A Simulation Study on Translational Piston Air Compressor

2011 ◽  
Vol 328-330 ◽  
pp. 628-632
Author(s):  
Kui Hua Geng ◽  
Meng Tang ◽  
Hong Dong Yu ◽  
Ai Nong Geng ◽  
Shi Guang Du
Keyword(s):  
Simulation Study ◽  
Relative Velocity ◽  
Friction And Wear ◽  
Kinetic Characteristic ◽  
Translational Motion ◽  
Piston Compressor ◽  
Working Principle ◽  
Rolling Piston ◽  
Rotary Speed ◽  
Conventional Rolling

The structure and working principle of a new translational piston compressor was introduced in this paper. Its piston works in a way of translational motion, hence reduces the piston’s relative velocity to cylinder and cap, as well as friction and wear. In order to avoid vane detaching from piston, simulations were carried out regarding the pre-tightening spring and an optimal preload of the spring was obtained. By analyzed and compared to conventional rolling piston compressor in term of contact force between vane and piston, it was pointed out that the new compressor possessed advantage of kinetic characteristic and is more suitable for the situation of high rotary speed.

An Introductory and Analysis of the Stationary Blade Rotary Compressor

2011 ◽  
Vol 317-319 ◽  
pp. 2063-2068
Author(s):  
Ai Nong Geng ◽  
Kui Hua Geng ◽  
Xin Mo Li
Keyword(s):  
Research Result ◽  
Piston Compressor ◽  
Friction Reduction ◽  
Chamber Pressure ◽  
Rotary Compressor ◽  
Structure Characteristics ◽  
New Type ◽  
Working Principle ◽  
Rolling Piston ◽  
Conventional Rolling

A new type of stationary blade rotary compressor is developed to overcome the rolling piston compressor’s weaknesses such as severe leaking loss and friction waste. The new compressor has unique sealing structures and friction-reducing techniques, featuring in that the compressor adopts a stationary blade whose out-end is hermetically fastened to the cylinder’s inner wall and the blade’s two side-ends are hermetically fastened to the end-covers which respectively set in both ends of the cylinder. Due to that the cylinder, the blade and the end-covers all are closely fitted to each other, the leakage and friction occurred from these parts are completely eliminated. This paper introduces the compressor’s working principle and structure characteristics, deduces the calculation formulas for displacement volume, chamber pressure and thermodynamic properties, and discusses the design principles of compressor structure parameters and what effects these parameters have on leakage and friction. The research result shows that the stationary blade compressor, in comparison with the conventional rolling piston compressor, has displayed some unique advantages in seal property, friction reduction, manufacturing and assembling techniques.

The motion of rotating cylinders sliding on pebbled ice

2000 ◽  
Vol 77 (11) ◽  
pp. 847-862 ◽  
Author(s):  
MRA Shegelski ◽  
M Reid ◽  
R Niebergall
Keyword(s):  
Thin Film ◽  
Liquid Film ◽  
Contact Area ◽  
Relative Velocity ◽  
Thin Liquid Film ◽  
Center Of Mass ◽  
Translational Motion ◽  
Rotating Cylinder ◽  
Outer Edge ◽  
Slow Rotation

We consider the motion of a cylinder with the same mass and sizeas a curling rock, but with a very different contact geometry.Whereas the contact area of a curling rock is a thin annulus havinga radius of 6.25 cm and width of about 4 mm, the contact area of the cylinderinvestigated takes the form of several linear segments regularly spacedaround the outer edge of the cylinder, directed radially outward from the center,with length 2 cm and width 4 mm. We consider the motion of this cylinderas it rotates and slides over ice having the nature of the ice surfaceused in the sport of curling. We have previously presented a physicalmodel that accounts for the motion of curling rocks; we extend this modelto explain the motion of the cylinder under investigation. In particular,we focus on slow rotation, i.e., the rotational speed of the contact areasof the cylinder about the center of mass is small compared to thetranslational speed of the center of mass.The principal features of the model are (i) that the kineticfriction induces melting of the ice, with the consequence that thereexists a thin film of liquid water lying between the contact areasof the cylinder and the ice; (ii) that the radial segmentsdrag some of the thin liquid film around the cylinder as it rotates,with the consequence that the relative velocity between the cylinderand the thin liquid film is significantly different than the relativevelocity between the cylinder and the underlying solid ice surface.Since it is the former relative velocity that dictates the nature of themotion of the cylinder, our model predicts, and observations confirm, thatsuch a slowly rotating cylinder stops rotating well before translationalmotion ceases. This is in sharp contrast to the usual case of most slowlyrotating cylinders, where both rotational and translational motion ceaseat the same instant. We have verified this prediction of our model bycareful comparison to the actual motion of a cylinder having a contactarea as described.PACS Nos.: 46.00, 01.80+b

