Design and analysis of a novel composite axial impeller for compressing water vapor as refrigerant.

摘要

In order to compress water vapor as refrigerant, most modern impeller confronts a lot of challenges since the impeller has to be made with strict material and structure requirements. This thesis investigates a novel composite axial impeller to achieve the compression goal which is also able to solve those challenges. Based on an advanced concept, this thesis realizes automatic manufacturing of a composite impeller, as well as an analysis of its mechanical properties, and rotor dynamic and aerodynamic performance analyses.;To compress water vapor as a refrigerant, the typical refrigeration cycle process is modified in such a way that the coefficient of performance is increased approximately 30%.The modified imposes requirements to rotating impellers such as rotating speed, pressure ratio and efficiency. In order to produce an impeller with satisfied mechanical properties, a CNC machine based platform is developed for automated manufacture; its mechanical properties are experimentally tested and results show that this approach is able to manufacture the quality of composite impeller as desired. A new methodology is developed to predict the composite rotating impeller's fatigue life, especially for ones with complicated geometries when aerodynamic force is not negligible. The impeller's patterns' effects, from aerodynamic views, are compared and flow structure inside of a blade-angle-optimized impeller channel shows that a serious boundary layer separation exists between 30% and 50% of impeller span zone.;The investigation brings a concept up to the table and develops a novel axial composite impeller for compressing water vapor as refrigeration. Using this axial impeller, blade angle and geometries have been optimized to prevent boundary layer separation and through investigation, it demonstrates specific pressure ratio and efficiency can be achieved to reach the goal of compressing water vapor as refrigerant.