Numerical Simulation Of Centrifugal Impeller Flowfield In Heat Pump System And Structural Optimization

Nowadays, energy problem is a magnitude social problem people have to confront. Energy saving is relative to human survival and development, more and more people are convinced of essentiality of energy saving. Development of the technology of Water-to-water high-temperature heat pump with centrifugal compressor taking industrial redundant heat as low-order heat source,have an important meaning to area heating of the northern urban of our country and other heating field. Centrifugal compressor is the key part of the centrifugal compressing type heat pump. Its operational efficiency, operating mode range and security performance directly influences the performance of the whole heat pump. The impeller is thought to be the most important and complicated part in centrifugal compressor. Transformation of the shaft mechanical energy to the pressure energy of the compressed gas is realized in the impeller. It is the only way of improve the gas energy. Numerical calculation can obtain plenty of detail of flow field as well as conduct different kinds of ideal condition numerical test expediently. Researches covered a wide field, so it saved tremendous amounts of money and shortened cycles of research. Therefore, correct numerical study of the related flow field of impeller has important meaning to optimize the performance of the centrifugal compressor.In this dissertation, R123 is used to be refrigerant, existing centrifugal impeller is simulated at the base of summarizing simulative method of centrifugal compressor in china and abroad. Firstly, the control equation of the impeller machinery flow field is derived in detail, then concluded onflow model of numerical simulation on impeller flow field.Secondly, confirming geometrical shape and operating mode of impeller part of centrifugl compressor of high temperature heat pump system, simulating single passage of impeller machinery flow field at designed operating mode and variational flux mode with software—CFX, analyzing law of characteristic curve of impeller and velocity distributing of section as well as problem of secondary flow and wake in impeller outlet in flow field.Finally, amending shape of impeller at the base of primary shape, analying the relation between geometrical shape and efficiency from changing numbers of impeller, ratio of width and diameter of outlet, thickness of impeller.