Advances in Numerical Simulation of Pulsating Combustion at ENEL

Abstract

Abstract This paper concerns the simulation of unsteady combustion processes. It gathers up-to-date results of simulation activities, part of a long-term research program between the Italian National Institute for Electric Power (ENEL) and the University of Padova. The software used is ‘Fluent’1; the hardware a Vax 8530 and a Cray X-MP/14. The paper is divided in two major sections: one dealing with combustion instabilities, the second with pulse combustion. In the first section, of the several known forms of combustion instabilities, our attention is directed toward the investigation of one caused by fluctuations in turbulent mixing rate. Assuming that the combustion rate is controlled by mixing of the chemical species (and not by chemical kinetics), we show that the fluctuations of velocity which accompany acoustic waves produce fluctuations in turbulence and then fluctuations in reaction rate. We also show that mean flow plays a key role in determining the sign of these fluctuations and therefore the o...