CN-122014683-A - Centrifugal compressor feedforward cooling control method and system and centrifugal compressor

CN122014683ACN 122014683 ACN122014683 ACN 122014683ACN-122014683-A

Abstract

The invention discloses a centrifugal compressor feedforward cooling control method, a system and a centrifugal compressor, wherein the method can be used for carrying out advanced, accurate and self-adaptive adjustment on the flow of a cooling medium based on the characteristic of an airflow edge Cheng Wensheng in the running process of the centrifugal compressor, predicting the wall temperature change in the running process of the centrifugal compressor in advance through a dynamic feedforward mechanism, realizing advanced regulation and active temperature control, overcoming the defect of traditional feedback control of delayed regulation, eliminating model errors and disturbance by combining feedback correction, enabling the wall temperature of a diffuser and a volute to be stably controlled in a target range, improving control precision, effectively avoiding local overheat or supercooling, simultaneously carrying out cooling on the wall surfaces of the diffuser and the volute, controlling the wall surface temperature, reducing thermal stress and thermal fatigue damage of the wall surfaces of the diffuser and the volute, and prolonging the service life of equipment.

Inventors

Bai Gen
GAO XINYUE
DAI YONGGUANG
FANG JIAN

Assignees

南京磁谷科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260317

Claims (10)

1. A feedforward cooling control method of a centrifugal compressor is characterized by comprising the following steps: S01, establishing a gas temperature rise mechanism model and a shell wall thermal dynamic model according to a gas flow path of the centrifugal compressor, acquiring temperature change data of gas in each flow stage through the gas temperature rise mechanism model, and acquiring heat exchange data between the gas and the shell wall of the corresponding flow path through the shell wall thermal dynamic model; s02, predicting the temperature of the corresponding shell wall surface based on temperature change data and heat exchange data in the gas flowing process of the centrifugal compressor, and obtaining predicted wall surface temperature; S03, taking the predicted wall temperature as a reference of feedforward cooling control, calculating feedforward cooling control quantity, and cooling the shell wall.
2. The method for controlling feedforward cooling of a centrifugal compressor according to claim 1, wherein when the wall surface of the casing is cooled, the feedforward cooling control amount is feedback-corrected according to the deviation between the wall temperature of the casing and the target wall temperature acquired in real time, and the flow of the cooling medium required for cooling the wall surface of the final casing is determined.
3. The method for controlling feedforward cooling of a centrifugal compressor according to claim 2, wherein when a gas temperature rise mechanism model and a shell wall surface thermal dynamic model are established, a real-time operation condition of the centrifugal compressor is taken as input, a model is established in sections according to the change of the gas flow state by taking the airflow flow paths of an impeller outlet, a diffuser and a volute, and feedforward cooling control is independently performed in the section areas.
4. The method for controlling feedforward cooling of a centrifugal compressor according to claim 3, wherein the temperature rise mechanism model comprises an impeller outlet total temperature mechanism model, a diffuser pneumatic temperature rise mechanism model and a volute heat dissipation temperature rise mechanism model; The impeller outlet total temperature mechanism model is used for calculating the outlet total temperature of the airflow after the impeller does work, , wherein, The total inlet temperature of the compressor; Isentropic efficiency of the impeller; gas insulation index; impeller pressure ratio; The diffuser pneumatic temperature rise mechanism model is used for calculating the total temperature of the outlet airflow of the diffuser, , , wherein, Diffuser efficiency; diffuser inlet airflow velocity; Diffuser outlet airflow speed; the specific heat capacity of the gas is fixed; the volute heat dissipation and temperature rise mechanism model is used for calculating the temperature of airflow in the volute : , The loss coefficient of the volute.
5. A method of controlling feedforward cooling in a centrifugal compressor according to claim 3, wherein the prediction is based on a shell wall thermodynamic model The corresponding shell wall temperature after the time, , The wall surface is heated by the air flow, The heat dissipation capacity of the shell wall facing the cooling medium is obtained, wherein, Diffuser/volute wall temperature at the current time (time t); predicting time length; diffuser/volute wall heat capacity; the heat exchange coefficient of the air flow and the wall surface; The heat exchange area of the air flow and the wall surface; The temperature of main flow in the volute; the heat exchange coefficient of the wall surface and the cooling medium; The heat exchange area between the wall surface and the cooling medium and the inlet temperature of the cooling medium.
6. The method of claim 5, wherein the predicted wall temperature is based on a feed-forward cooling control of the centrifugal compressor Wall temperature with target Calculating the feedforward cooling control amount , wherein, Feedforward control of the proportionality coefficient; Feedforward control integral coefficient; diffuser/volute target wall temperature.
7. The method of claim 6, wherein the wall temperature is collected in real time Wall temperature with target Calculating the deviation of the feedback cooling correction amount , Feedback control of the proportionality coefficient; Feedback control integral coefficients; real-time actual measurement of wall temperature; Total control of delivered cooling capacity 。
8. A centrifugal compressor feedforward cooling control system, using the method of any one of claims 1-7, comprising a cooling module for providing cooling medium to the centrifugal compressor according to cooling demand, a temperature sensing module for detecting temperature data of the centrifugal compressor, and a control module for controlling flow of cooling medium according to the operating conditions of the centrifugal compressor, the control module pre-calculating feedforward cooling control amount required for the operation cooling of the centrifugal compressor according to the operating conditions of the centrifugal compressor, and performing cooling operation by the cooling module.
9. The centrifugal compressor feedforward cooling control system according to claim 8, wherein after the feedforward cooling control amount is calculated, a feedback cooling modifier is calculated based on a difference between a current centrifugal compressor casing wall temperature and a corresponding target temperature, and the total control transmission cooling amount is calculated as a final cooling medium flow rate by superposition of the feedforward cooling control amount and the feedback cooling modifier.
10. The centrifugal compressor is characterized by comprising a diffuser (1) and a volute body (2) which are integrally formed, wherein an air inlet end of the diffuser (1) is connected with a compressed gas outlet of the compressor, a first cooling flow passage (3) is uniformly formed in the wall surface of the diffuser (1), a second cooling flow passage (4) in annular design is formed in the inner wall of the volute body (2), the first cooling flow passage (3) and the second cooling flow passage (4) are communicated with a cooling module to form a closed loop cooling circuit, and temperature sensors for detecting the wall surface temperature in real time are arranged on the inner walls of the diffuser (1) and the volute body (2).

