Research Of The Tip Clearance Effects On The Performance Of Water Cooled Plate Fin Heat Sink

In recent years,with the trend of high integration and high performance of electronic components,the heat generation of electronic devices has become larger,thus higher requirements have been placed on the heat dissipation capabilities of heat exchangers.As the structure is the simplest,plate fin heat sinks are widely used in various applications.In order to make better use of the advantages of plate fin heat sinks,many scholars have been working on optimizing the heat transfer ability through changing their structural parameters.However,the heat dissipation capacity of the heat exchanger is not the higher,the better,because the increase in heat transfer capacity is generally accompanied by an increase in the flow resistance of the heat exchanger,which will increase the energy required to drive the flow of heat transfer refrigerant,and that would decrease the economic benifits of the heat exchanger.So the flow resistance is also an important factor to evaluate the overall performance of the heat exchanger.The CFD tool,which is economical,time-saving and reliable,is more and more commonly used during the optimization processes.This paper combines the experimental and CFD simulation methods to study the thermal and fluid performance in the presence of the tip clearance on a plate fin heat exchanger with water as the working fluid,the inherent mechanisms and laws that produce this effect are also studied,which could provide a reference for the future optimal design of flat ribbed heat exchangers.The main research work and conclusions of this paper are:(1)The presence of the tip clearance will cause some part of the water that originally flowed into the inter-fin flow channel,finally enters the top channel with less flow resistance,and will not participate in the convection heat transfer.Therefore,the heat sink performance and overall pressure of the plate fin heat sink will both decreased.(2)Effect of tip clearance on the thermal and hydrodynamic performance has been studied,its corelation with the fin height,fin spacing and volume flow rate has also been quantificationally researched.(3)Within the scope of the research objects in this paper,the presence of the top void is always favorable,because the reduction in pressure drop is always greater than the loss of heat transfer capacity,that is,in the presence of the tip clearance,a small part of the heat transfer capacity is lose in exchange for a great increase in fluid flow performance;(4)At the end of the paper,an empirical correlation formula of Nu number was given,and through comparison,it was proved that the modified correlation was suitable for the research objects in this study.