compressor model stage, and solve the technical problem that the single-stage performance parameters obtained in the prior art are not accurate.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for calculating the performance of a low-pressure-ratio axial flow compressor model level is characterized in that the axial flow compressor model level is a three-level axial flow compressor model level, and the three-level axial flow compressor model level is divided into a first level, a second level and a third level, and the method is carried out according to the following steps:

step one, collecting parameters:

collecting the environmental parameters, the flow parameters, the inlet parameters, the outlet parameters and the early-stage preparation parameters of the model level of the axial flow compressor, wherein:

environmental parameters: pa is atmospheric pressure in kPa; ta is the atmospheric temperature in K;

flow parameters: q_mIs mass flow rate, and the unit is kg/s;

the inlet parameters are as follows: p_1stIs the total inlet pressure in kPa; p_1sInlet static pressure in kPa; t is_1pIs the effective temperature at the inlet, in K;

and (3) outlet parameters: p_2stIs the total outlet pressure in kPa; p_2sOutlet static pressure in kPa; t is_2pIs the exit effective temperature in K;

preparing parameters at the early stage: k is adiabatic index, and k is 1.4; r is a gas constant, and R is 288.3J/(kg K); a. the₁Is the flow area of the inlet channel, and the unit is m²；A₂Is the flow area of the outlet flow passage, and the unit is m²(ii) a Gamma is the recovery coefficient of the temperature transmitter corresponding to the effective temperature of the inlet and the effective temperature of the outlet;

step two, calculating the integral performance parameters of the model level of the three-level axial flow compressor:

the whole energy head:

overall polytropic efficiency:

wherein:

total inlet temperature:

inlet static temperature:

square of inlet mach number:

average velocity of inlet airflow:

inlet density:

total outlet temperature:

outlet static temperature:

square of exit mach number:

average velocity of outlet gas flow:

outlet density:

integral pressure ratio:

step three, acquiring the proportional coefficients of the energy heads and the variable efficiency of each stage:

inputting the parameters collected in the step one into a numerical simulation software, establishing a simulation model of a model level of the three-level axial flow compressor, and carrying out numerical simulation on the simulation model of the model level of the three-level axial flow compressor to enable the difference between the simulation calculation result of the overall energy head of the simulation model and the overall energy head obtained in the step two to be within 2% and enable the difference between the simulation calculation result of the overall polytropic efficiency of the simulation model and the overall polytropic efficiency obtained in the step two to be within 2%;

then, obtaining the simulation calculation results of all levels of variable efficiency and the simulation calculation results of all levels of energy heads of the simulation model of the three-level axial flow compressor model level in the numerical simulation software, and then obtaining the proportional coefficients of all levels of variable efficiency and the proportional coefficients of all levels of energy heads according to the following constraint conditions:

λ₁+λ₂+λ₃＝1；h′_1pol+h′_2pol+h′_3pol＝h′_pol；

wherein:

λ₁、λ₂and λ₃Respectively a first-level energy head proportionality coefficient, a second-level energy head proportionality coefficient and a third-level energy head proportionality coefficient;

h′_1pol，h′_2pol，h′_3pol，h′_polrespectively obtaining a first-level energy head simulation calculation result, a second-level energy head simulation calculation result, a third-level energy head simulation calculation result and an overall energy head simulation calculation result through numerical simulation calculation in numerical simulation software;

μ₁，μ₂and mu₃Respectively a first-level variable efficiency proportionality coefficient, a second-level variable efficiency proportionality coefficient and a third-level variable efficiency proportionality coefficient;

η′_1pol,η′_2pol,η′_3pol，η′_polrespectively obtaining a first-stage variable efficiency simulation calculation result, a second-stage variable efficiency simulation calculation result, a third-stage variable efficiency simulation calculation result and an overall variable efficiency simulation calculation result through numerical simulation calculation in numerical simulation software;

step four, calculating the grade performance parameters of each grade in a grading way:

and step-by-step decomposition is carried out on the overall performance parameters of the three-level axial flow compressor model stage obtained in the step two according to the variable efficiency proportionality coefficients of all levels and the energy head proportionality coefficients of all levels:

first-order energy head: h is_1pol＝λ₁h_polη first-stage variable efficiency_1pol＝μ₁η_pol；

Secondary energy head: h is_2pol＝λ₂h_polη second-stage variable efficiency_2pol＝μ₂η_pol；

Third-level energy head: h is_3pol＝λ₃h_polη three-stage variable efficiency_3pol＝μ₃η_pol。

Compared with the prior art, the invention has the following technical effects:

the method (I) obtains relatively accurate single-stage performance parameters of the axial flow compressor model stage capable of guiding industrial application through multi-stage overall tests and combination of decomposition calculation and numerical simulation of each stage.

