Emergency power unit

Claim 1

A combustor for an emergency power unit for aircraft, comprising: a thermal liner defining a combustion chamber having openings at opposite ends thereof; a pressure shell enclosing said thermal liner; an insulator disposed between said thermal liner and said pressure shell, said insulator allowing said thermal liner to obtain a temperature approximating the combustion temperature, while inhibiting heat transfer to said pressure shell whereby said shell operates at a greatly reduced temperature; means for initiating the combustion process within said combustion chamber; and an injection head secured to said thermal liner in an arrangement sealing one of said openings of said combustion chamber, said injection head configured and arranged to deliver oxidant and fuel to said combustion chamber, means for receiving pressurized air attached to said injection head; means for receiving aviation fuel attached to said injection head; first air plenum disposed radially around said means for receiving aviation fuel and in open communication with said means for receiving pressurized air such that said first air plenum distributes said pressurized air radially around said means for receiving aviation fuel; a second air plenum disposed radially around said means for receiving aviation fuel in series with said first air plenum; a plurality of air flow passages between said first air plenum and said second air plenum; a second plurality of air flow passages extending through said injection head between said second air plenum and said combustion chamber; and an aviation fuel passageway extending from said means for receiving aviation fuel to said combustion chamber.