Heat exchanger of anisotropic porous structure - has tubes submerged in fibres of material of good conductivity all oriented similarly between tubes, maximising heat transfer

摘要

A heat exchanger comprises, inside an enclosure in which a first fluid circulates, a number of parallel tubes in which a second fluid circulates and a porous structure realised in a material which is a good conductor of heat. The first fluid runs through, and the tubes are submerged in, the porous structure, which is anisotropic, or oriented. It is constituted pref. by fibres e.g. of copper having the same direction between the tubes and being in thermal contact with them. The anisotropic porous structure gives a considerable improvement in the coefficient of heat transfer between the primary and secondary fluids without altering the pressure drops. in comparison with exchangers of granular porous structure in which thermal conduction is isotropic. The improvement results from the conduction of the thermal flux being oriented by the porous structure itself.