Attenuation of Gas Pulsation in the Valve Chamber of a Reciprocating Compressor Using the Helmholtz Resonator

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Xiaohan Jia ◽  
Boxiang Liu ◽  
Jianmei Feng ◽  
Xueyuan Peng
Keyword(s):  
Characteristic Frequency ◽  
Control Method ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Helmholtz Resonator ◽  
Resonance Region ◽  
Piping System ◽  
Reciprocating Compressor ◽  
The Finite Element Method ◽  
Attenuation Characteristics

This paper presents testing and analysis results associated with a new control method based on the Helmholtz resonator to suppress the pressure pulsations in the valve chamber and cylinder nozzle of a reciprocating compressor. The characteristic response of the designed Helmholtz resonator was analyzed and its attenuation characteristics on the gas pulsation were investigated. A three-dimensional acoustic model of the gas pulsation was established by means of the finite element method (FEM) for a compressor discharge piping system with and without the resonator. The gas column natural frequencies of the piping system and the pressure wave profiles were predicted using the presented model and validated by comparing the simulated results with the experimental data. The results showed that the pressure pulsating amplitude in the valve chamber was reduced by 40.4% when the resonator was installed. If the resonance frequency of the resonator shifted from the cylinder nozzle characteristic frequency by a range of ±13%, the reduction in the pressure fluctuations within the valve chamber was about 24%. The best attenuation effectiveness on the valve chamber, a reduction of 47%, was obtained when two resonators were installed on the valve covers of both the head and crank ends. Two new frequencies of 40.4 Hz and 66.9 Hz appeared to replace the original cylinder nozzle characteristic frequency of 53.9 Hz with the Helmholtz resonator installation, and the corresponding resonance region was transferred from the valve chamber to the resonator.

Attenuation of Gas Pulsation in a Reciprocating Compressor Piping System by Using a Volume-Choke-Volume Filter

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Boxiang Liu ◽  
Jianmei Feng ◽  
Zhongzhen Wang ◽  
Xueyuan Peng
Keyword(s):  
Characteristic Frequency ◽  
Pressure Pulsation ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Response Characteristics ◽  
Low Pass

This paper presents an investigation of the use of a volume-choke-volume low-pass filter to achieve gas pulsation attenuation in a reciprocating compressor piping system, with a focus on its frequency response characteristics and influence on the actual attenuation effects. A three-dimensional acoustic model of the gas pulsation was established for a compressor discharge piping system with and without the volume-choke-volume filter, based on which the gas column natural frequencies of the piping system and the pressure wave profiles were predicted by means of the finite element method. The model was validated by comparing the predicted results with the experimental data. The results showed that the characteristic frequency of the filter was sensitive to both diameter and length of the choke but independent of the parameters of the piping beyond the filter. It is worth noting that the characteristic frequency of the filter constituted one order of the gas column natural frequencies of the piping system with the filter. The pressure pulsation levels in the piping system downstream of the filter could be significantly attenuated especially for the pulsation components at frequencies above the filter’s characteristic frequency. The measured peak-to-peak pressure pulsation at the outlet of the filter was approximately 61.7% lower than that of the surge bottle with the same volume.

Pulsation attenuation in a reciprocating compressor piping system using a volume-perforated pipe-volume suppressor

2017 ◽  
Vol 232 (17) ◽  
pp. 3074-3084
Author(s):  
Quyang Ma ◽  
Zhenhuan Wu ◽  
Mengjun Li ◽  
Guoan Yang
Keyword(s):  
Three Dimensional ◽  
Fixed Ratio ◽  
Wave Theory ◽  
Piping System ◽  
Pulsation Frequency ◽  
Reciprocating Compressor ◽  
Pressure Pulsations ◽  
Cross Sectional ◽  
Transient Simulations ◽  
Perforated Pipe

A volume-perforated pipe-volume suppressor is introduced to study its performance in attenuating pressure pulsations. On the basis of plane wave theory, the work developed a mathematical model to predict the distribution of pressure pulsations in a reciprocating compressor piping system with the proposed suppressor. The theoretical predictions were verified through experiments and three-dimensional fluid dynamics transient simulations, and good agreements were attained. Results proved that the pressure pulsations were attenuated significantly when the suppressor was used. In the frequency domain, the amplitude at the first pulsation frequency was decreased considerably. Both the perforation and cross-sectional areas of the perforated pipe could influence the attenuating capacity. Given a fixed ratio of perforation area to cross-sectional area, the best damping performance could be obtained by increasing the number of perforated holes and reducing the hole diameter. The geometric recommendations produced in this work are useful to control pulsations and vibrations under different functioning conditions.

