تحليل جريان و انتقال حرارت در ميكرو كانال مثلثي جاذب حرارت به كمك تئوري ساختاري

چكيده انگليسي :

72 Heat and Fluid Flow Analysis in Triangle Microchannel Heat Sinks using Constructal Theory Molood Mardani Molood Mardani@me iut ac ir 13th September 2014 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mohammad Reza Salimpour salimpour@cc iut ac irAbstract In the last few decades scientific developments and daily increment needs for design and manufacturing ofthe smaller devices with stronger capability have changed international public direction of the investigations technology and industry for using of new devices in micro and nano dimensions These devices are used fordifferent aspects such as electronic and cooling of the circuit which are applied in design and manufacturing ofthe computers and electro mechanic systems Inasmuch as working condition of this equipment is directly relatedto its temperature keeping it in the safe temperature limitation is vital Many different methods have beenproposed to improve the cooling process of the electronic systems with massive heat flux production andcompacted size Among these methods micro channel heat sinks have attracted more glances because of the highheat transfer coefficient and low need of cooling fluid Different algorithms and methods are used fordimensional characteristics optimization of the micro channels Contructal theory is one of these methods In the first parts of the present project some aspects of constructal theory and also its usage in micro channelsand advanced manmade equipment have been presented In the second section optimum geometry of the trianglemicro channels with the side angles of 30 45 and 60 degree has been determined in such a way that trianglemicro channels configuration would have maximum heat transfer in the unit volume As optimal dimensions wereindependent of the array configuration the numerical simulation was performed on a unit cell Numericaloptimization for Triangular cross section with different side angles was performed Based on the results of thisinvestigation some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heattransfer per unit volume In addition to examining the effect of pressure drop on these parameters it was showedthat among the different geometries of this study Triangular cross section with the side angle of 60o has the mostefficiency for a given volume In the fourth section triangle micro channel heat sinks are geometrically optimizedfinding the highest heat conduction of channels The cross sectional areas of the mentioned micro channels canchange regarding to the degrees of freedom i e the aspect ratio and the solid volume fraction Actually thepurpose of the geometric optimization is to determine the optimal values of these parameters in such a way thatthe peak temperature of the wall is minimized The effects of solid volume fraction and pressure drop upon theaspect ratio hydraulic diameter and peak temperature of the mentioned micro channels are investigated Moreover these micro channel heat sinks are compared with each other at their optimal conditions The optimalshapes of all triangle channels were achieved numerically and compared with the approximate results obtainedfrom scale analysis which good agreements were observed In the last section in addition to the externalstructure internal structure of the micro channel was allowed to vary In fact the optimum possible geometry ofthe micro channel heat sink was acquired numerically considering another degree of freedom of the micro channel heat sink It was noteworthy that the effect of variation of coolant fluid thermophysical properties on thecharacteristics of fluid flow and heat transfer was also considered Key wordsConstructal theory Triangle micro channel Heat sink Optimization

مرداني، مولود

تحليل جريان و انتقال حرارت در ميكرو كانال مثلثي جاذب حرارت به كمك تئوري ساختاري

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