Study On The Influence Of Internal Fin Parameters On The Flow And Heat Transfer Performance In The Closed Cavity Of Electronic Equipment

The natural convection flow in the side heating cavity is widely used in mechanical engineering.For example,use this flow to cool computer motherboards,power transformers,nuclear reactors,and optimize building indoor ventilation and other applications.Therefore,studying the flow characteristics of natural convection in the side heating cavity is of great significance for improving and optimizing mechanical devices and building structures.Arranging fins on the inner wall of the side heating cavity is an effective and widely recognized method for improving the natural convection flow in the cavity and enhancing the convective heat transfer in the cavity;The research on enhancing the flow and heat transfer in the cavity by changing fins length,fins position and number of fins is not sufficient,Improving flow and heat transfer in the opposite heating cavity is an urgent problem in technical applications,and it is also the goal of this paper.Based on this research goal,this paper numerically simulates the effect of length,location,and number of fins on convection and heat transfer in side-heated rectangular cavities with or without internal heat sources,respectively,using Fluent software.The main contents of the study are as follows:(1)The influence of fins length and position on the convection and heat transfer in the side heating square cavity without internal heat source is investigated if only one fin is placed on the hot wall.The results show that: when the fin at the height of H/6,2H/6,3H/6,4H/6 and5H/6 from the bottom of the hot wall,the layout length is 1.5,1.0,1.0,1.0 and 1.0cm,the average Nu number of the hot wall is the largest,is 76.91,77.1,76.85,76.58 and 76.6,and the heat transfer efficiency between the hot wall and the cavity is the best.(2)When 1 centrally symmetrical fin is arranged on each cold and hot wall,the effect of changing the length and position of the fin on the flow and heat transmission in the side heating square cavity without internal heat source is also significant.The results show that when the distance between the fins on the hot wall to the bottom surface is H/6,2H/6,3H/6,4H/6 and 5H/6,and the lengths are 0.5,1.0,1.0,0.5 and 0.5cm,respectively,the average Nusselt number on the hot wall is the largest,which are 76.42,77.76,76.74,76.38 and 76.15,respectively.The heat transfer efficiency on the hot wall and the cavity is the best.Compared with the placement of only one fin on the hot wall surface,the efficiency of heating reinforcement in the heating cavity without the inner heat source is significantly reduced when one fin is arranged on each side of the cold and hot wall.(3)For the side heated square cavity with internal heat source,only one fin is placed on the hot wall surface.For the five studied positions,when the fin length is 2.5,1.5,1.0,1.0 and0.5cm,the average Nusselt number on the hot wall is the largest,which are 53.64,54.0,53.62,53.19 and 53.09,respectively.The heat transfer efficiency on the hot wall and inside the cavity is the best.However,the average Nusselt number of the heat source surface is reduced compared with when the fins are not arranged,indicating that the placement of only one fin on the hot wall will inhibit heat transmission on the heat source surface and cavity.(4)The change of fin length and position also has a significant effect on the flow and heat transmission in the side heating square cavity with internal heat source and one fin each arranged on the cold and hot wall surface.The results show that when the distance between the fins on the hot wall to the bottom surface is H/6,2H/6,3H/6,4H/6 and 5H/6,and the lengths are 2.0,1.5,1.0,1.0 and 1.0cm,respectively,the average Nusselt number on the hot wall is the largest,which are 53.26,54.03,53.76,53.59 and 53.28,respectively.The heat transfer efficiency on the hot wall and the cavity is the best.Unlike the results of no internal heat source in the side heating cavity,compared with the placement of one fin only on the hot wall surface,there is a significant increase in the efficiency of heating intensification in the heating cavity containing the internal heat source when one fin is arranged on each side of the hot wall.However,the average Nusselt number of the heat source surface is reduced compared with the fins not arranged,indicating that the placement of one fin on the cold and hot wall also inhibits heat transmission on the heat source surface and cavity.(5)Numerical simulation of convective heat transfer in a closed cavity considering wall radiation is carried out.The results show that when the wall emissivity is 0.65,the variation trend of the average Nusselt number on the hot wall surface and the average Nusselt number on the heat source surface is consistent with the variation trend of the closed cavity without considering the wall radiation.The distance between the fins on the hot wall and the bottom surface is H/6,2H/6,3H/6,4H/6 and 5H/6.When the lengths are 2.0,1.5,1.0,1.0 and 1.0cm,respectively,the average Nusselt number on the hot wall is the largest,which is 128.91,129.27,129.18,128.9 and 128.67.The average Nusselt number on the heat source surface decreases compared with that without fins.However,when the wall radiation is considered,the average Nusselt number on the hot wall and the average Nusselt number on the heat source surface are both increased in each working condition.The average Nusselt number on the hot wall is increased by about 140.67%,and the average Nusselt number on the heat source is increased by about 48.29%.