The Reserch Of PV Diagram Testing System For Reciprocating Rerigerating Compressor

The PV diagram of reciprocating refrigerating compressor is an important tool of studying on online operation performance and status of reciprocating refrigerating compressor. Collecting the gas pressure signals in cylinder accurately and doing statistical or thermodynamic analysis, are the important foundations of product design and optimized improvement of refrigerating compressor.This paper researched multi-channel analogue test system that can collected pressure fluctuation from suction valve chamber, exhaust valve chamber and compression chamber in cylinder of reciprocating refrigerating compressor. It has an important significance for researching and evaluating the working process of refrigerant compressor and improving refrigeration performance of compressor. The main research contents and achievements of this thesis are as follows:First, this paper researched the actual working cycle of reciprocating refrigerating compressor, and compared the actual working cycle with the theoretical, and then proposed a pressure fluctuation phenomenon in cylinder in the suction and discharge process of compressor.Second, the paper expounded the reason of pressure fluctuation, described the part and dynamic characteristics of reed valve, analyzed the flow and working of reed valve in the working of compressor and its differential equation, thus determined the phenomenon that valve has a significant impact on pressure fluctuation.Third, according to the research contents about pressure fluctuation and dynamic characteristics of valve plate, this paper proposed a experimental scheme about PV diagram test system in cylinder of refrigerating compressor, and then determined the hardware part of data acquisition system, included data acquisition tool and sensors etc..Fourth, this paper designed the software part of the data acquisition system, realized the high-speed DMA mode data acquisition of the pressure and position signal, and then made the data preservation and data processing.Finally, the feasibility of the testing scheme has been verified through the building of the PV diagram test platform of the open refrigeration compressor; and the reliable experimental results has been obtained according to filtering and denoising the collected pressure signal from using the way of wavelet analysis technique.