Lightweight heat-exchanger suitable for aircraft - with some aluminium parts replaced by high temp. metal to reduce stress due to high temps. and pressures

摘要

Lightweight heat exchanger of aluminium or (alloy) for high temp. fluids, has a feed header of titanium or other high temp. metal. The main shell of the exchanger is joined to the feed header by solders or welds which are protected from heat damage by a partition which forms a separate chamber to retain the fluid under conditions of reduced circulation. The partition (or baffle) is made of the same metal as the header and is fixed to the wall. The exchanger is esp. suitable for use in aircraft or space craft where the high speeds result in the cooling fluid, i.e. the external air, being itself at a high temp. Replacement of the aluminium by a high temp. metal in the feed header gives some protection from heat damage which may otherwise occur. Other vulnerable areas, which are the welds, are protected by a partition in the inlet header which retards circulation, thus reducing strain on the welds from press., and a baffle placed between the partition and the exterior wall of the header which reduces the heat transmitted by conduction. The cooling air passes between the tubes, carrying the fluid to be cooled, which have fins to increase the surface area and hence the efficiency.