Description

Centrifugal compressor feedforward cooling control method and system and centrifugal compressor Technical Field The invention relates to the technical field of gas cooling of centrifugal compressors, in particular to a feedforward cooling control method and system of a centrifugal compressor and the centrifugal compressor. Background Under the high-pressure ratio multistage compression working condition, gas enters the diffuser and the volute to finish diffusion and flow collection after being compressed by the impeller, in the process, the internal energy of the gas rises and the temperature rises obviously, the compression work of a subsequent compression stage can be increased, the isothermal compression efficiency of the whole machine is reduced, the thermal deformation of components can be caused due to the rise of the temperature of the wall surface of the flow channel, and the matching property and the pressure stability of the flow field are affected. In addition, for a high-power magnetic suspension compressor, because the length of a rotor is large, the rotor is heated and the elongation is increased, so that the axial bearing clearance is changed greatly, the control is difficult, and the situation is aggravated by the transmission of pneumatic heat to the rotor. Meanwhile, the existing cooling control mode mostly adopts passive cooling, constant flow cooling or simple feedback control based on measured temperature, and the cooling logic of the cooling control mode depends on the temperature control of a conventional sensor, so that obvious defects are that on one hand, the simple feedback control belongs to hysteresis control of 'readjustment after temperature exceeding' and cannot deal with dynamic change of airflow along-path temperature rise in advance, local overheating or supercooling is easy to occur, and on the other hand, the existing control does not combine the along-path temperature rise characteristic of gas from an impeller outlet to a volute through a diffuser, and adopts a unified cooling strategy, so that the cooling precision is low, the energy consumption is high, and the temperature rise fluctuation under variable working conditions (change of rotating speed, flow and pressure ratio) of a compressor cannot be adapted. Disclosure of Invention The invention discloses a feedforward cooling control method and system for a centrifugal compressor and the centrifugal compressor, aiming at the defect of the existing centrifugal compressor in cooling gas. The technical scheme is that in order to achieve the technical purpose, the invention adopts the following technical scheme: A feedforward cooling control method of a centrifugal compressor comprises the following steps: S01, establishing a gas temperature rise mechanism model and a shell wall thermal dynamic model according to a gas flow path of the centrifugal compressor, acquiring temperature change data of gas in each flow stage through the gas temperature rise mechanism model, and acquiring heat exchange data between the gas and the shell wall of the corresponding flow path through the shell wall thermal dynamic model; s02, predicting the temperature of the corresponding shell wall surface based on temperature change data and heat exchange data in the gas flowing process of the centrifugal compressor, and obtaining predicted wall surface temperature; S03, taking the predicted wall temperature as a reference of feedforward cooling control, calculating feedforward cooling control quantity, and cooling the shell wall. Preferably, when the shell wall surface is cooled, the feedforward cooling control quantity is subjected to feedback correction according to the deviation between the shell wall temperature acquired in real time and the target wall temperature, and the cooling medium flow required by the final shell wall surface cooling is determined. Preferably, when the gas temperature rise mechanism model and the shell wall surface thermal dynamic model are built, the real-time operation working condition of the centrifugal compressor is taken as input, the airflow flow paths of the impeller outlet, the diffuser and the volute are taken as input, the model is built in sections according to the change of the airflow state, and feedforward cooling control is independently carried out in the section area. Preferably, the temperature rise mechanism model comprises an impeller outlet total temperature mechanism model, a diffuser pneumatic temperature rise mechanism model and a volute heat dissipation temperature rise mechanism model; The impeller outlet total temperature mechanism model is used for calculating the outlet total temperature of the airflow after the impeller does work, , wherein,The total inlet temperature of the compressor; Isentropic efficiency of the impeller; gas insulation index; impeller pressure ratio; The diffuser pneumatic temperature rise mechanism model is used for calculating the total temperature of the outle