Two-phase cooling characteristics of mono-dispersed droplets impacted on an upward-facing heated disk

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• 作者：Seyed Reza Mahmoudi<sup> ; sup><sup>smahmou3@uwo.casup> ; Kazimierz Adamiak ; G.S. Peter Castle
• 关键词：Droplet cooling ; Critical heat flux ; Weber number ; Strouhal number
• 刊名：Experimental Thermal and Fluid Science
• 出版年：2013
• 出版时间：January, 2013
• 年：2013
• 卷：44
• 期：Complete
• 页码：312-322
• 全文大小：946 K

文摘

Droplet impact cooling has been shown to be a promising method for high heat flux removal applications. Recent experimental studies have revealed that even higher heat transfer at low mass fluxes and low Weber number can be achieved with only few degrees of superheat. In the present work, mono-dispersed droplet cooling of a horizontal upward facing heated surface was investigated at low Weber numbers. The impact velocity and frequency of free falling stream of droplets were varied through changing the gap between the heated surface and tip of different capillaries, and by variation of the volumetric flow rate (0.5-4.8 cc/min). The impact velocity and droplet frequency were varied between 0.28-1.3 m/s and 0.5-5 Hz, respectively, using four different capillaries sized between 17 g and 22 g. The coolant was 25 ¡ãC deionized water and all the experiments were performed at atmospheric pressure. The time-averaged two-phase characteristic curves were obtained up to the Critical Heat Flux (CHF) regime. Through the extensive set of experiments, two separate correlations are proposed to predict the average CHFs based on the Weber in the range between 3-10 and 10-100, and Strouhal number ranged in the range between 6.35 ¡Á 10<sup>?3sup> and 3.88 ¡Á 10<sup>?2sup> and 1.81 ¡Á 10<sup>?3sup> and 3.86 ¡Á 10<sup>?2sup>, respectively. The correlation predicts the average CHFs in both regions with absolute errors less than 20 % and 25 % , respectively.