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Engine cooling by nucleate boiling requires a profound knowledge of cooling systems components: heat exchangers, water pumps, eventually liquid-vapor separators, on the part of equipment manufacturers. Experimental and theoretical studies of the principal heat exchanger, I.E., the vapor-condensor, were effected. The experimental phase required the development, after careful study, of a test set-ups specifically designed for vapor-condensors. Tests are conducted under controlled intake pressures and temperatures, and sub-cooled outlet conditions. Under varying air-flows, outlet-liquid measurements yield instructive information relative to exchanger thermic performance. The influence on performance of tube shape, direction of liquid circulation (horizontal or vertical) and number of passes was also studied. Concurrently, thermic visualization by infra-red camera permits qualitative evaluation of vapor distribution within the condenser.

A fundamental vehicle study for a new engine cooling system, the so called NUCLEATE BOILING ENGINE COOLING SYSTEM, has been tested under real and critical conditions in a climate controlled wind-tunnel. Using this cooling system requires a profound knowledge of the cooling circuit and all cooling components such as: condenser, waterpump, liquid/vapor-separator, expansion tank, fan control unit. After preliminary experimental and theoretical studies, two types of cooling circuits were realized and tested in a car: Completely filled nucleate boiling cooling system Partially filled nucleate boiling cooling system Both types of circuits were sealed systems. This meant there was no evaporation or loss of liquid into the environment. By using the nucleate boiling cooling system, the heat of the cylinder head was dissipated while the boiling process change of liquid phase to vapor at constant boiling temperature.