Variable Cross-section Heat Transfer Enhancement Surface Design And Experimental Studies Based On Additive Manufacturing

With the development of electronic technology,electronic devices have become highly integrated,resulting in increased heat generation.Excessive temperatures can lead to performance suppression and reduced reliability,making heat dissipation a top priority in enhancing performance.Air-cooled heat dissipation is still the most common form,especially in aviation electronic equipment.Therefore,research on efficient fin forms has broad application prospects.According to the general theory of the straight fin,the variable cross-section fin can not only improve the rib efficiency but also reduce the flow resistance.Due to the limitation of traditional manufacturing technology,it is difficult to fabricate aerodynamic fin heat sink with variable section.With the development of additive manufacturing technology,it is possible to produce this heat sink.This thesis focuses on the study of an offset strip straight fin heat sink,and researches low flow resistance,high fin efficiency,and high heat transfer coefficient fin shapes.(1)Numerical simulation and experimental verification of reference samples.A reference sample was designed and numerical simulations were carried out using laminar and turbulent flow models to obtain the heat transfer coefficient and flow resistance.Next,an experimental fixture was designed to modify the wind tunnel,and after verifying its veracity,wind tunnel experiments were conducted on the reference sample to verify the reliability of the numerical simulation method.(2)Numerical simulation of heat sinks and analysis of the influence of variable cross-section fins.The flow and heat transfer characteristics of three typical offset strip straight fin heat sinks with identical structural parameters were studied using numerical simulation methods,and a comparison of the heat transfer coefficients and flow resistance on the heat sink surfaces showed that the fin shape with variable cross-section had the best heat dissipation performance.An orthogonal test was designed for the variable crosssection fin structure with different structural parameters,and data fitting was performed to obtain empirical formulas for the relationship between different structural parameters and the heat transfer factor j and the friction factor f.A range analysis was conducted on the results to identify the structural parameters that had the greatest impact on heat dissipation performance for further research.(3)Experimental verification of variable cross-section cold plate using additive manufacturing.In order to verify the empirical formula of heat transfer factor j and friction factor f,a cold plate sample was produced using additive manufacturing technology for experimental verification.The experimental results were compared with the theoretical values calculated from the empirical formulas to demonstrate the reliability of the empirical formulas.To conduct a comparative experiment,conventional straight fin cold plates were produced using the same manufacturing process.The experimental results showed that the rib shape with variable cross-section had better heat dissipation performance and was 4.28% lighter than the conventional straight-rib cold plate.This provides a technical route for lightweight and efficient heat dissipation of the heat sink.