Research on Design and Applications of Axial-compliance Mechanism for Scroll-type Compressors

• Main Authors: Tang, Yue-hju, 湯岳儒
• Other Authors: Hung, Ching-hua
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/18240212931779095303

博士 === 國立交通大學 === 機械工程學系 === 101 === A variable-speed scroll-type compressor (STC) with brushless DC convertor motor has become the mainstream of the technological development because of the requirements for energy-saving and environmental protection in modern high-efficiency inverter refrigeration and air conditioning systems. To overcome the problem of the volume compression efficiency change by the inverter capacity adjusting, the primary key to the solution is to solve the internal leakage problem of the variable-speed compression pump. In this study, the axial-compliance mechanism (ACM), which is composed of a backpressure regulating mechanism acting on the fixed scroll back and a suspension mechanism controlling the scroll clearance, was studied. The use of the ACM enables dynamical adjustments, which allow the scroll clearance to be maintained at a fixed optimal value in order to reduce the varying of volume compression efficiency by the internal leakage in the scroll compression chambers and the high volumetric efficiency can thus be maintained while the system load changed. Several critical techniques for accomplishing a high-performance, variable-speed low-pressure-side (LPS) STC with an ACM have been developed and investigated. First, the mathematical model of axial leakage value was constructed, and the advantages of this model were confirmed by numerical simulations and experimental validations with the developed ACM in an R22 LPS STC prototype. The experimental results showed that if the compliance mechanism is designed appropriately, the compressor can achieve a high volumetric efficiency, irrespective of the operating speed conditions. Because of the ACM, the speed range of the variable-speed scroll compressor can be extended and the efficiency can be improved by 4.7–13.5%. In addition, from the experimental observations, a fact was discovered that the ACM can also reduce the noise between the colliding components of the LPS STC. Finally, for the understanding and verification of the proposed ACM design method could be extended its application to different refrigerant STCs. Case studies of a R410A and a R744 (CO2) applications in the LPS STC prototypes was formulated in this study. Furthermore, the application of the finite element method was introduced for the ACM mechanism design changes. From the experiment results, the proposed ACM design methods can successfully applications in these different refrigerant STCs.