Dynamics analysis of a single cylinder hermetic reciprocating compressor

2018 ◽  
pp. 139-155
Author(s):  
SC Rangel ◽  
HA Navarro ◽  
Luben Cabezas-Gómes
Keyword(s):  
Stiffness Matrix ◽  
Characteristic Frequency ◽  
Displacement Vector ◽  
Dynamic Modelling ◽  
Time History ◽  
Dynamics Analysis ◽  
Reciprocating Compressor ◽  
Spring Stiffness ◽  
Resonance Frequencies ◽  
Hermetic Compressor

This paper describes a dynamic modelling of a hermetic compressor pump. The pump suspension system stiffness matrix is calculated with the suspension springs, taking into account the compressive, flexural and shearing rigidities of the springs. The model allows computing the dynamic, normalized modal, and characteristic frequency matrices, and also the displacement vector of the pump and the overall kinetic and elastic potential energies of the system due to shaking forces. The results include the dynamic behavior of a compressor pump showing time history displacements, rotations and resonance frequencies for a baseline configuration. It is also show the influence of the spring stiffness and positions, through parametric and optimization analyses.

Numerical Simulation of Thermal and Fluid-Dynamic Behaviour of Reciprocating Compressor

2000 ◽  
Author(s):  
Zhilong He ◽  
Xueyuan Peng ◽  
Pengcheng Shu
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Heat Balance ◽  
Dynamic Behaviour ◽  
Fluid Dynamic ◽  
Reciprocating Compressor ◽  
One Dimensional ◽  
Compressor Design ◽  
Suction Line ◽  
Hermetic Compressor

Abstract This paper presents a numerical method for simulating the thermal and fluid-dynamic behavior of hermetic compressors in the whole compressor domain. The model of fluid flow is developed by integrating transient one-dimensional conservation equations of continuity, momentum and energy through all of the elements from suction line to discharge line. The model describing thermal behavior is based on heat balance in the components such as muffler, connecting tubes and orifices. The calculation of the thermodynamic and transport properties for different refrigerants at various conditions has been considered, and some numerical results for a hermetic compressor are presented. The present study has demonstrated that the numerical simulation is a fest and reliable tool for compressor design.

A Study on the Simulation of Flexible Link Mechanics Based on FEM

1997 ◽  
Author(s):  
Koichi Honke ◽  
Yoshio Inoue ◽  
Eiko Hirooka ◽  
Naoki Sugano
Keyword(s):  
Stiffness Matrix ◽  
Large Displacement ◽  
Dynamics Analysis ◽  
Flexible Link ◽  
Finite Rotation ◽  
Fem Model ◽  
Elastic Vibrations ◽  
Link Structure ◽  
Geometric Stiffness ◽  
Inertia Matrix

Abstract The dynamics analysis of link structure, including elastic vibrations, is presented. The two nodes element including large displacement is developed. This element is based on the theory of finite rotation, and includes geometric stiffness. The stiffness matrix and the inertia matrix are obtained from the FEM model by the theory of Guyan’s reduction including large displacement motion. In this paper, we explain the theory of this element and show some examples of analysis.

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.

An Overview of Parameters Influencing the Performance of Hermetic Reciprocating Compressor for Domestic Applications

2018 ◽  
Vol 26 (04) ◽  
pp. 1830003
Author(s):  
K. John Samuel ◽  
R. Thundil Karuppa Raj ◽  
G. Edison
Keyword(s):  
Air Conditioning ◽  
Vital Role ◽  
Critical Parameters ◽  
Reciprocating Compressor ◽  
Refrigeration System ◽  
Numerical Techniques ◽  
Air Conditioners ◽  
Structure Interaction ◽  
Compressor Performance ◽  
Hermetic Compressor

The performance of the refrigeration system mainly depends on the hermetic compressor. Of different compressors used in the refrigeration and air conditioning industries, hermetic reciprocating compressors are still efficient and have its place in domestic applications. This paper presents a review of most critical parameters and their influence on the hermetic reciprocating compressor performance. A detailed study is done on parameters like backflow, effective force and flow areas, valve dynamic behavior, etc. This study mainly concentrated on compressor valves which influence the performance of the hermetic compressor to a much greater extent. Finally, the study reveals that these parameters are playing a vital role in influencing the performance of the refrigeration system. Advanced numerical techniques involving combining fluid flow and structural analysis involving Fluid Structure Interaction (FSI) may give a better insight of the flow physics happening inside the compressors and the effect of fluid force on valve fluttering, back pressure and dynamics characteristics can be revealed in depth to optimize the performance of the hermetic compressor for household applications involving air conditioners, refrigerators, water coolers, chillers, etc.

scholarly journals Design optimization analysis of an anti-backlash geared servo system using a mechanical resonance simulation and experiment

2021 ◽  
Vol 12 (1) ◽  
pp. 305-319
Author(s):  
Lianchao Zhang ◽  
Hongbo Liao ◽  
Dapeng Fan ◽  
Shixun Fan ◽  
Jigui Zheng
Keyword(s):  
Design Optimization ◽  
Servo System ◽  
Optimization Methods ◽  
Gear Transmission ◽  
Spring Stiffness ◽  
Mechatronic Systems ◽  
Torsional Spring ◽  
Resonance Frequencies ◽  
Simulation And Experiment ◽  
Gear Systems