Simulation Study of the Hydraulic System of Concrete Pumping Truck Based on AMESim

2012 ◽  
Vol 170-173 ◽  
pp. 1920-1925
Author(s):  
Chang Ge Fan ◽  
Fa Lin Zeng ◽  
De Hua Li ◽  
Lei Liu
Keyword(s):  
Simulation Study ◽  
Hydraulic System ◽  
Hydraulic Cylinder ◽  
Hydraulic Shock ◽  
Buffer Effect ◽  
Concrete Pumping ◽  
Working Principle ◽  
Simulation Results ◽  
The Relationship ◽  
Buffer Structure

The working principle of concrete pumping hydraulic system was analyzed. And base on the AMESim software, the complete simulation model of concrete pumping hydraulic system was built. A simulation was made to get the dynamic characteristics curve of hydraulic cylinder velocity and displacement at some specific conditions. The simulation results indicate that the model is reasonable. Comparative simulations of the pumping hydraulic system with different positions of buffer structure were carried out to study the relationship between buffer effect and the buffer position which can be used to provide theory basis for deeper study of the hydraulic shock.

scholarly journals The Motion of Rapidly Rotating Curling Rocks

1999 ◽  
Vol 52 (6) ◽  
pp. 1025 ◽  
Author(s):  
Mark R. A. Shegelski ◽  
Ross Niebergall
Keyword(s):  
Liquid Film ◽  
Relative Velocity ◽  
Thin Liquid Film ◽  
Translational Motion ◽  
Slow Rotation ◽  
Kinetic Friction ◽  
Centre Of Mass ◽  
Ice Surface ◽  
Translational Speed ◽  
Careful Comparison

We present a physical model that accounts for the motion of rapidly rotating curling rocks. By rapidly rotating we mean that the rotational speed of the contact annulus of the rock about the centre of mass is large compared with the translational speed of the centre of mass. The principal features of the model are: (i ) that the kinetic friction induces melting of the ice, with the consequence that there exists a thin film of liquid water lying between the contact annulus of the rock and the ice; (ii ) that the curling rock drags some of the thin liquid film around the rock as it rotates, with the consequence that the relative velocity between the rock and the thin liquid film is significantly different to the relative velocity between the rock and the underlying solid ice surface. Since it is the former relative velocity which dictates the nature of the motion of the curling rock, our model predicts some interesting differences between the motions of slowly versus rapidly rotating rocks. Of principal note is that our model predicts, and observations confirm, that rapidly rotating curling rocks stop moving translationally well before rotational motion ceases. This is in sharp contrast to the usual case of slow rotation, where both rotational and translational motion cease at the same instant. We have verified this and other predictions of our model by careful comparison with the motion of actual curling rocks.

Dynamics and Optics of Bubble Tracking Velocimetry for Airflow Measurement

2007 ◽  
Author(s):  
Tetsushi Kanda ◽  
Yuichi Murai ◽  
Yuji Tasaka ◽  
Yasushi Takeda
Keyword(s):  
Relative Velocity ◽  
Particle Tracking Velocimetry ◽  
Cross Correlation ◽  
Fine Particles ◽  
Translational Motion ◽  
Basic Research ◽  
Velocity Vector Field ◽  
Large Spatial Scale ◽  
Soap Bubbles ◽  
Quantitative Visualization

Availability of particle tracking velocimetry (PTV) that is applied to movie images of soap bubbles in airflow is investigated experimentally. This study is positioned as a basic research for measuring environmental flow with a large spatial scale, such as flows around building, trees, and near-ground airflow boundary layer. Instead of solid fine particles, soap bubbles are used as the airflow tracer for reducing environmental impact. Typical bubble size provided by the present bubble generator is controlled around 20mm, at which the bubbles obviously have relative velocity to the airflow. We report three topics on the bubble tracking velocimetry (BTV) in this paper: 1) optics of bubble-imaging for quantitative visualization, and application to 3-D visualization using color illumination, 2) theoretical estimation of bubble’s relative velocity to airflow based on an equation of bubble’s translational motion, 3) comparison of velocity vector field obtained by the BTV with that from cross-correlation PIV applied for smoke image. For the latter two topics, airflow around a NACA airfoil is chosen as the target of BTV measurement since it causes significant slip motion of soap bubbles from the airflow that accompanies shear rate, convective acceleration, pressure gradient, and separation.

