Reed Valve Dynamics of Reciprocating Compressor – A Review

Experience with compressor valve modelling has shown that reciprocating compressor performance can sometimes be improved by subtle changes in valve design. Modelling has led to a better understanding of the physical behaviour of valves and of the compression process. Three compressor valve studies presented here demonstrate the benefits of valve modelling. Case 1 challenges the commonly held assumption that reducing the lift of a compressor valve will reduce the efficiency of the compressor. The capacity of this compressor is increased by reducing the valve lift. A plot of BHP/MMSCFD versus valve lift shows an inflection point that assists the analyst in optimizing the design. Case 1 also presents a method of calculating the economic effect of improvements in valve performance. Case 2 demonstrates the effect of inadequate flow area through the valve. Pressure in the clearance volume cannot decrease fast enough if flow areas are inadequate; the result is late valve closure, and therefore decreased valve life. Case 3 shows the importance of considering the design of the cylinder casting in addition to that of the valves. Here, insufficient cylinder flow area constricted gas flow. Since these cases were simulated, the analyst had the opportunity to evaluate the proposed solution over the entire range of operating conditions. He was able to select a valve which solved the immediate problem and be confident that it would perform adequately throughout the specified range of conditions.

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Simulation and Experiment Study on Dynamic Characteristic of Reed Valve of Reciprocating Compressor Based on Fluid-Structure Interaction Model

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1180/1/012021 ◽

2021 ◽

Vol 1180 (1) ◽

pp. 012021

Author(s):

Yanbin Wang ◽

Bei Guo ◽

Kai Ma ◽

Yuhang Zhou

Keyword(s):

Dynamic Characteristic ◽

Fluid Structure Interaction ◽

Interaction Model ◽

Reciprocating Compressor ◽

Experiment Study ◽

Fluid Structure ◽

Structure Interaction ◽

Simulation And Experiment ◽

Reed Valve

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Reliability design of a reciprocating compressor suction reed valve in a common refrigerator subjected to repetitive pressure loads

Engineering Failure Analysis ◽

10.1016/j.engfailanal.2009.12.001 ◽

2010 ◽

Vol 17 (4) ◽

pp. 979-991 ◽

Cited By ~ 19

Author(s):

Seong-woo Woo ◽

Dennis L. O’Neal ◽

Michael Pecht

Keyword(s):

Reciprocating Compressor ◽

Reliability Design ◽

Reed Valve

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Effect of Oil on the Dynamics of Compressor Suction Valve

Volume 1C: 16th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc97/vib-4029 ◽

1997 ◽

Author(s):

H. Ezzat Khalifa ◽

Xin Liu

Keyword(s):

Relative Effect ◽

Viscous Force ◽

Reciprocating Compressor ◽

Cylinder Pressure ◽

Oil Viscosity ◽

Valve Seat ◽

Rapid Release ◽

Valve Stiction ◽

Valve Opening ◽

Reed Valve

Abstract The presence of oil on the suction valve of a reciprocating compressor has long been known to be responsible for the so-called valve stiction phenomenon. With stiction, the opening of the valve is delayed until later in the suction stroke, which results in a reduction in volumetric efficiency and increases the probability of valve failure. In this paper, a model is presented for analyzing the dynamic behavior of a round reed valve in the presence of oil. It is shown that the primary reason for stiction is the viscous force arising from dilating the oil film between the valve and its seat. This dilation takes place as the cylinder pressure on one side of the valve reed falls below the suction pressure in the intake plenum upstream of the valve. The viscous force delays the valve opening until later in the suction stroke. Because the film dilation resistance is directly proportional to the oil viscosity and decreases rapidly as the film thickens, the film eventually breaks and the valve begins to accelerate rapidly until it impacts the valve stop. The delayed rapid release of the valve and the associated impact are shown to subject the valve to much higher forces than would be experienced without the effect of stiction. The relative effect of oil viscosity and valve/seat contact area on valve force is presented for a representative reciprocating compressor equipped with suction valves.

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