Time-Varying Behavior of a Statically Indeterminate Shafting System in a Hydrodynamic Journal Bearing

1987 ◽  
Vol 109 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Z. H. Karni ◽  
M. G. Parsons ◽  
Z. P. Mourelatos
Keyword(s):  
Control Method ◽  
Optimization Technique ◽  
Three Dimensional ◽  
Integration Time ◽  
Time Varying ◽  
The Finite Element Method ◽  
Time Step ◽  
Hydrodynamic Analysis ◽  
Oil Film ◽  
Hourglass Control

A new direct iterative method for obtaining the time-varying behavior of a statically indeterminate shafting system within one of its hydrodynamic journal bearings is described. A modified Newmark’s method is used to step in time. At each integration time step an optimization technique iterates between the shafting system and the oil film analyses until an equilibrium is achieved. The three-dimensional shafting system structural analysis and the two-dimensional oil film hydrodynamic analysis utilize the finite element method. The “hourglass control” method is employed for the construction of the oil film fluidity matrix. A numerical example illustrates the method.

Influence of a tapered cylinder nozzle on pressure pulsations in a variable high-speed reciprocating compressor piping system

2015 ◽  
Vol 231 (3) ◽  
pp. 600-612 ◽  
Author(s):  
Zhan Liu ◽  
Zengli Wang ◽  
Quanke Feng ◽  
Xiaoling Yu
Keyword(s):  
High Speed ◽  
Natural Frequencies ◽  
Pressure Fluctuations ◽  
Diameter Ratio ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Pressure Pulsations ◽  
Column Structure ◽  
Model Predictions ◽  
Computational Fluid Dynamics Cfd

This paper investigates the influence of a tapered cylinder nozzle (TCN) on pressure pulsations in a high-speed reciprocating compressor piping system. Numerical methods, the 3D frequency-domain finite element method (FEM) and the 3D time-domain computational fluid dynamics (CFD) were used to separately calculate gas column natural frequencies and pressure pulsations. With favorable agreement between model predictions and experimental data, it is concluded from predictions that an installed TCN changes both the values and distribution of frequencies because installation of a TCN filter can alter gas column structure in the piping system. The order of frequency dominated by cylinder nozzle response increases sharply as the TCN diameter ratio increases and the TCN length to diameter ratio decreases. Pressure fluctuations can be effectively attenuated in piping system under different functioning conditions, e.g. variable compressor speeds and variable discharge pressures.

Comparison of Conventional and Pontic Fixed Partial Dentures Over Implants Using the Finite Element Method: Three-Dimensional Analysis of Cortical and Medullary Bone Stress

2020 ◽  
Vol 46 (3) ◽  
pp. 175-181
Author(s):  
Marcelo Bighetti Toniollo ◽  
Mikaelly dos Santos Sá ◽  
Fernanda Pereira Silva ◽  
Giselle Rodrigues Reis ◽  
Ana Paula Macedo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Medullary Bone ◽  
Principal Stresses ◽  
Bone Stress ◽  
Bone Damage ◽  
Rehabilitation System ◽  
Minimum Requirements

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.

Towards Predicting Relative Belt Edge Endurance With the Finite Element Method

1990 ◽  
Vol 18 (4) ◽  
pp. 216-235 ◽  
Author(s):  
J. De Eskinazi ◽  
K. Ishihara ◽  
H. Volk ◽  
T. C. Warholic
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Shear Deformations ◽  
Element Analysis ◽  
Vertical Loading ◽  
Predicted Values ◽  
Element Method

Abstract The paper describes the intention of the authors to determine whether it is possible to predict relative belt edge endurance for radial passenger car tires using the finite element method. Three groups of tires with different belt edge configurations were tested on a fleet test in an attempt to validate predictions from the finite element results. A two-dimensional, axisymmetric finite element analysis was first used to determine if the results from such an analysis, with emphasis on the shear deformations between the belts, could be used to predict a relative ranking for belt edge endurance. It is shown that such an analysis can lead to erroneous conclusions. A three-dimensional analysis in which tires are modeled under free rotation and static vertical loading was performed next. This approach resulted in an improvement in the quality of the correlations. The differences in the predicted values of various stress analysis parameters for the three belt edge configurations are studied and their implication on predicting belt edge endurance is discussed.