Surface Topography and Friction Dynamics in Brake Systems Described by a Cellular Automaton

2005 ◽  
Author(s):  
M. Mueller ◽  
G. P. Ostermeyer
Keyword(s):  
Friction Coefficient ◽  
Kinetic Energy ◽  
Cellular Automata ◽  
Relative Velocity ◽  
Friction And Wear ◽  
Normal Load ◽  
Friction Behavior ◽  
Plastic Deformations ◽  
Parameter Dependent ◽  
Friction Dynamics

For the description of a friction event it is necessary to understand the friction coefficient μ as a process-parameter dependent not only on the surface-structure but also for instance on the relative velocity, normal load, temperature and the event itself. In brake systems, for example, growing and destroying processes of hard thin patches determine the friction power and the transfer of kinetic energy into heat and plastic deformations, such as wear. So the interaction of friction and wear is given by an equilibrium of flow of different processes resulting in growing effects or lowering effects on the friction coefficient itself [2]–[4]. The aim of this paper is to show the detailed interaction of this topographical dynamics and the friction behavior with the Method of Cellular Automata.

Experimental investigation on a two-stage CO2 compressor with high back pressure

2011 ◽  
Vol 226 (7) ◽  
pp. 1811-1820
Author(s):  
Zhaogang Qi ◽  
Jun Yang ◽  
Jiangping Chen ◽  
Haifeng Zhang ◽  
Li Zhang
Keyword(s):  
Compression Ratio ◽  
Piston Compressor ◽  
Back Pressure ◽  
Volumetric Efficiency ◽  
Mean Deviation ◽  
Two Stage ◽  
Second Stage ◽  
Two Samples ◽  
Rolling Piston ◽  
Discharge Pressure

In this article, two samples of two-stage rolling piston CO2 compressors with and without intercooler are developed and experimentally studied. These CO2 compressors are high back-pressure compressors, which mean the pressure inside compressor shell is the discharge pressure of the second stage. A test rig was designed to measure the performance and efficiency of this compressor. The test results show that the suction vapor temperature at the second stage inlet pipe has few influences on the performance and efficiency of the first compressor sample with intercooler. The volumetric efficiency linearly decreases with the increase of compression ratio of the suction and discharge pressure, and the volumetric efficiency can maintain in a relative constant range during a wide compression ratio changes in this high back-pressure design. There exists an optimum compression ratio for each suction pressure at the first stage, where the compressor isentropic efficiency is maximum. A generalized volumetric efficiency correlation for two-stage CO2 rolling piston compressor as a function of compression ratio is proposed and it can describe 100% of the test data within ±5.0% with a mean deviation of 1.7%. This would be helpful as a guide for designing such type compressor.

An effective experimental method for identifying radiated noise of different angular ranges for the rolling-piston compressor

2008 ◽  
Vol 222 (12) ◽  
pp. 2409-2417 ◽  
Author(s):  
Z Huang ◽  
W Jiang ◽  
H Zhang ◽  
C Liu ◽  
H Jin ◽  
...  
Keyword(s):  
Experimental Method ◽  
Noise Level ◽  
Angular Position ◽  
Piston Compressor ◽  
Low Noise ◽  
Discharge Process ◽  
Transform Method ◽  
Starting Position ◽  
Rolling Piston ◽  
Low Noise Design

In the traditional analysis method of noise signals, it is very difficult to relate the overall noise from compressors to the angular position. The experimental method of separating the overall noise of different angular ranges is carried out at the real conditions. The starting position of the rotary piston is labelled with vane displacement and the test signals are synchronously sampled. Experimental results are analysed through fast Fourier transform method based on different angular ranges, which displays the following useful conclusions. The experiment technology could effectively identify the angular ranges for the frequency bands with prominent noise level; for the experimental rolling-piston compressor, the vibration, and sound pressure level of the discharge process (210–360 angular degrees) are the largest above the frequency 500 Hz. The discharge process is divided into three parts, where the final part contributes a little to the overall noise level when compared with the other two stages. Pressure pulsation is an important source of vibration and noise and its suppression of peak frequencies is the key of low-noise design of the compressor.

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