Pre-Swirled Cooling Air Delivery System Performance

Abstract

This paper reports results from numerical simulations of the flow in pre-swirl cooling air delivery systems. Two different systems have been investigated corresponding to experimental rigs for which measured data is available. The rigs are representative of aero-engine conditions. The difference in the performance of the two rigs has been addressed. The flow in the pre-swirl nozzles and in the pre-swirl chambers has been investigated separately. For the pre-swirl chamber a simplified model, in which the nozzle is replaced by a slot, has been used to reduce the computational effort required. Nevertheless numerical results are in good agreement with experimental measurements. It is shown that the difference in the geometry of the pre-swirl chambers is largely responsible for the difference in performance of the rigs. Numerical results have also been compared with predictions from a previously published simplified model. An adjustment of the empirical constants in the simple model has been proposed in order to improve the prediction of the moments in the pre-swirl chamber.