Investigation of two advanced cooling mixing concepts for a rich quench lean combustor.

Abstract

To support the development of a rich quench lean pilot zone for a staged aeroengine combustor, two rectangular rich quench lean (RQL) combustor sectors have been investigated under atmospheric conditions. Two advanced cooling mixing concepts, effusion and impingement cooling with one and two rows of secondary air inlet holes in the mixing zone have been measured using intrusive and nonintrusive measurement techniques. The results elucidate the interrelations between the cooling concepts and the respective mixing and emissions performances. The measurements were accompanied by numerical calculations supporting the interpretation of the measured data. Drawbacks were observed for the near stoichiometric conditions of the effusion cooling concept near the wall, however the quench zone design with two rows of staggered holes performs well. On the contrary the impingement cooling system shows good results for the homogeneity of the primary zone, but since less quench air is available with impingement cooling, optimum mixing is more difficult to achieve.