CN-122021008-A - Full-working-condition performance prediction and interstage cooling matching method for high-speed electric drive air compressor

CN122021008ACN 122021008 ACN122021008 ACN 122021008ACN-122021008-A

Abstract

The invention provides a full-working-condition performance prediction and interstage cooling matching method for a high-speed electric-driven air compressor, and relates to the technical field of air compressor performance optimization. According to the invention, through collecting corresponding parameters of the driving motor under two different conditions of water cooling or not at low rotation speed, the performance change of the compressor caused by cooling can be known, and the real performance of the compressor under the high rotation speed water cooling-free working condition is predicted, so that the real full-working condition performance map of the air compressor under the water cooling-free working condition is constructed, the real performance of the air compressor is more accurately known, the problem of misalignment of the performance map of the compressor under forced heat transfer of motor cooling liquid and a compression working medium is avoided, and the high-efficiency operation of each stage of compressor is ensured, the efficiency of the multistage compressor is improved, and the optimization work of the design selection of the heat exchanger is realized based on the constructed full-working condition performance map prediction model.

Inventors

QI MINGXU
Wei Jiuxuan
ZHANG XU
ZHANG HONG

Assignees

北京理工大学

Dates

Publication Date: 20260512
Application Date: 20260126

Claims (9)

1. The full-working-condition performance prediction method of the high-speed electric-driven air compressor is characterized by comprising the following steps of: Setting the rotating speed of a driving motor corresponding to the air compressor to be tested to a plurality of different medium and low rotating speeds, and respectively collecting the mass flow, the inlet and outlet temperature and the inlet and outlet pressure of the air compressor to be tested under the condition of each rotating speed under the condition of water cooling or water cooling of the corresponding driving motor; Calculating a reduced rotating speed and a temperature difference caused by cooling based on the parameters, and constructing a linearization equation by utilizing the temperature difference caused by cooling and the relation between the actually measured mass flow and the reduced rotating speed; setting a driving motor of the air compressor to be tested to operate at a plurality of different water-cooled high speeds, inputting corresponding actual measurement operation parameters of the air compressor at each high speed into a linearization equation in the second step, and predicting the accurate outlet temperature of the air compressor corresponding to the corresponding high speed under the condition of no water cooling by utilizing the reverse operation of the linearization equation; And step four, according to the actual measured inlet temperature of the air compressor running at a high rotating speed under the anhydrous cooling working condition and the accurate outlet temperature predicted in the step three, the aerodynamic efficiency of the air compressor under the full working condition running state can be calculated by combining the actual measured inlet and outlet temperature of the air compressor running at a medium and low rotating speed under the anhydrous cooling working condition, and the aerodynamic efficiency is used for drawing a real full working condition performance diagram of the air compressor to be measured.
2. The method for predicting the full-working-condition performance of a high-speed electrically-driven air compressor according to claim 1, wherein in the second step, each medium-low rotating speed is lower than 50% of the full-working-condition rotating speed.
3. The method for predicting the full-working-condition performance of the high-speed electric-driven air compressor according to claim 1, wherein in the second step and the third step, the temperature T w of the input cooling water is constant under the condition that the driving motor is water-cooled.
4. The method for predicting the full-service performance of a high-speed electrically driven air compressor according to claim 3, wherein in the second step, a linearization equation is constructed by using a temperature difference caused by cooling and a relation between an actually measured mass flow and a reduced rotation speed, and the method comprises the following steps: S11, setting a reference temperature and a reference pressure, respectively calculating a reduced flow and a reduced rotation speed of a corresponding driving motor under the two conditions of low rotation speed and water cooling or not, and carrying out data unification on the inlet and outlet temperature and the pressure of the air compressor to be tested by using a spline interpolation method within the range of the reduced flow; S12, based on the temperature and pressure data unified in the step S11, respectively calculating the pneumatic power of the driving motor under the condition of water cooling or not, and calculating the pneumatic power difference b under the two conditions; S12, calculating according to the performance of the input fluid, the inlet and outlet temperature and the pressure parameter of the air compressor to be detected to obtain a heat transfer coefficient h of the air compressor to be detected; s13, calculating a characteristic heat transfer area A of the air compressor to be tested; s14, calculating a model theoretical temperature difference according to the pneumatic power difference b, the heat transfer coefficient h and the characteristic heat transfer area A, and recording the model theoretical temperature difference as ; S15, calculating to obtain the actual temperature difference according to the outlet temperature T 2 of the air compressor to be tested under water cooling and the upstream temperature T w of the cold side of the corresponding driving motor ; S16, setting a parameter R defined as ; S17, linearizing the parameter R to obtain a linearization equation R =F (m, N), where m is the measured mass flow and N is the reduced rotational speed.
5. The method for predicting full-service performance of a high-speed electrically driven air compressor according to claim 4, wherein in step S11, the method for calculating the reduced flow and the reduced rotation speed is as follows: Reduced flow = actual flow x (inlet temperature/reference temperature) 1/2 x (reference pressure/inlet pressure); Reduced speed = actual speed/(inlet temperature/reference temperature) 1/2 .
6. The method for predicting the full-working-condition performance of a high-speed electrically-driven air compressor according to claim 4, wherein in S12, the pneumatic power of the driving motor under the condition of water cooling is calculated, and the process is as follows: Aerodynamic power = mass flow Constant pressure specific heat capacity (Outlet temperature-inlet temperature) The mass flow is actually measured, and the inlet and outlet temperatures are uniform.
7. The method for predicting full-service performance of a high-speed electrically-driven air compressor according to claim 4, wherein in S13, the characteristic heat transfer area is a projected area of the impeller and the diffuser of the air compressor along the axial direction.
8. The method for predicting the full-working-condition performance of a high-speed electrically-driven air compressor according to claim 1, wherein in the third step, each high rotating speed is higher than 50% of the full-working-condition rotating speed.
9. The interstage cooling matching method of the high-speed electric drive air compressor is characterized by comprising the following steps of: firstly, according to the full-working-condition performance prediction method of the high-speed electric drive air compressor, which is disclosed by any one of claims 1-8, after a full-working-condition performance diagram of the air compressor is drawn, determining a flow over-matching threshold value corresponding to a multi-stage air compressor system and a flow over-matching threshold value of each stage of air compressor according to the full-working-condition performance diagram; Setting the hot side outlet temperature of the interstage heat exchanger to a target cooling temperature, carrying out corresponding parameter folding on an all-working-condition performance chart of a lower-stage air compressor corresponding to the heat exchanger according to the target cooling temperature and the corresponding outlet pressure, and calculating the temperature and the pressure of an outlet working medium of the corresponding air compressor; Thirdly, according to the full working condition performance diagram and the temperature and pressure of the air compressor outlet working medium calculated in the second step, performing inverse operation by using a linearization equation in a prediction method to obtain the air compressor outlet temperature of the corresponding driving motor under the cooling condition, and calculating the mass flow of the cold side working medium of the corresponding heat exchanger; and fourthly, adjusting the cold side mass flow parameter of the heat exchanger in the mass flow range of the cold side working medium obtained through recalculation, so as to realize optimization of the working condition matching result of the multi-stage air compressor.

