Heat Transfer Unit Evaluates Performance of Jet Fuels for Supersonic Aircraft

Fuel used as a coolant in the supersonic transport can degrade thermally and affect heat transfer surfaces. A heat transfer unit developed by Esso Research to follow the course of degradation reactions and to relate deposit formation to heat transfer rates has been used under a Federal Aviation Agency program to study fuels varying widely in quality. Data reveal that oxygen disappearance, peroxide buildup, and deposit formation are interrelated and can be roughly correlated with fuel composition. Deposit formation above a certain level generally results in loss in heat transfer; but in some cases increases in heat transfer have been observed. The temperature at which significant deposit buildup takes place and loss in heat transfer occurs in the HTU can be predicted by the fuel “breakpoint” measurement made in the ASTM-CRC Fuel Cokers.