Biomorphous Silicon Carbide as Novel Loop Heat Pipe Wicks

Biomorphous silicon carbide is tested as a novel wick material for flat evaporator loop heat pipes (LHP). The machinable ceramic gives the possibility to improve the wick performance by macroporous channel networks without closing the structure inherent microporosity. A minimum thermal resistance of 0.4236 degrees CW-1 is obtained for unmodified SiC at a power input of 200W. Modification with channels parallel to the evaporating surface results in an improved thermal resistance of 0.3792 degrees CW-1. Modification with channels perpendicular to the evaporating surface increases the thermal resistance to 0.4469 degrees CW-1, but reduces the necessary heat load for stable start-up from 50 to 25W.