LIQUID-METAL HEAT PIPES FOR FUSION APPLICATION

Liquid metal heat pipes (HP) possess excellent heat transfer character istics and are now widely used in space and atomic industries as very attractive fully autonomous devices. However, their application in mag netic field devices is restricted due to very scare data on the influe nce of magnetic field on heat transfer parameters of liquid metal HP. The main objective of the present experiments is to determine the maxi mum surface heat flux removed by HP in magnetic field. Specially desig ned tubular sodium heat pipe has the following features: capillary str ucture which consists of metallic felt in the evaporation zone and a p erforated screen in the condensation zone; the structural material is niobium alloy. Experimental set-up consists of a vacuum chamber placed between the poles of an electromagnet which can ensure magnetic field strength up to 1.5 T in the vacuum chamber. The direction of the appl ied magnetic field is transverse to the liquid metal flow in the heat pipe. The set-up provides a possibility to incline the vacuum chamber up to 45 degrees relative to the horizontal axes. The dependence of cr itical heat flux of the heat pipes as a function of magnetic field str ength up to 1.5 T has been studied. The concept of fusion reactor plas ma facing components cooled by liquid metal heat pipes is presented. ( C) 1998 Elsevier Science S.A. All rights reserved.