Thermal stability and degradation of a commercial jet fuel were studied using an experimental rig developed recently. The apparatus consists of a fuel pre-heating section to simulate the usage of fuel as a coolant on aircraft, and a test section to simulate operating conditions found in aircraft injector fuel nozzles. Two independent diagnostic techniques, pressure drop measurements and carbon burn-off, were applied to assess carbon deposition produced within a test section. Parametric studies were performed to investigate the effect of test section inner diameter, test section material, and test section inlet temperature gradient on carbon deposition within the test section. It was determined that as the inner diameter of a test section increased, carbon deposition generally decreased. The axial location of maximum surface deposition moved downstream in a narrower test section. It was also found that solid carbon deposition decreased by increasing the test section inlet temperature gradient.

Various aspects of the thermal stability problem associated with the use of broadened-specification and nonpetroleum-derived turbine fuels are addressed. The state of the art is reviewed and the status of the research being conducted at various laboratories is presented. Discussions among representatives from universities, refineries, engine and airframe manufacturers, airlines, the Government, and others are presented along with conclusions and both broad and specific recommendations for future stability research and development. It is concluded that significant additional effort is required to cope with the fuel stability problems which will be associated with the potentially poorer quality fuels of the future such as broadened specification petroleum fuels or fuels produced from synthetic sources.

For technical readers in the aviation and fuel industries, and in testing laboratories, explores the history and philosophy of the thermal stability of aviation fuel, and considerations during the fuel's manufacture, storage and transport, use, and assessment. The 13 papers, representing a number of

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