Quasi-steady-state evaporation model for real multi-component fuel droplets

The ongoing movement to replace the NATO military aircraft fuel, F34 (JP-4) with F40 (JP-8), a kerosene-type fuel almost identical to JET A1, has prom pted new research on the effects of fuel properties. The physics and the ch emistry occurring during the vaporization and burning process is complex, m aking it necessary to split the problem into distinct phenomenological mode ls such as the prediction of the rate of vaporization from real fuel blends . The objective of this study was to develop an algorithm for multi-compone nt droplet vaporization and to incorporate it into a complete spray combust ion analysis for engineering applications. The work described relates the r ate of evaporation and the history of the multi-component fuel droplets, JP -4 and JET A1, in an infinite surrounding medium of air moving at low veloc ity so that the flow is considered laminar. Computational Fluid Dynamics co des (CFD) are currently used to define appropriate design strategies for co mbustion chamber modelling. The integration of the new multi-component fuel evaporation model that accounts for fuel specification evolution during th e evaporation process into existing CFD codes leads to improved predictions of droplet evaporation. This is shown to be particularly important in calc ulations made under cold-starting conditions in gas-turbine engines.