Numerical investigation on the effect of radial location of sealing air inlet and its geometry on the sealing performance of a stator-well cavity

Abstract

This paper investigates the mainstream hot gas ingestion into a new stator-well cavity which consists of upstream and downstream rim cavities as well as a pre-swirl cavity. The effects of the radial location of sealing air inlet hole and the shape of sealing air supply geometry on the flow characteristics and sealing performance of the stator-well cavity have been investigated. Computations are performed for three radius ratios of sealing air inlet-to-rim seal periphery of 0.883, 0.909 and 0.935 and three sealing air supply geometries in terms of hole design and slot design with two height-to-width ratios of 12 and 21. The results indicate that both the radial location of sealing air inlet hole and the shape of sealing air supply geometry has a significant effect on the flow characteristics and sealing performance in the upstream rim cavity, while it negligibly affects the flow structure and sealing effectiveness in the downstream rim cavity. For upstream rim cavity, it is more effective to protect upper walls for the inlet hole at a higher radius, and the sealing effectiveness on inner walls is higher for the inlet hole at a lower radius. Additionally, the slot design shows a lower sealing effectiveness on upper walls than that of the hole design, and with an increase in height-to-width ratio it further decreases. However, the slot design is of benefit to the protection of inner walls as well as the performance of pre-swirl cavity, and as height-to-width ratio increases the sealing effectiveness on inner walls increases.