探討利用不同電流密度之電鍍銅表面對於去離子水 及介電溶液之噴霧冷卻熱傳影響

Abstract

本研究以不同電流密度所產生的不同微孔結構電鍍銅表面進行不同工作流體(水、Novec-7100)的噴霧冷卻實驗並探討其在單相及兩相區間的熱傳表現，本次噴霧冷卻的相關實驗參數如下：噴嘴距離測試表面高度為22 mm、噴嘴孔徑為0.51 mm、銅測試表面直徑為16 mm、工作流體採用去離子水以及介電溶液Novec-7100，有效體積流率為7.2×10-3 m3/m2‧s 以及1.2×10-3 m3/m2‧s 並利用熱電偶量測測試銅塊的溫度分布以計算實際熱通量、表面溫度等相關參數，並利用SEM 照片以及熱傳機制示意圖輔助討論實驗結果。整體而言，微孔結構表面相對於未改質的表面可以增加毛吸能力、增加表面成核點數量，使得熱傳係數以及臨界熱通量有所提升，在去離子水的噴霧冷卻實驗中，輸入電流密度為0.3 A/cm2 有最佳的熱傳係數增強效果，為未改質表面的1.29 倍，而在Novec-7100 的噴霧冷卻實驗中，輸入電流密度為1.5 A/cm2 有最佳的熱傳係數增強效果，為未改質表面的1.62 倍，最大臨界熱通量為1.66 倍。

This study conducts spray cooling experiments using copper surfaces with micro-porous structures generated under different electrodeposition current density, and investigates their heat transfer performance with different working fluids (water, Novec-7100). The parameters for these spray cooling experiments are as follows: the nozzle distance from the test surface is 22 mm, the nozzle aperture is 0.51 mm, the diameter of the copper test surface is 16 mm, and the working fluids used are deionized water and the dielectric solution Novec-7100. The effective volumetric flow rates of the DI water and Novec-7100 were 7.2×10-3 m3/m2‧s and 1.2×10-3 m3/m2‧s, respectively. The temperature distribution of the copper test blocks is measured using thermocouples to calculate actual heat flux, surface temperature, and other relevant parameters. The experimental results are discussed with the SEM images from different surfaces and schematic diagrams. Overall, compared to unmodified surfaces, microporous structured surfaces enhance wicking capabilities and increase the bubble nucleation sites, increasing the heat transfer coefficient and critical heat flux. In the spray cooling experiments using deionized water, the current density of 0.3 A/cm2 achieves the best heat transfer coefficient enhancement, 1.29 times that of the unmodified surface. In the experiments using Novec-7100, the current density of 1.5 A/cm2 results in the optimal enhancement of heat transfer coefficient, 1.62 times that of the unmodified surface, with a maximum critical heat flux of 1.66 times.