Direct contact liquid heater and heating method

A direct contact water heater for heating water by the hot exhaust gases from a torpedo propulsion engine comprising, an elongate exhaust housing having an inlet connectable to the exhaust gas discharge of the torpedo propulsion engine and an outlet for ocean discharge, a mixing chamber intermediate the ends of the exhaust housing having a tubular wall, means for imparting a swirl velocity to exhaust gases entering said exhaust housing whereby swirling exhaust gases enter said mixing chamber, means for injecting water into said swirling exhaust gases immediately ahead of said mixing chamber to form water droplets which are centrifuged toward said wall of the mixing chamber to form a liquid annulus which moves along the length of the mixing chamber with the bulk of the swirling exhaust gases flowing centrally of the mixing chamber and inside the liquid annulus toward the exhaust housing outlet, and means at the end of the mixing chamber for collecting water from the liquid annulus and discharging the water from the water heater comprising a tubular pump housing rotatably mounted at an end of the exhaust housing and having a wall forming a continuation of the mixing chamber wall to receive the liquid annulus, means carried by the pump housing for rotating the pump housing in response to the flow of exhaust gases, and a pitot pump probe having an inlet position adjacent the pump housing wall to receive water from the liquid annulus.