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The altitude-ignition limits of a condenser-discharge ignition system installed on a turbojet engine were determined at a flight Mach number of 0.6 using 1.1-pound Reid vapor pressure fuel. Ignition was possible up to an altitude of 55,000 feet with 4.8 joules per spark and 6 sparks per second.

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In heat exchangers, in which the walls are heated by intemal heat sources, it is possible for wall temperatures greater than the mean to occur in the corners of noncircular flow Passages. Thus in a square or triangular passage low velocities occur in the corners, and the resulting decrease in the heat transfer coefficient produces higher temperatures in the walls at these locations. A generalized analysis is presented taking into account the variation in the heat transfer coefficient along the surface, by which it is possible to compute local temperatures in the walls of noncircular flow passages in the vicinity of the corners. Computations have been made for a representative component composed of a honey comb of rectangular passages. The resulting temperature at the hottest point is approximately 125 deg F greater than the unifomn plate temperature. This analysis is based on a 90 deg angle between the plate and retaining plate, and a uniforn source distribution throughout all plates. Had the angle between the primary plate and retaining plate been much less than 90 deg on both sides, then the resulting local temperature rise would be several times the above value. If the primary plate and retaining plate are …

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