Thermal Management Research for Power Generation. Delivery Order 0002 - Volume 2: Closed-Loop Spray Cooling of High-Power Semiconductor Lasers.

摘要

A closed-loop spray cooling test setup is established for the cooling of high-power diode lasers. Eight miniature nozzles in a multinozzle plate are used to generated a spray array targeting at a 1 by 2 cm2 cooling surface. FC- 87, FC-72, methanol and water are used as the working fluids. Thermal performance data for the multinozzle spray cooling in the confined and closed system are obtained at various operating temperatures, nozzle pressure drops (from 0.69 bar to 3.10 bar), and heat fluxes. It is demonstrated that the spray cooler can reach the critical heat fluxes up to 90 W/cm2 with fluorocarbon fluids and 490 W/cm2 with methanol. For water, the critical heat flux is higher than 500 W/cm2. It is found that air purposely introduced in the spray cooling system with FC-72 fluid has a significant influence on heat transfer characteristics of the spray over the cooling surface. A semiempirical correlation of CHF is presented using the present experimental data for the multinozzle spray cooling in the confined and closed system without air.