Study On The Influence Of Filling Amount On Combustible Risk Of Rotor Compressor In R32 Recovery Process

With the improvement of people's awareness of environmental protection,new and higher requirements have been put forward in the refrigeration industry.Among them,low ODP and low GWP refrigerant are still the future research direction.The ODP of R32 refrigerant is 0,GWP is 675,and its thermal performance is very good,so it is a suitable alternative refrigerant.However,due to the micro-flammability of R32,its application is restricted.Especially in the process of refrigerant recovery,air intrusion into R32 air conditioning system will pose a great challenge to security,so it is very important to study the safety of air intrusion R32 air conditioning systemThis paper adopts theoretical analysis,experimental research and numerical simulation,the method of combining the R32 recycling process in this paper different refrigerant filling air intrusion and lubricating oil injection burnable risk inside the compressor rotor.The dynamic effects of different refrigerant filling amount and lubricating oil injection amount on the exhaust pressure of rotor compressor during air intrusion in R32 recovery process were studied experimentally.Experimental results show that:(1)The variation trend of compressor exhaust pressure with a refrigerant filling amount of 128 g is different from that of compressor exhaust pressure with a refrigerant filling amount of 384 g and 640 g when the air intrusion amount of R32 is constant.When the air intrusion is 10% of the inhalation volume,the maximum exhaust pressure of the refrigerant injection volume is 128 g,and its safety is the worst.When the air intrusion is 40% and 60% of the inhalation volume,the exhaust pressure of the refrigerant injection volume of 384 g after air intrusion is the highest,so its safety is the worst.(2)When there is a certain amount of air intrusion in R32 recovery process,the pressure of compressor exhaust and its rising speed increase with the increase of refrigerant filling amount.(3)When air intrusion is constant in R32 recovery process,the change trend of exhaust pressure of rolling rotor compressor is roughly the same,which is independent of the amount of lubricating oil injection.However,the exhaust pressure and rising rate of rotor compressor increase with the increase of lubricating oil.Because there is little difference in compressor exhaust pressure under different lubricating oil injection volume,the oil injection volume has little influence on compressor safety.Based on the experimental research,the effect of different refrigerant filling amount on the flammability risk of rotor compressor during air invasion in R32 recovery process was simulated.Research shows:(4)R32 recovery process for compressor suction volume of air into 40%,the amount of scroll compressor rotor under different filled volume of the refrigerant inside each measuring point by the potential damage(29.3%-100%)into the danger zone(14.4%-29.3%)and then enter the safe zone(0-14.4%).There is a large area of combustible area around the motor in the compressor,so the motor has combustible risk.(5)R32 and recycling process of air quantity for the compressor suction quantity 40%,the refrigerant filling quantity 128 g of combustible regional trends over time and the refrigerant filling quantity is 384 g,640 g of different combustible area over time.Under different refrigerant filling amount,the change of FVT(combustible volume time)can be roughly divided into two stages: slow increase stage and fast increase stage.With the increase of refrigerant charge,the later the starting time of the rapid increase phase is.Within 0s-105 s,the maximum amount of 128 g of refrigerant filling amount is FVT,and its combustible risk is the greatest.In 1055-120 s,the largest amount of FVT with the refrigerant filling amount of 384 g is the refrigerant,and its combustible risk is the biggest.During the whole refrigerant recovery process,the combustible risk is relatively small when the refrigerant is filled with 640 g.(6)When the air intrusion in R32 recovery process is 40% of the compressor's inspiratory volume,the internal temperature of the compressor decreases with the increase of refrigerant injection volume.With the same filling amount,the internal temperature of the compressor increases gradually from the rolling rotor outlet to the compressor outlet.For near the temperature inside the compressor motor,and the refrigerant filling quantity compared with 384 g,128 g filled volume of the refrigerant 640 g,inside the compressor motor near the lowest temperature of 126.2 ?,exceeded the insulator on the motor of the critical temperature,so the motor around flammable risk exists.For compressor oil temperature near the pool,and the refrigerant filling quantity compared to 128 g and 384 g,128 g amount of refrigerant filling in the compressor oil pool near the highest temperature of 130.8 ?,but not more than PVE oil ignition point,so air compressor oil is a relatively safe near the pool.This paper through the theoretical analysis,experiment research and numerical simulation of the combination of research methods to analyze the R32 recycling air intrusion different refrigerants in the process of filling quantity and oil injection burnable risk within the rotor compressor,the influence of the compressor burnable risk,for safety standards in the process of R32 rotor compressor recycling provides the technical basis is established.