The method is applied to the model-level test of the axial flow compressor, effectively promotes the model-level test process of the axial flow compressor, improves the research level of basic tests, and provides powerful support for the development of new blade profiles of the axial flow compressor and the upgrading and upgrading of products and the technical progress.

The present invention will be explained in further detail with reference to examples.

Detailed Description

In the present invention, the low pressure ratio means that the single stage compression ratio in the axial compressor model stage is lower than 1.15.

In the present invention, the energy head means power.

In the invention, the numerical simulation software is the known CFD numerical simulation software commonly used in the field of axial flow compressor model grade.

The invention provides a general thinking method for obtaining relatively accurate axial flow compressor model-level single-stage performance parameters by organically combining a multi-level model overall test performance characteristic parameter, a numerical simulation performance characteristic parameter, an energy head and efficiency decomposition.

The invention designs a three-stage axial flow compressor model stage. Arranging a total pressure probe, a static pressure probe and a total temperature probe in the inlet flow passage, arranging a static pressure measuring hole to be connected with the transmitter and transmitting signals to the acquisition system, and measuring and acquiring the average total pressure, the total temperature and the static pressure in the inlet flow passage. Arranging a total pressure probe and a total temperature probe in the outlet flow channel, arranging a static pressure measuring hole to be connected with the transmitter and transmitting signals to the acquisition system, and measuring the average total pressure, the total temperature and the static pressure in the outlet flow channel. And arranging a total pressure probe on the section of the interstage, connecting the total pressure probe with a pressure transmitter, transmitting a signal to a collecting system, and measuring the total pressure of a single point in the interstage flow channel.

The total pressure probe, the static pressure probe and the total temperature probe in the inlet flow channel are arranged at a position, away from an inlet guide vane, of the inlet flow guide part (a manually lengthened flow channel during the model level design of the axial flow compressor), where airflow is stable, and the distance between the airflow and the inlet guide vane is more than three times of the chord length. The total pressure, static pressure and total temperature probes are arranged in an equal ring area distribution mode, and the measured data can represent average parameters of the section.

The total pressure probe, the static pressure probe and the total temperature probe in the outlet flow channel are arranged in a position, in the outlet flow channel (an artificially lengthened flow channel during model level design of the axial flow compressor), of which the distance from the outlet rear guide vane is more than six times of the chord length and the airflow is stable. The total pressure, static pressure and total temperature probes are arranged in an equal ring area distribution mode, the influence of air flow convoluted flow factors is considered, the corresponding angle of the probe installation is properly adjusted, and the average parameter of the section which can be represented by measured data is calculated.

The overall performance of the model level of the three-level axial flow compressor can be calculated according to the total pressure, the total temperature and the static pressure tested in the inlet and outlet flow passages, and the overall pressure rise and the temperature rise of the three levels are far larger than those of a single level. For example, when the temperature rise of the axial flow compressor is 15-45 ℃, the total error of the conventional temperature measurement transmitter is 0.5 ℃, the error of temperature measurement is small, and if the power or efficiency of the axial flow compressor is calculated according to the temperature rise, the error is less than 2%. The method meets the requirements of relevant test standards, and relatively accurate thermal performance parameters meeting the standard requirements can be completely obtained by utilizing the calculation of a thermal equilibrium method.

And adjusting and measuring performance parameters of different working condition points through an outlet adjusting valve to draw a three-level performance curve.

Comparing theoretical calculation and test results, comparing total pressure values of interstage single-point tests in the test with total pressure values of corresponding points in the numerical simulation calculation results, adjusting a numerical simulation calculation model, a grid and the like to enable the test results and the numerical simulation results to be consistent, decomposing three-stage total performance of the test according to the power distribution proportion of the numerical simulation results, and calculating corresponding thermal parameters through power decomposition to obtain single-stage performance parameters.

In order to obtain the performance parameters of a specific certain single stage, the test rotating speed can be adjusted at different working condition points according to the test requirements, so that the test of the stage is carried out under the specific Mach number.

The invention measures the total inlet pressure (P) according to the working condition point_1st) Static inlet pressure (P)_1s) Effective temperature of inlet (T)_1p) Total outlet pressure (P)_2st) Static outlet pressure (P)_2s) Effective temperature at the outlet (T)_2p) Mass flow (Q) measured on a test line_m) And the coefficient of restitution (gamma) of the total temperature probe obtained by the early test, the related geometric dimension parameter and the medium characteristic parameter of the model level of the axial flow compressor can calculate the related thermal characteristic parameter of the model level of the three-level axial flow compressor.

The following embodiments of the present invention are provided, and it should be noted that the present invention is not limited to the following embodiments, and all equivalent changes based on the technical solutions of the present invention are within the protection scope of the present invention.