Description

Full-working-condition performance prediction and interstage cooling matching method for high-speed electric drive air compressor Technical Field The invention relates to the technical field of air compressor performance optimization, in particular to a full-working-condition performance prediction and interstage cooling matching method for a high-speed electric drive air compressor. Background In order to adapt to the new pattern of global energy development and achieve the aim of 'double carbon' strategy, the related technical research of the electric air compressor is an important research and development direction in energy power system equipment. The practical and effective real-machine verification work is a basis for guaranteeing structural optimization and working condition matching of the air compressor. The existing motor used for the electric air compressor is easy to overheat and damage especially at high rotation speed, so that the safe operation of the motor is generally ensured by adopting a water cooling mode. However, due to the water cooling process of the motor, the heat of the compressed air is transferred to the liquid water in a heat conduction and convection heat transfer mode, and the measured temperature of the compressed air in the situation is obviously lower, so that the pneumatic efficiency in the measured performance diagram of the electric compressor is finally over estimated. When the flow rate of the matched working condition is too high, the pneumatic efficiency is seriously deviated from a true value, so that accurate regulation and control cannot be realized and the working condition of the electric air compressor is matched and optimized. Disclosure of Invention In view of the above, the invention aims to provide a full-working condition performance prediction and interstage cooling matching method for a high-speed electric drive air compressor, which not only can ensure to effectively solve the problem of overestimation of the pneumatic efficiency of the air compressor, but also can optimize the working condition matching result based on the predicted full-working condition performance diagram, thereby improving the authenticity and effectiveness of the pneumatic test experimental result of the electric air compressor, improving the running efficiency of a motor and realizing the efficient utilization of electric power energy. In order to achieve the above purpose, the present invention adopts the following technical scheme: a full-working-condition performance prediction method of a high-speed electric drive air compressor comprises the following steps: Setting the rotating speed of a driving motor corresponding to the air compressor to be tested to a plurality of different medium and low rotating speeds, and respectively collecting the mass flow, the inlet and outlet temperature and the inlet and outlet pressure of the air compressor to be tested under the condition of each rotating speed under the condition of water cooling or water cooling of the corresponding driving motor; Calculating a reduced rotating speed and a temperature difference caused by cooling based on the parameters, and constructing a linearization equation by utilizing the temperature difference caused by cooling and the relation between the actually measured mass flow and the reduced rotating speed; setting a driving motor of the air compressor to be tested to operate at a plurality of different water-cooled high speeds, inputting corresponding actual measurement operation parameters of the air compressor at each high speed into a linearization equation in the second step, and predicting the accurate outlet temperature of the air compressor corresponding to the corresponding high speed under the condition of no water cooling by utilizing the reverse operation of the linearization equation; And step four, according to the actual measured inlet temperature of the air compressor running at a high rotating speed under the anhydrous cooling working condition and the accurate outlet temperature predicted in the step three, the aerodynamic efficiency of the air compressor under the full working condition running state can be calculated by combining the actual measured inlet and outlet temperature of the air compressor running at a medium and low rotating speed under the anhydrous cooling working condition, and the aerodynamic efficiency is used for drawing a real full working condition performance diagram of the air compressor to be measured. The invention has the beneficial effects that by collecting corresponding parameters of the driving motor under two different conditions of water cooling at low rotation speed, the performance change of the compressor caused by cooling can be known, the real performance of the compressor under the high rotation speed water cooling-free working condition can be predicted, and the problem of misalignment of the compressor performance diagram caused by direct measuremen