CONSTRUCTION AND PERFORMANCE RESEARCH OF VARIABLE CROSS-SECTION SCROLL PROFILE USING THE BASE CIRCLE INVOLUTE

Caisheng Hou, Yu Liu, Jinhu Li, Haroon Rasheed

ABSTRACT:The use of variable cross-section scroll profile is one of the effective ways to improve the performance of the scroll compressor. However, the existing variable cross-section scroll profiles have many disadvantages, such as difficult processing and unstable performance. For this reason, this paper adopted the base circle involute with stable performance and easy processing characteristics to construct a new type of variable cross-section scroll profile, and established the basic geometric theory of the profile. At the same time, two important indexes of volumetric performance, namely compression ratio and radial leakage line length, and a key index of mechanical performance, that is axial gas force, were introduced to evaluate its performance quantitatively. The results show that under the same basic parameters, compared with the equal cross-section profile formed by a single base circle involute as well as the traditional variable cross-section profile formed by the base circle involute, higher-order curve and base circle involute or circular arc, the volumetric performance and mechanical performance of the newly constructed variable cross-section profile are more advantageous, the compression ratio increased by 28.62%, 16.51% and 7.58% respectively; The length of radial leakage line is shortened by 26.56%, 16.37% and 14.23% respectively; The axial gas force is also significantly reduced, especially for the profile without the introduction of higher-order curve, the change range of the axial gas force is obviously smaller. The research broadens the design concept of the scroll profile, enriches the types of existing variable cross-section scroll profiles, and provides a certain theoretical basis for improving the performances of the scroll compressor.

Keywords : Scroll compressor, base circle involute, variable cross-section scroll profile, volumetric performance, axial gas force