Numerical model and investigations of reed valve motion characteristics of reciprocating compressor
Abstract
Reed valve is a key component of reciprocating compressors affecting the efficiency and reliability of the refrigeration system. In order to further investigate the influence of structural parameters on reed valve motion characteristics, theoretical and experimental analysis of a discharge valve dynamic behavior are carried out in this paper. Firstly, the dynamic models of discharge valve and suction valve based on energy conservation are established. Valve displacement, velocity and other transient motion characteristics can be analyzed by using the new model. Secondly, in order to verify the validity of the new model, the displacement testing system of a discharge valve is established. The experimental results show that the measured displacement curve is well agreement with the calculation curve. It means that the new model can be used to analyze the motion law and dynamic characteristics of the valve effectively. Thirdly, the effects of valve lift, stiffness coefficient and effective flow area on delayed closing angle, fully open period and maximum impact speed are investigated. The results show that when the valve lift is increased from 1.5 mm to 4mm, the closing angle is decreased from 362 degrees to 349 degrees. When the lift is 3mm-3.7mm, the maximum impact speed of the valve increased slowly, and closed timely. So the reasonable valve lift range is 3mm - 3.7mm. In addition, valve’s thickness has a direct effect on its stiffness coefficients. Valve plate flutter occurs when stiffness coefficients is more than 5000N/m, so the valve thickness cannot be designed more than 0.64mm accordingly. Moreover, with the reduction of effective flow area, the valve gradually closed delay. The effective flow area is not only affected by the diameter of valve port, but also the lift, the form of valve plate, cylinder diameter and other factors. Therefore, it is necessary to comprehensively consider these factors to increase the effective flow area. The researching on the motion law of reed valve can provide the theoretical basis for the rational optimization of valve structure.References
Bo Huang. 2008. Dynamic Analysis of the Discharge Valve of the Rotary Compressor. International Compressor Engineering Conference. Purdue University. article 1182.
Costagliola, M. & Great Neck, N. Y. 1950. The Theory of Spring-Loaded Valves for Reciprocating Compressors. Journal of applied mechanics 17(4): 415-420.
Daniel NAGY. 2008. Valve Lift Measurement for the Validation of a Compressor Simulation Model. International Compressor Engineering Conference. Purdue University. article 1274.
Hong, W., Jin, J. & Wu, R. 2009. Theoretical analysis and realization of stepless capacity regulation for reciprocating compressors. Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 223(4): 205-213.
Junghyoun Kim. 2006. Valve Dynamic Analysis of a Hermetic Reciprocating Compressor. International Compressor Engineering Conference. Purdue University. article C107.
Lawson S., Mclaren R.J.L. 1984. Approach to Computer Modeling of Reciprocating Compressors. Proceedings of the Purdue Compressor Technology Conference. Purdue University pp. 139-147.
Lin Mei, YaoJun, Pan shulin. 1997. Establishment of three mathematical models and comparison for the reed valves. Chinese Journal of Applied Mechanics 14(1):118-123.
Machu, E. 2001. Valve dynamics of reciprocating compressor valves with more than one degree of freedom. Proceedings of the ImechE. pp:1385-1392.
Shuhei NAGATA. 2010. Analysis of Dynamic Behavior of Suction Valve Using Strain Gauge in Reciprocating Compressor. International Compressor Engineering Conference at Purdue University. article 1273.
Wang, Feng, Chong Su, Guangyu Mu, andXiaozhen Mi. 2015. An axiomatic design optimization for suction reed valve component of compressors. IEEE 19thInternational Conference on Computer Supported Cooperative Work in Design. pp.368 – 371.
Wang Feng, Shang Haotian, Mi Xiaozhen, Tan Liang. 2016. Study on the Flow Characteristic of Discharge Reed Valve Based on CFD. China Journal of Refrigeration 37 (2):38-45.
Wang Y, Xue C, Feng J. 2013. Experimental investigation on valve impact velocity and inclining motion of a reciprocating compressor. Applied Thermal Engineering 61( 2):149-156.
Wambsganss, M. W. 1966. Mathematical Modeling and Design Evaluation of High-Speed Reciprocating Compressors. PHD Thesis, Purdue University.
Wu danqing,Cong jingtong. 1993. Mathematical simulation and design of compressor reed valve. Mechanical Industry Press. Beijing.
Yuan Ma, Zhilong He, Xueyuan Peng, Ziwen Xing. 2012. Experimental investigation of the discharge valve dynamics in a reciprocating compressor for trans-critical CO2 refrigeration cycle, Applied Thermal Engineering 32: 13-21.