Disorganization of a hole tone feedback loop by an axisymmetric obstacle on a downstream end plate

2014 ◽  
Vol 757 ◽  
pp. 908-942 ◽  
Author(s):  
K. Matsuura ◽  
M. Nakano
Keyword(s):  
Nozzle Exit ◽  
Passive Control ◽  
Control Method ◽  
Three Dimensional ◽  
Acoustic Power ◽  
Shear Layers ◽  
Mean Velocity ◽  
End Plate ◽  
Air Jet ◽  
Practical Engineering

AbstractThis study investigates the suppression of the sound produced when a jet, issued from a circular nozzle or hole in a plate, goes through a similar hole in a second plate. The sound, known as a hole tone, is encountered in many practical engineering situations. The mean velocity of the air jet $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}u_0$ was $6\text {--}12\ \mathrm{m}\ {\mathrm{s}}^{-1}$. The nozzle and the end plate hole both had a diameter of 51 mm, and the impingement length $L_{im}$ between the nozzle and the end plate was 50–90 mm. We propose a novel passive control method of suppressing the tone with an axisymmetric obstacle on the end plate. We find that the effect of the obstacle is well described by the combination ($W/L_{im}$, $h$) where $W$ is the distance from the edge of the end plate hole to the inner wall of the obstacle, and $h$ is the obstacle height. The tone is suppressed when backflows from the obstacle affect the jet shear layers near the nozzle exit. We do a direct sound computation for a typical case where the tone is successfully suppressed. Axisymmetric uniformity observed in the uncontrolled case is broken almost completely in the controlled case. The destruction is maintained by the process in which three-dimensional vortices in the jet shear layers convect downstream, interact with the obstacle and recursively disturb the jet flow from the nozzle exit. While regions near the edge of the end plate hole are responsible for producing the sound in the controlled case as well as in the uncontrolled case, acoustic power in the controlled case is much lower than in the uncontrolled case because of the disorganized state.

scholarly journals The effect of the outlet angle β2 on the thermomechanical behavior of a centrifugal compressor blade

2020 ◽  
Vol 29 (1) ◽  
pp. 1-8
Author(s):  
Ahmed Allali ◽  
Sadia Belbachir ◽  
Ahmed Alami ◽  
Belhadj Boucham ◽  
Abdelkader Lousdad
Keyword(s):  
Mechanical Behavior ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Complex Form ◽  
Compressor Blade ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Mechanical Fatigue ◽  
Outlet Angle ◽  
The Impact

AbstractThe objective of this work lies in the three-dimensional study of the thermo mechanical behavior of a blade of a centrifugal compressor. Numerical modeling is performed on the computational code "ABAQUS" based on the finite element method. The aim is to study the impact of the change of types of blades, which are defined as a function of wheel output angle β2, on the stress fields and displacements coupled with the variation of the temperature.This coupling defines in a realistic way the thermo mechanical behavior of the blade where one can note the important concentrations of stresses and displacements in the different zones of its complex form as well as the effects at the edges. It will then be possible to prevent damage and cracks in the blades of the centrifugal compressor leading to its failure which can be caused by the thermal or mechanical fatigue of the material with which the wheel is manufactured.

Research on the Reliability of Box for Gear Test Bed

2011 ◽  
Vol 121-126 ◽  
pp. 1744-1748
Author(s):  
Xiang Yang Jin ◽  
Tie Feng Zhang ◽  
Li Li Zhao ◽  
He Teng Wang ◽  
Xiang Yi Guan
Keyword(s):  
Power Flow ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Test Bed ◽  
Kinematics Simulation ◽  
Beveloid Gears ◽  
Overall Performance

To determine the efficiency, load-bearing capacity and fatigue life of beveloid gears with intersecting axes, we design a mechanical gear test bed with closed power flow. To test the quality of its structure and predict its overall performance, we establish a three-dimensional solid model for various components based on the design parameters and adopt the technology of virtual prototyping simulation to conduct kinematics simulation on it. Then observe and verify the interactive kinematic situation of each component. Moreover, the finite element method is also utilized to carry out structural mechanics and dynamics analysis on some key components. The results indicate that the test bed can achieve the desired functionality, and the static and dynamic performance of some key components can also satisfy us.

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