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.

Study of the Discharge Pressure Pulsation Within Twin Screw Compressors

2001 ◽  
Author(s):  
Ziwen Xing ◽  
Xueyuan Peng ◽  
Xiaojun Zhang ◽  
Tiansheng Cui
Keyword(s):  
Gas Flow ◽  
Pressure Pulsation ◽  
Theoretic Analysis ◽  
One Dimensional ◽  
Flow Equations ◽  
Twin Screw ◽  
Flow Through ◽  
The One ◽  
Discharge Pressure ◽  
Unsteady Gas Flow

Abstract Even in the absence of valves, flow through the discharge port of a screw compressor is oscillatory in nature. This unsteady but periodic flow variation at the discharge port excites the pressure pulsation. In this paper, the one-dimensional unsteady gas flow equations describing the discharge pressure pulsation are established, which allow for the effects of the viscosity friction and heat transfer between the gas and the pipe, and the boundary conditions of discharge pressure pulsation are considered. With Two-Step Lax-Wendroff scheme used, the one-dimensional unsteady gas flow equations are solved. In order to verify the theoretic analysis, the discharge pressure pulsation at variable working conditions is measured. It is shown that the model established in this paper is valid for getting a better understanding of the mechanism governing the behavior of the pressure pulsation in discharge pipe. It is found that the most important factor that affects the discharge pressure pulsation is the pressure difference between the actual discharge pressure and the design discharge pressure.

Paper 2: Effects of Reciprocating Compressor Valve Design on Performance and Reliability

1969 ◽  
Vol 184 (18) ◽  
pp. 9-23
Author(s):  
H. Davis
Keyword(s):  
Effective Area ◽  
Reciprocating Compressor ◽  
Valve Design ◽  
Pressure Losses ◽  
Valve Motion ◽  
In Series ◽  
Equivalent Area ◽  
Flow Through ◽  
Compressor Performance ◽  
Motion Characteristics

The effect of flow through compressor valve restrictions on the efficiency of the cylinder is well known. This paper provides a method of predetermining these pressure losses from the geometry of the valve design and the application conditions of the compressor stage. The model analysed is that of flow through multiple restrictions in series. The end result is a derived quantity, the ‘equivalent area’, which is the effective area of a single restriction equivalent to the total effect of the actual multiple restrictions. The relationships involving the effects of equivalent area and all other compressor parameters on compressor performance is presented in non-dimensional form. Tests are described which determined actual values of equivalent area for several valve designs and the correlations are presented, which confirm the ability to predict performance of an untested valve from its design and application. Reliability criteria are hypothesized based on considerations of the motion characteristics of the valve elements. Experimental observations of valve motion are described, and the desired characteristics defined from which the quantitative criteria are obtained. Correlations between criteria limits and field experience are presented.

Experiences in Developing a Practical Algorithm of Identification and Attenuation of Pressure Pulsation and Piping Vibration in Gas Reciprocating Compressor Plants and Other Systems

2018 ◽  
Author(s):  
Maciej Rydlewicz ◽  
Wojciech Rydlewicz
Keyword(s):  
Pressure Pulsation ◽  
Industrial Applications ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Mechanical Vibrations ◽  
Dynamic Forces ◽  
Piping Systems ◽  
Practical Engineering ◽  
Gaseous Media ◽  
Practical Algorithm

This paper presents results of research on practical engineering solutions to suppress pressure pulsation and mechanical vibrations in piping systems. It concerns both new build and retrofitted plants. Analyses were performed according to ASME B31, EN-13480 and API 618 codes. Solutions were considered for natural gas reciprocating compressor stations (gaseous media) and liquid hydrocarbons plant with various pumps. Pressure pulsation in a piping system is a source of dynamic forces. Unbalanced pressure layout in the piping system results in the presence of dynamic forces that may excite mechanical vibrations [1,7, 22, 23, 24]. In industrial applications, mechanical vibrations are present mostly in resonant conditions. Since hundreds of eigenvalues can characterise the piping system, it is crucial to identify the key ones, which are likely to be excited to vibrate. Therefore, it is necessary to allow adequate modelling and subsequent analysis of the fluid-structure interaction with available engineering tools.

