An Experimental Investigation on Flow Field in a Dump Combustor Model.(Dept.M)

Abstract

The flow field characteristics in a dump combustor model is investigated experimentally. In this paper. The model consists of a square cross-section area duct with a sudden enlargement chamber followed by a convergent nozzle. Attention is focused on finding the effect of nozzle existence4 at the end of the chamber, the chamber length, and the Renold's number ( based on the step height and inlet maximum velocity ) on the wall pressure distribution, the axial centerline velocity and pressure, the velocity profiles, the recirculation zone size and the reattachment length. The results are compared with the corresponding results when the nozzle is absent. The results indicate that the reattachment length, the recirculation zone, and the redevelopment after reattachment is almost the same in the case without nozzle and when chamber length is 8.65 step height with nozzle existence. The wall pressure exhibits a substantial increase just before the nozzle, entrance, while it continues its decrease, in the case without nozzle, because of viscous friction. The results show also that the redevelopment zone following the reattachment shrinks as the chamber length decrease. The reattachment occurs inside the nozzle when the chamber length becomes 4.65 step height. The change in Reynold's number shows a small effect on the wall pressure distribution.