Compact air-to-air heat exchanger for jet engine application

Claim 1

A compact air-to-air heat exchanger, adapted for use in a gas turbine engine of the fan bypass type having a hot flow of cooling air, a cool flow of fan air, and a primary fan air stream duct in which a first portion of said cool flow of fan air flows, comprising: a. means for cooling said hot flow of cooling air; b. and, means for heating a second portion of said cool flow of fan air, with this said means in association with said cooling air cooling means; wherein said compact air-to-air heat exchanger is disposed internal of said bypass type gas turbine engine, whereby heat is transferred from said hot flow of cooling air to said second portion of said cool flow of fan air, thereby resulting in an exhaust flow of cooled cooling air; and wherein said means for cooling and said means for heating include, in common, a secondary fan air stream duct, adjacent to said primary air stream duct, through which flows said second portion of said cool flow of fan air, and, a plurality of flow tubes through which flows said hot cooling air, with said flow tubes disposed within and in transverse relationship to said secondary fan air stream duct, and are also simultaneously disposed in cross flow relationship with and to said second portion of said cool flow of fan air, and with said flow tubes having a plurality of circumferentially spaced, radially extending headers which are supported from and are connected to a common cooling air inlet manifold disposed radially inward therefrom and a plurality of circumferentially spaced, radially extending headers which are supported from and are connected to a common cooling air outlet manifold disposed radially inward therefrom.