One-Dimensional Simulations of Jet Fuel Thermal-Oxidative Degradation and Deposit Formation Within Cylindrical Passages

Abstract

Flowing aviation fuel is used as a coolant in military aircraft. Dissolved O2 reacts with the heated fuel to form undesirable surface deposits which disrupt the normal flow. For purposes of aircraft design, it is important to understand and predict jet fuel oxidation and the resulting surface deposition. Detailed multi-dimensional numerical simulations are useful in understanding interactions between the fluid dynamics and fuel chemistry. Unfortunately, the detailed simulation of an entire fuel system is impractical. One-dimensional and lumped parameter models of fluid dynamics and chemistry can provide the simultaneous simulation of all components which comprise a complex fuel system. In this work, a simplified one-dimensional model of jet fuel oxidation and surface deposition within cylindrical passages is developed. Both global and pseudo-detailed chemical kinetic mechanisms are used to model fuel oxidation, while a global chemistry model alone is used to model surface deposition. Dissolved O2 concentration profiles and surface deposition rates are calculated for nearly isothermal and nonisothermal flow conditions. Flowing experiments are performed using straight-run jet fuels, and the predicted dissolved O2 concentrations and surface deposition rates agree reasonably well with measurements over a wide range of temperature and flow conditions. The new model is computationally inexpensive and represents a practical alternative to detailed multi-dimensional calculations of the flow in cylindrical passages. [S0195-0738(00)01204-8]