Abdulmohsen O. Alsaiari
Virginia Tech, Dept. of Mechanical Engineering, Blacksburg, VA 24061-0238, USA; King Abdulaziz University, Dept. of Mechanical Engineering, Saudi Arabia
Thomas E. Diller
Virginia Tech Department of Mechanical Engineering, Blacksburg, VA, 24061, USA
Jet impingement experiments were conducted to evaluate the practicability of employing jet impingement cooling in a power plant condenser. A heated plate was subjected to jets of air pressurized out of overhead orifices. The surface temperature was maintained by controlling voltage to the heater. Convection coefficients were obtained from power and temperature measurements. The cooling performance (CP) was estimated as the ratio between heat transfer and fan power. Measurements were performed at four flow area percentages, four distance to orifice diameter ratios, three orifice diameters, two jet velocities, and two surface temperatures. Convection coefficients increased by 60% as jet velocity increased from 10 m/s to 20m/s, however, CP decreased by 80%. Convection coefficients increased by 35% as the flow area percentage increased from 1% to 3%, however, CP decreased by 48%. Moreover, CP improved by 25% when jet diameter decreased by half, and by 20% when distance to orifice diameter ratio decreased from 12 to 3.5. Highest transfer rate, with a coefficient of 179W/m2-K, was observed at 20m/s jet velocity, 3% flow area, 60°C surface temperature, 3.5 distance to orifice diameter ratio, and 0.476cm diameter. However, this corresponded to a CP ratio of 28. Highest CP ratio of 225, with a coefficient of 57W/m2-K, was observed at 10m/s jet velocity, 1% flow area, 60°C surface temperature, 3.5 distance to orifice diameter ratio. An empirical model was developed and yielded results with maximum 21% deviation from experimentation.