The present investigation focuses on studying the performance of three specially designed surfaces in flow boiling heat transfer. The surfaces are prepared by drilling holes of specific sizes using laser ablation drilling. The heat transfer characteristics for three laser drilled enhanced surfaces, and a smooth surface are obtained by collecting experimental data for flow boiling of subcooled water over heater surfaces with different matrix of holes. The matrix of laser etched cavities are as follows: Surface 1 9.0um diameter holes spaced at 58.4um Surface 2 - 3.7um diameter holes spaced at 38.6um Surface 3 - 3.7um diameter holes spaced at 58.4um Polished Surface - polished with a polishing wheel with 5.0um solution. By varying the hole sizes and density in a systematic way, some insight is obtained in the flow boiling heat transfer mechanism on these enhanced surfaces. The experimental apparatus consisted of a 3 mm x 40 mm flow channel with a circular heater of 9.5 mm mounted in the center of the lower wall. The heater is instrumented with thermocouples to provide a measurement of the surface temperature and heat flux at the heater surface. The experiments are conducted for two subcooling temperature values, 5 K and 10 K at atmospheric pressure. It has been observed that the size of the holes plays a major role in the heat transfer characteristics of the surface. An order of magnitude enhancement in performance over a polished surface is obtained with the augmented surfaces tested in this investigation.
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Department, Program, or Center
Mechanical Engineering (KGCOE)
Fogarty, Ryan, "Flow boiling heat transfer characteristics on structured surfaces" (1999). Thesis. Rochester Institute of Technology. Accessed from
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