Numerical Simulation Study On Natural Convection Heat Transfer Of A New Finned Heat Sink

Heat dissipation is extremely important for the development and application of electronic equipment.Natural convection heat transfer is widely used in some specific application environments due to its advantages of no energy consumption and high reliability,such as LED lights,small base stations,etc.In this paper,the heat dissipation performance of finned heat sink is studied by numerical simulation.The results can provide some reference and theoretical guidance for solving the problem of electronic heat dissipation.The grid-independence of numerical simulations is verified by comparing the temperature of base and the average Nusselt number with different grid precisions.The correctness of the model is tested by comparing the simulation results with experimental results of other scholars.The main contents of the research are as follows:Aiming at the problem of electronic heat dissipation,a new heat sink structure with symmetric inclined fin array is proposed.The effects of fin height and longitudinal fin spacing on the relationship between Rayleigh number and Nu number are studied respectively.The influence of longitudinal fin spacing on the temperature distribution of different layout heat sinks is analyzed.The field synergy of the heat sinks with different layouts is discussed.The influence of heat sink mounting angle on the performance of heat transfer is researched.The results show that,Nu number increases linearly with increasing Ra number.When Ra number is constant,As the height of the fin increases,the Nu number gradually increases and then gradually decreases,and when the fin height reaches 40 mm,the Nu number reaches the maximum value.When the Ra number is constant,the Nu number decreases with the decrease of longitudinal fin spacing,and the shorter the longitudinal fin spacing is,the faster the Nu number decreases.As the number of fin rows increases,the upper and lower stratification phenomenon of the base temperature field becomes more and more obvious,and the region of high temperature is concentrated at the upper two corners of the plate.The fitting curve slope of Ra number with Nu number of six-row heat sinks is higher than that of four-row heat sinks,six-row heat sink has fewer zones of high temperature,and according to the analysis of field synergy,the field synergy angle of the six-row heat sink is the smallest,indicating that heat transfer effect is the best.The mounting angle has a significant effect on the heat transfer performance of heat sink.When the mounting angle is positive,the suppression of heat dissipation is stronger,and when the mounting angle is-15°,the thermal resistance is the smallest.According to the existing data,a new correlation of Nu number is obtained.For the heat dissipation problem of the cylindrical inner fin heat sink structure placed vertically.The effects of fin number,fin height and cylinder length on the effectiveness of heat sink and Nu number are studied.The effects of Nu number and the number of fins on the velocity field and the temperature field of heat sink are discussed.The results show that,as the ratio of L/D increases,the effectiveness of heat sink increases gradually;and as fin number increases,the effectiveness of heat sink increases.For a low Ra number,as fin number increases,the heat sink effectiveness is slowly increased due to the lower heat lifting force.When H/D,fin number and Ra number are given,Nu number under lower ratio of L/D is higher than that of higher ratio.As Ra number increases,the suction interaction of cylindrical heat sink increases,air flow rate increase simultaneously,which enhances the performance of heat transfer.With the increase of Ra number,there is a decrease in speed at a distance from the exit of the cylinder heat sink,and then the "chimney flow" is formed.