Library Subscription: Guest
Home Archives Officers Future meetings American Society of Thermal and Fluids Engineering
First Thermal and Fluids Engineering Summer Conference

ISSN: 2379-1748
ISBN: 978-1-56700-430-4

HYDRODYNAMICS AND HEAT TRANSFER OF MICRO-SCALE SURFACE FLOWS INDUCED BY TRIANGULATED DROPLET STREAM IMPINGEMENT ARRAY

DOI: 10.1615/TFESC1.mnp.012576
pages 1561-1572

Taolue Zhang
Department of Engineering Technology and Industrial Distribution, Texas A&M University, College Station, Texas, USA 77843

Jorge L. Alvarado
Texas A&M University, College Station, TX, 77843, USA

Jayaveera P. Muthusamy
Texas A&M University, College Station, TX, 77843, USA

Anoop Kanjirakat
Texas A&M University at Qatar, Education City, Doha, Qatar

Reza Sadr
Texas A&M University at Qatar, Education City, Doha


KEY WORDS: Droplet impingement cooling, micro-scale surface flow, infrared imaging, high speed imaging, Weber number

Abstract

A study of surface flow hydrodynamics and heat transfer caused by triple streams of impinging droplets arranged in a triangular array is presented. HFE-7100 was used as cooling liquid due to its low saturation point and dielectric properties, specifically tailored for electronic cooling applications. Triple streams of mono-dispersed droplets were produced using a piezoelectric droplet generator with the ability to adjust parameters such as droplet Weber number and spacing between adjacent droplet streams. A thin layer of Indium Tin Oxide was coated on a translucent sapphire substrate, which was used as a heating . High speed and infrared imaging techniques were used to characterize the hydrodynamics and heat transfer of micro-scale surface flows. Surface jet-like fluid flows were observed among the impact craters during the high frequency droplet impingement process. A transition from laminar-like to turbulent-like surface jet flows was observed by increasing droplet Weber number or decreasing horizontal impact spacing. An empirical correlation has been postulated capable of predicting the transition of surface jet flows. The effects of surface jet flow regimes on heat transfer performance are discussed. It has been found that neither strong turbulent-like nor weak laminar-like surface jet flows are favorable for heat transfer. Experimental results show that strong turbulent-like surface jet flows lead to liquid splashing, while weak laminar-like surface jet flows result in accumulation of heated liquid. Both phenomena reveal that Weber number and horizontal impact spacing are crucial heat transfer performance parameters in droplet impingement cooling.

Purchase $20.00 Check subscription Publication Ethics and Malpractice Recommend to my Librarian Bookmark this Page