Paper 3: Steady Flow Tests on Twin Poppet Valves

1967 ◽  
Vol 182 (4) ◽  
pp. 126-133 ◽  
Author(s):  
W. A. Woods
Keyword(s):  
Steady Flow ◽  
Pressure Loss ◽  
Pressure Ratio ◽  
Effective Area ◽  
Valve Lift ◽  
Cylinder Wall ◽  
Large Area ◽  
Pressure Losses ◽  
Flow Through ◽  
Poppet Valves

This paper presents the results of an experimental investigation of steady flow through a pair of exhaust poppet valves. An account is given of the gas exchange process on engines which use poppet valves and the reason why pressure losses should be kept to a minimum is explained. Tests carried out on the cylinder head of a uniflow two-stroke cycle engine are described following a brief description of the apparatus used. The results of a simple analysis of incompressible flow are also given. It is shown that the two previous models of flow through a valve, namely the sudden enlargement and constant static pressure, both give unrealistic pressure losses for large area ratios, i.e. at high valve lifts. A new model is introduced which leads to realistic pressure losses at small and large area ratios, i.e. at low and high valve lifts. Effective areas for the present tests are calculated on the basis of the constant pressure model, and details of calculation of pressure losses are outlined. The blockage effect caused by placing the exhaust valves near the cylinder wall is given in the discussion of the test results. This is zero for 0 < l/d < 0·08, but reaches a maximum blockage of 10 per cent at l/d = 0·28. With unrestricted twin valves the effective area is about twice that of a single valve up to l/d = 0·18 with a progressively larger effective area at lifts up to 13 per cent higher at l/d = 0·4. A comparison is also made with other data readily available. The pressure losses determined from the tests were analysed using a parameter derived in the simple theory. The parameter used is found to be almost independent of pressure ratio and the results are presented by means of this pressure loss parameter as a function of valve lift. The representation provides a quantitative method of comparing the performance of a given configuration of valve and port. On this basis the twin poppet valves are shown to give a slightly higher pressure loss than a single valve.

Analysis of Pressure Pulsations in Reciprocating Compressor Piping Systems

1966 ◽  
Vol 88 (2) ◽  
pp. 164-168 ◽  
Author(s):  
S. S. Grover
Keyword(s):  
Field Test ◽  
Test Data ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Practical Application ◽  
Pressure Pulsations ◽  
System A ◽  
Piping Systems ◽  
Limiting Condition

This paper deals with pulsations in pressure and flow in the reciprocating compressor and connected piping system. A model is presented that describes the excitation at the compressor and the propagation of the pulsations in the interconnected piping. It has been adapted to digital computations to predict the pulse magnitudes in reciprocating compressor piping systems and to assess measures for their control. Predicted results have been compared with field test data and with simplified limiting condition results. A discussion of its practical application is included.

Vibration Experiments and Numerical Simulations of Pulsation Behavior in Actual Size Mock-Up Piping

2010 ◽  
Author(s):  
Akira Maekawa ◽  
Tsuneo Takahashi ◽  
Takashi Tsuji ◽  
Michiyasu Noda ◽  
Minoru Kato ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Nuclear Power ◽  
Pressure Pulsation ◽  
Acoustic Resonance ◽  
Plunger Pump ◽  
Resonance Behavior ◽  
Inner Pressure ◽  
Opening Ratio ◽  
Valve Opening ◽  
Actual Size

Vibration experiments for pressure pulsation behavior were made using actual size mock-up piping of nuclear power facilities. The mock-up was a closed loop consisting of a three-strand plunger pump, tanks, piping and valves. It was 40 m long to allow interaction of the acoustic resonance frequency of fluid inside with the mechanical natural frequency of the piping. The influence of valve closing and opening operations to change inner pressure during pump operations on the pulsation boundary condition was investigated in this study. A drastic change in the boundary condition of the acoustic resonance behavior by using a slightly different valve opening ratio to set a different inner pressure was shown in the experimental results. The phenomenon was numerically simulated by using the method of characteristics. The simulation results showed that the boundary condition of the acoustic resonance changed from the closing-opening condition to the closing-closing condition when the valve opening ratio was changed slightly from 10% to 15%. This indicated that the boundary condition of the acoustic resonance had a pulsed change. Therefore, the boundary condition of the acoustic resonance was sensitive to a slight change of the valve opening ratio.

Heat Flux Sensor With Minimal Impact on Boundary Conditions

2003 ◽  
Author(s):  
Arash Saidi ◽  
Jungho Kim
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Flux ◽  
Heat Flux Sensor ◽  
Inverse Heat Conduction ◽  
Minimal Impact ◽  
Sensor Performance ◽  
Flow Through ◽  
Flux Sensor ◽  
The Ideal

A technique for determining the heat transfer on the far surface of a wall based on measuring the heat transfer and temperature on the near wall is presented. Although heat transfer measurements have previously been used to augment temperature measurements in inverse heat conduction methods, the sensors used alter the heat flow through the surface, disturbing the very quantity that is desired to be measured. The ideal sensor would not alter the boundary condition that would exist were the sensor not present. The innovation of this technique in that it has minimal impact on the wall boundary condition. Since the sensor is placed on the surface of the wall, no alteration of the wall is needed. The theoretical basis for the experimental technique as well as experimental results showing the heat flux sensor performance is presented.

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