In diesel engines, fuel is injected into hot air and self-ignited without any air/fuel premixing. Combustion in diesel engines is particularly complicated as it occurs under turbulent and nonpremixed conditions. The propagation of flames in such an environment can be modelled using the "triple flame" concept where it is assumed that the flame structure propagates following a surface of stoichiometric mixture.
The objectives of the project are to investigate elementary flame structures for partially premixed combustion from basic principles and to integrate the results into a flamelet library for turbulent combustion.
The role of the coordinator (RWTH Aachen) consists in developing the flamelet concept for partially premixed turbulent combustion and in providing a flamelet library of triple flamelets.
Large-Eddy-Simulations will be applied (U. Karlsruhe) to investigate the structure of partial premixed combustion. The task of U. Napoli will consist in identifying the parameters which can influence triple flame structures and will provide information indicating the temporal statistics and spatial fluid-dynamic structures for which triple flame can be exploited. The contribution of U. Bristol will be to broaden the current concept of laminar triple-flamelets by including flow properties representative of combined stretched vortices and triple flamelet structures of real turbulent partially premixed combustion. Both theoretical and numerical simulations will be used. The Cambridge group will provide experimental benchmark data of triple flame speed, length and width as a function of the fuel concentration gradient and will advise the other partners on suitable boundary conditions. At the U. of Madrid, analysis of the triple flame structure will be generalize to more general kinetic schemes. The four-step kinetic mechanism for methane, found to describe properly the flame dynamics of many typical hydrocarbons, will be evaluated.
Funding SchemeCSC - Cost-sharing contracts
BS8 1TW Bristol, Clifton
CB2 1PZ Cambridge