scholarly journals Modeling reciprocating compressor valve dynamics

2017 ◽  
Author(s):  
Volf Michal ◽  
Gášpár Roman
Keyword(s):  
Reciprocating Compressor ◽  
Valve Dynamics

Experiences With Simulation of Reciprocating Compressor Valve Dynamics

1996 ◽  
Author(s):  
Brian Howes ◽  
Leonard Lin ◽  
Val Zacharias
Keyword(s):  
Gas Flow ◽  
Economic Effect ◽  
Operating Conditions ◽  
Valve Lift ◽  
Reciprocating Compressor ◽  
Compression Process ◽  
Flow Area ◽  
Valve Dynamics ◽  
Compressor Performance ◽  
Cylinder Flow

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.

scholarly journals Influence of compressible medium on the operation of a reciprocating compressor

2018 ◽  
Vol 245 ◽  
pp. 04009
Author(s):  
Andrey Kotlov ◽  
Leonid Kuznetsov ◽  
Boris Hrustalev
Keyword(s):  
Piston Compressor ◽  
Compressible Medium ◽  
Reciprocating Compressor ◽  
Flow Area ◽  
Suction System ◽  
Piston Velocity ◽  
Number Of Factors ◽  
Valve Dynamics ◽  
Pressure Changes ◽  
Oscillatory Processes

A reciprocating compressor is a volumetric machine. Consequently, the motion of gas in communications always is of non-stationary or pulsating character. The diagram of oscillatory processes in communications is complex because a number of factors affect the nature of the flow: cyclical gas supply, valve dynamics, change in the flow area of pipelines, variable cylinder volume, variable piston velocity, temperature gradients, etc. The analysis of non-stationary processes in the suction stage of a household refrigeration compressor is considered. A mathematical model of the flow of real gas in the suction system of a household refrigeration piston compressor has been developed. We performed a calculation study of the motion diagram of the suction valve, gas velocities in the suction pipe and pressure changes in the suction chamber. The results of a reciprocating compressor study while compressing various gases are given. The influence of the properties of refrigerants on the operation of the compressor and the suction system is considered.

Development of a transient gas dynamic model for the simulation of pulsation in reciprocating compressor piping systems

2017 ◽  
Vol 232 (6) ◽  
pp. 685-695 ◽  
Author(s):  
Liu Zhan ◽  
Zhenya Duan
Keyword(s):  
Boundary Condition ◽  
Dynamic Model ◽  
Pressure Pulsation ◽  
Effective Area ◽  
Reciprocating Compressor ◽  
Flow Equations ◽  
Piping Systems ◽  
Nonlinear Transient ◽  
Valve Dynamics ◽  
Flow Through

The subject of this paper is to develop a nonlinear transient dynamic model for simulating the pressure pulsation in reciprocating compressor piping systems. The model allows the interaction between the piping response and compressor processes. The two-step Lax–Wendroff method is employed to obtain solutions to the unsteady flow equations at internal points in a pipe, and the Trapezoidal version of the method of characteristics is adopted for handling boundary conditions. The compressor, which serves as a boundary condition for predicting the piping's pressure pulsation, is modeled comprehensively on the basis of the first law of thermodynamics, the valve dynamics assumed as a one-degree-of-freedom system and the flow through valve by introducing an effective area for flow through the valve throat. It is worth to note that, to solve the compressor boundary condition, all the related equations are necessary to be solved simultaneously to obtain the pulsating pressure in the pipe end, pressure variation in the cylinder, valve response, mass flow rate, indicated power, and other compressor performance parameters. Numerical results based on these proposed modeling techniques show a good agreement with previous measured data.

The Theory of Spring-Loaded Valves for Reciprocating Compressors

1950 ◽  
Vol 17 (4) ◽  
pp. 415-420
Author(s):  
Michael Costagliola
Keyword(s):  
Natural Frequency ◽  
Reciprocating Compressor ◽  
Important Criterion ◽  
Flow Area ◽  
Main Design ◽  
Design Variables ◽  
Flow Test ◽  
Piston Speed ◽  
Valve Dynamics ◽  
Static Flow

Abstract The inlet and discharge processes of a reciprocating compressor equipped with spring-loaded valves of the automatic type have been analyzed to determine the effects of the main design variables on performance. The most important criterion is found to be a parameter involving effective flow area through the valves and piston speed. Valve dynamics is a secondary consideration. For optimum valve dynamics, the valve would have no weight and a very small spring constant, giving an infinite natural frequency of the valve system. If certain valve characteristics are known (or measured by static-flow test), the performance of a compressor using these valves can be predicted with fair accuracy.

Aortic valve dynamics after valve-sparing procedure with a new sinus prosthesis

2014 ◽  
Vol 62 (S 01) ◽  
Author(s):  
C. Schmidtke ◽  
D. Richardt ◽  
A. Karluss ◽  
H.-H. Sievers
Keyword(s):  
Aortic Valve ◽  
Valve Dynamics ◽  
Valve Sparing
Sign in / Sign up

Export Citation Format

Share Document