Thermal Cracking of Hydrocarbon Aviation Fuels in Regenerative Cooling Microchannels

Regenerative cooling with hydrocarbon aviation fuels on board is taken as a promising technology for the thermal management system of next-generation aircraft. An improved methodology of an electrically heated tube (1 mm i.d.), i.e., applying the variable reactor tube length to carry on thermal cracking of supercritical hydrocarbon aviation fuels as the electric current heating maintains constant, was proposed to experimentally obtain detailed information on the local concentration and temperature along the microchannels of a heat exchanger. For the first time a series of experimental data on detailed local chemical compositions of cracked hydrocarbon fuel along the cooling microchannels were reported under supercritical conditions (5 MPa, 680-700 degrees C), and the calculated thermodynamic properties, velocity, and residence times along the tube were also reported. A modified molecular reaction model consisting of 18 species and 24 reactions was developed to predict thermal cracking of hydrocarbon aviation fuels in a wide range of cracking conversion (up to 86%). The work is significant for the design of regenerative cooling structures in predicting the local chemical compositions, estimating thermophysical properties, and coking of the cracked hydrocarbon fuels for heat transfer analysis.