Abstract. In many mechatronic systems, gear transmission chains are often used to transmit motion and power between motors and loads, especially for light, small but large torque output systems. Gear transmission chains will inevitably bring backlash as well as elasticity of shafts and meshing teeth. All of these nonlinear factors will affect the performance of mechatronic systems. Anti-backlash gear systems can reduce the transmission error, but elasticity has to be considered too. The aim of this paper is to find the key parameters affecting the resonance and anti-resonance frequencies of anti-backlash gear systems and then to give the design optimization methods of improving performance, both from element parameters and mechanical designing. The anti-backlash geared servo system is modeled using a two-inertia approximate model; a method of computing the equivalent stiffness of anti-backlash gear train is proposed, which comprehensively considers the total backlash of transmission chain, gear mesh stiffness, gear shaft stiffness and torsional spring stiffness. With the s-domain block diagram model of the anti-backlash geared servo system, the influences of four main factors on the resonance and anti-resonance frequencies of system are analyzed by simulation according to the frequency response, and the simulation analysis results dependent on torsional spring stiffness of anti-backlash gear pair and load moment of inertia variation are verified by the experiment. The errors between simulation and experimental results are less than 10 Hz. With these simulation and experiment results, the design optimization methods of improving the resonance and anti-resonance frequencies such as designing the center distance adjusting mechanism to reduce the initial total backlash, increasing the stiffness of torsional spring and lightweight design of load are proposed in engineering applications.

scholarly journals Optimization Design of Actuator Parameters in Multistage Reciprocating Compressor Stepless Capacity Control System Based on NSGA-II

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhinong Jiang ◽  
Chao Zhou ◽  
Yao Wang ◽  
Jinjie Zhang ◽  
Wenhua Liu ◽  
...  
Keyword(s):  
Control System ◽  
Multiobjective Optimization ◽  
Impact Velocity ◽  
Hydraulic System ◽  
Optimization Design ◽  
Reciprocating Compressor ◽  
Spring Stiffness ◽  
Capacity Control ◽  
Nsga Ii ◽  
The Impact

The capacity control system of reciprocating compressor has great significance for the contribution of energy conservation and emission reduction. The parameters of the actuator and hydraulic system within a reciprocating compressor stepless capacity control system play a decisive role in its control accuracy, mechanical reliability, and mechanical security. The actuators and hydraulic system parameters of the same stage are in conflict with each other. Therefore, the actuator and the multistage reciprocating compressor are studied here, specifically through multiobjective optimization using the Nondominated Sorting Genetic Algorithm (NSGA)-II. The multiobjective optimization design was performed on a two-dimensional (2D) reciprocating compressor test bench. When the spring stiffness of the first stage spring was 27358 N m−1, the spring stiffness of the second stage spring was 23315 N m−1, the inlet oil pressure was 296.62 N, the impact velocity of ejection was 0.4215 m s−1, and the total indicated power deviation was 12.05 kW; the objective functions were optimized. Compared with traditional parameters, the inlet oil pressure, spring stiffness, and impact velocity were all reduced. This parameter optimization design lays the foundations for global optimization designs for stepless capacity control systems.

Full‐wave acoustic logging: synthetic microseismograms and frequency‐wavenumber analysis

Geophysics ◽  
1985 ◽  
Vol 50 (11) ◽  
pp. 1756-1778 ◽  
Author(s):  
Denis P. Schmitt ◽  
Michel Bouchon
Keyword(s):  
Wave Field ◽  
Time Domain ◽  
Displacement Vector ◽  
Fluid Velocity ◽  
Scattered Wave ◽  
Close Relation ◽  
Spectral Energy ◽  
S Wave ◽  
Resonance Frequencies ◽  
The Time Domain

The discrete wavenumber method is used to compute synthetic full‐waveform acoustic logs in axisymmetric multilayered boreholes and to perform the frequency‐wavenumber analysis of the radiated wave field. The stress‐displacement vector is propagated through the layers using a numerically improved formulation of the Thomson‐Haskell method. In the time domain, all the trapped and interface modes overlap. On the contrary, the representations of the spectral energy density of the scattered wave field in the frequency axial‐wavenumber domain, for various radial positions of observation, allow the recognition and identification of the different wave types as well as their repartition of energy. In particular, these diagrams show the close relation between the resonance frequencies of the borehole and the significant low‐frequency energy of the pseudo‐Rayleigh modes. They also facilitate the interpretation of some of the physical phenomena which occur during the propagation in a complex borehole environment. We present the configurations of a well‐bonded and unbonded cased hole, an invaded zone, and a mudcake. For all of these models, we consider a “fast” formation in which the S-wave velocity is higher than the bore fluid velocity and a “slow” formation. The presence of an elastic tool at the center of the borehole is also investigated. The associated microseismograms, computed for a series of source‐receiver spacings, characterize in the time domain the observations previously made.

Seismic performance of ductile and nominally ductile reinforced concrete moment resisting frames. II. Analytical study

1998 ◽  
Vol 25 (2) ◽  
pp. 342-352 ◽  
Author(s):  
André Filiatrault ◽  
Éric Lachapelle ◽  
Patrick Lamontagne
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Dynamic Modelling ◽  
Time History ◽  
Reduction Factor ◽  
Major Influence ◽  
Shake Table ◽  
Analysis Model ◽  
Moment Resisting Frames ◽  
Moment Resisting

This paper is the second of two companion papers on the evaluation of the level of protection offered by ductile and nominally ductile reinforced concrete structures. In the first paper, experimental results obtained from shake table tests of two half-scale reinforced concrete moment resisting frames were reported. The first structure was designed as a ductile frame (force reduction factor R = 4) according to current Canadian standards; and the second structure incorporated only nominally ductile details (R = 2). This second paper deals with the dynamic modelling of the two structures. A simple nonlinear time-history dynamic analysis model is presented and its predictions are compared with the shake table test results. It is shown that inelastic deformations in beam-column joints have a major influence on the seismic response of the structures. Approximate modelling of these joint deformations, based on equivalent rotational springs, can provide a good correlation between numerical and experimental results.Key words: dynamic analysis, moment resisting frames, earthquakes, reinforced concrete, seismic.

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