Construction And Performance Investigation Of Novel Asymmetric Variable Wall Thickness Scroll Wraps For Scroll Compressors

The scroll compressor consists of two key components,the fixed and orbiting scrolls,whose wrap profiles mesh with each other to form a series of working chambers with periodically changing volume to realize gas compression.Therefore,the profiles of the scroll wrap play an important role in the working performance of the scroll compressor.The existing variable wall thickness scroll wraps are usually symmetric,that is,both the orbiting and fixed scroll wraps have variable wall thickness,which makes the dynamic characteristics of the orbiting scroll poor due to the large mass during rotating.In view of the above problem,a novel structure of asymmetric variable wall thickness scroll wraps and its design method were proposed in this thesis.Thickness of the orbiting scroll is constant and thickness of the fixed scroll is variable.Then,two kinds of combined profiles asymmetric variable wall thickness scroll wraps and one kind of trigonometric involute asymmetric variable wall thickness scroll wrap were obtained.Focusing on the analysis of the trigonometric involute asymmetric variable wall thickness scroll wrap,the influences of characteristic parameters on the scroll wraps were studied,and the scroll wrap with better comprehensive performance was obtained.Furthermore,the wrap head was modified,the complete meshing scroll wraps were generated and effects of modification parameters on the performance of scroll compressors were studied.Apart from this,the problem that the built-in volume ratios of two groups of working chanbers are not equal was solved.Three-dimensional numerical simulation of the novel asymmetrical variable wall thickness scroll compressor was conducted,and the flow field distribution and velocity distribution in the working chambers during the working process were obtained.Finally,the mechanical characteristics were analyzed,including the stress,deformation,gas force,moment,and centrifugal force,compared with the existing symmetric variable wall thickness scroll compressors.The results show that the proposed novel asymmetric variable wall thickness scroll wrap has good dynamic characteristic due to the constant wall thickness structure of the orbiting scroll and owns the advantage of convenient generation process.The new asymmetric variable wall thickness scroll compressor has better pressurization effect than the existing symmetric variable wall thickness scroll compressor.Under the action of temperature load and pressure load,the maximum stress of the orbiting scroll of the new structure is reduced by4.4% compared with the existing structure,and the maximum deformations of them are similar.The centrifugal force of the orbiting scroll of the new asymmetric structure is reduced by 26% compared with the existing symmetric structure,which means that the new asymmetric structure has smaller rotational inertia force and better dynamic characteristics.Therefore,the novel asymmetric variable wall thickness scroll wrap constructed in this thesis is of great significance for enriching the types of scroll wrap profiles,improving the performance of scroll compressors and promoting the development of variable wall thickness scroll compressors.