Theoretical and Experimental Research on The Optimal Displacement Ratio of Rotary Two-Stage Inverter Compressor With Vapor Injection

Displacement ratio is one of the most important parameters of designing rotary two-stage inverter compressor with vapor injection, which decides the COP (Coefficient of Performance) of the compressor. The optimal displacement ratio can bring about the highest COP. The mathematical model of the optimal displacement ratio of rotary two-stage inverter compressor with vapor injection has been developed and verified with the test data. It can be seen from theoretical and experimental research that the optimal displacement ratio of compressors in different working conditions can be obtained accurately by the mathematical model introduced in this paper

Research on Two-stage Rotary Compressor with Refrigerant Injection for Cold Climate Heat Pump

As an promising heating application of environmental conservation and energy conservation, air-source heat pump systems has been spreading. However, conventional heat pump systems have problems remaining, such as inadequate heating capacity and reduced performance under low environmental temperature condition. To solve these problems, we developed a two-stage rotary compressor for household R32 air-source heat pump system. We analyzed the thermodynamic characteristics of two-stage rotary compressor with refrigerant injection used in heat pump system with economizer. It is found that the two-stage rotary compressor can enhance heating capacity and performance of R32 heat pump under cold climate markedly

Numerical Analysis and Optimization for Hydrodynamic Lubrication in Journal Bearings of Rotary Compressor

Based on the average Reynolds’ equation of hydrodynamic lubrication, the axis locus and the minimum oil film thickness of the journal bearings under the dynamic load were numerically solved in this paper, and the movement and bearing characteristics of the compressor bearings at different rotation speeds were analyzed to evaluate the influence of the friction loss of the journal bearings on the performance of the rotary compressor. The simulation results indicated that the minimum oil film thickness of the sub bearing is smaller than the critical oil film thickness at low rotation speed (n ≤ 1800 rpm), therefore, the friction power increases significantly with the decrease of rotation speed. The effects of width-diameter ratio, clearance and viscosity of lubricating oil on the improvement of minimum oil film thickness were further analyzed. By optimizing the width-diameter ratio of the bearing, the load carrying capacity of the oil film is improved, and the friction power of sub bearing reduces by more than 80%. The experimental results showed that the performance of rotary compressor can be improved by more than 1% at low rotation speed

The Tribological Behavior of Cast Iron by Laser Surface Texturing under Oil-Lubricated Initial Line Contact for Rotary Compressor

The tribological behaviors of cast iron by laser surface texturing were experimentally compared with the behavior of untextured by unidirectional rotary sliding friction and wear tests under oil-lubricated initial line contact. The friction coefficient and temperature rise were analyzed with the increasing load applied by block-on-ring tests. In addition, the wear loss and wear mechanism were also investigated through the surface topographies analysis. The results showed that the tribological improvement strongly depended on the contact form. For the oil-lubricated initial line contact in this work, the textured surface showed a better frictional advantage with a lower friction coefficient and lower temperature rise. The hydrodynamic effect enhanced the load-carrying capacity of the oil film and increased the film thickness. The friction coefficients were 11~64% lower than those on the untextured one. Meanwhile, the textured surface deteriorated the wear behavior due to the coupling effect between the micro-cutting effect of the texture edges and the material deformations of the counter surface. The material loss induced by abrasive wear and fatigue wear was the dominant wear mechanism. Namely, the laser surface texturing improved the friction properties but reduced the wear resistance