Investigation of spray cooling: Effect of different heater surfaces under acceleration

Spray cooling characteristics under acceleration conditions for different heat transfer surfaces were experimentally investigated with the aid of an acceleration test bench. Three heater surfaces tested were the flat surface, straight fin surface and porous tunnel surface. Water was used as the coolant and sprayed onto the heater surface at various nozzle heights by nozzles having different flow rates. The results of the fundamental studies show that for all the three surfaces, flow rate as well as nozzle height affects the spray cooling performance under the acceleration condition just like it does under the stationary condition. The influence of acceleration for the three heater surfaces is different and for one specific surface the effect of acceleration is also different due to the change in flow rate or nozzle height. According to the comparison results of the heat transfer performance for three surfaces under acceleration condition, it is observed that the porous tunnel surface has the best performance in all tests, followed by the flat surface in most tests. While for a certain case with a low flow rate and low nozzle height, the spray cooling capability for straight fin surface is better than flat surface.