Spray cooling of high power diode laser

Spray cooling experiments were performed on the heater with different micro-structured surfaces. A smooth surface was also tested for comparison. The micro-structures consisted of uniform porous tunnels with different size, and tests were conducted in an open system with ammonia as the working fluid. When the heat flux was 300 W/cm2, the surfaces temperature was kept below 28 ℃. This result indicated that ammonia was a optional fluid for diode laser cooling application. Moreover, the uniform micro-structured surfaces offered significant performance enhancement of heat transfer. At 511.5 W/cm2, heat transfer coefficient reached to 346 701.1 W/(m2℃) which corresponded to 83.9% increase over smooth surface.