A preliminary study of ram-actuated cooling systems for supersonic aircraft

Stalder, Jackson R., Wadleigh, Kenneth R.

An analysis has been made of the characteristics of several cooling cycles suitable for cockpit cooling of supersonic aircraft. All the cycles considered utilize the difference between dynamic and ambient static pressure to actuate the cooling sysem and require no additional power source. The results of the study indicate that as flight speeds become greater, increasingly complex systems are required to reduce the ventilating air to tolerable temperatures. At altitudes above approximately 35,000 feet, a system composed of an externally loaded expansion turbine in conjunction with a supersonic diffuser would maintain tolerable ventilating air temperatures, at least up to a flight Mach number of 2. The most complex system considered, composed of a compressor, intercooler, and expansion turbine with the intercooler cooling air decreased in temperature by expansion through an auxiliary turbine is capable of maintaining a ventilating air temperature less than ambient temperature up to a flight Mach number of 3.7. The preceding results for both systems are predicated on a cockpit pressure equal to ambient static pressure. It is possible that similar systems can be devised which will allow operation of ram-actuated cooling cycles with the cockpit pressurized, with, however, added system components required in the form of additional heat exchangers and turbines.

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