A Study On The Effect Of New Casing Treatment Of Engine Cooling Fans

Casing treatment is one of the sub-components of the engine air-cooling system.It directly affects the performance of the engine cooling fan.This paper gives an elaborate detail of the plug-in casing treatment.The fan simulation CFD model is built with the use of Fluent.The aerodynamic performance of fans with different layout and structure casing treatment are studied.The contents of this paper are:Firstly,the basic theory of fan design and development is introduced in details and the research of cooling fan is briefly summarized.The advantages and disadvantages of different wind-tunnels are discussed in the second chapter.The measurement methods of fan performance including mass flow,static pressure,power consumption and static efficiency are introduced.A MRF method for calculating predicting cooling fan performance is presented.The characteristics of the velocity vectors,streamlines,contours of vorticity of fan are discussed which provides a useful reference for the improving of CFD model.Based on the CFD model established above,the major work of this chapter is to analyze three issues in procedure of the improvement of predictive precision.The size of the MRF-region on predictive accuracy is studied and gives the optimum size of MRF-region.Then resolution of grids over the space between the adjacent blades where the developed vortex is discussed and gives the best structural of grids.The influence of structural deformations to performance of the fan is analyzed based on the pump laws.At last,the aerodynamic performance of fan with a rounded casing treatment,a plug-in casing treatment is analyzed.The test results show that the performance of fan with plug-in casing treatment gets worse at the stall point.A new casing treatment with fins on the ring is proposed to improve the situation.The parameters of the new casing treatment are confirmed using the CFD model.The method to improve the predictive precision described in this paper provides a useful reference for the fan simulation and the new casing treatment provides a reference for the casing design.