Investigation And Optimization Of The Variable Density Alternating Obliquely Truncated Microchannel

Nowadays,microelectronic devices are continuously developing towards lightweight,small size,and multi-functionality.The integration degree of devices is constantly improving,and the power density is increasing.The issue of thermal-induced reliability is exceptionally prominent,which presents a significant challenge to the high-efficiency thermal management technology of the devices.As an advanced cooling technology,microchannel heat sinks can effectively improve the efficiency of heat dissipation.Most research on microchannel heat sinks has focused on improving their heat dissipation capacity and reducing pump power loss.However,temperature uniformity is increasingly significant,as a critical parameter affecting the electrothermal performance of microelectronic devices.Temperature uniformity has become a key indicator for evaluating the performance of microchannel heat sinks.Innovating and optimizing the structure of microchannel heat sinks can enhance their heat dissipation capacity,reduce pressure drop loss,and further improve their temperature uniformity,which will help to raise their comprehensive performance.This paper proposes the variable density alternating obliquely truncated microchannel heat sink(AOTF-MC)with the main channel width of 200μm.Experimental and numerical simulation studies are conducted from two perspectives:structure study and parameter optimization.Firstly,an AOTF-MC with an overall size of 10mm×10mm×3.5mm is designed and fabricated.Its main channel width×height is 200μm×300μm.The experimental fixture and experimental platform is designed and constructed.Under a heat dissipation condition of 100W/cm2,convective heat dissipation experiments are carried out using deionized water as the cooling medium.The comprehensive heat dissipation performance of AOTF-MC and traditional rectangular microchannels(RS-MC)are compared under different Reynolds numbers using both experiments and numerical simulations.Secondly,the Taguchi method is applied to study the influence of various structural parameters of the microchannel on the average Nusselt number,friction coefficient,and uniformity of the heated surface temperature.The significance ranking of the impact of each geometric parameter on the comprehensive properties is calculated using the signal-to-noise ratio.Finally,a surrogate model is established in a continuous design space using Latin hypercube sampling and integrated learning algorithms.The surrogate model is optimized using a genetic algorithm for single-objective and multiobjective optimization,and the optimization results are compared and validated.The experimental research results indicate that(1)the uncertainty of the geometric parameters,thermal property parameters,and hydraulic performance parameters does not exceed 6%in the experiment.The obtained data results are valid;(2)with the increase of the inlet Reynolds number,the average Nusselt number and pressure drop increase,with the decrease of the thermal resistance and standard deviation of the heated surface temperature.Within the flow range adopted in the experiment,the thermal resistance varies between 0.53K/W and 0.42K/W,reflecting the excellent heat dissipation performance of AOTF-MC.The results of numerical simulation indicate that(1)increasing the inlet velocity can enhance the dispersion performance,improve the uniformity of temperature,and reduce the friction coefficient;(2)compared with the theoretical solution and experimental results,the relative error of AOTF-MC and RS-MC numerical simulation results is no more than 8%,verifying the simulation accuracy of the numerical model;(3)the overall performance of AOTFMC is superior to that of RS-MC,and with the increase of inlet velocity,the advantage of its overall performance gradually increases.At the same time,the uniformity of temperature of AOTF-MC is significantly better than that of RS-MC.AOTF-MC has important research value;(4)cooperating with the Taguchi method for orthogonal experimental design,the influence of various geometric parameters(secondary channel width,oblique angle,y-axis extension length of guide rib,guide rib width,and the level difference between adjacent secondary channels)on the average Nusselt number,bottom temperature standard deviation,and friction coefficient of AOTF-MC is efficiently studied;(5)using the obtained signal-to-noise ratio to calculate the contribution rate,the significance ranking of the influence of various geometric parameters on the performance of microchannel heat sink is achieved.The effect of each geometric parameter on the performance of AOTF-MC is revealed.The guidance and reference for the optimization of the microchannel are provided.The results of parameter optimization indicate that(1)the surrogate model obtained based on Latin hypercube sampling and ensemble learning algorithm can accurately describe the relationship between design parameters and optimization objectives;(2)multi-objective optimization based on non-dominated sorted genetic algorithm-II can significantly improve the overall performance of the microchannel heat sink.Compared with the initial design,the best compromise solution of Pareto optimal solutions obtained using the technique for order preference by similarity to an ideal solution has an average Nusselt number 21.26%higher than the initial design,as well as the friction coefficient and standard temperature deviation are 8.33%and 66.13%lower than the initial design,respectively.The performance evaluation criterion reaches 1.56,indicating a significant improvement.