Experimental Optimization of Rolls-Royce AE3007 Sump Design

The original sump design of Rolls-Royce AE3007 central sump is a tangential sump. An experimental program at Purdue University was conducted to investigate the characteristics of a tangential sump design. The research employed a bespoke experimental rig consisting of modular transparent chamber to allow unprecedented view of the two-phase flow inside the bearing chamber. It was found that a persistent liquid pooling near the drain entrance of a tangential sump obstructs the outflow to the scavenge off-take. While space requirement is minimal, the scavenge performance of a tangential sump is poor. A prototype advanced sump was proposed and built with features to address various issues found in the tangential sump. In this paper, further experimental work on the refinements of the advanced sump is presented. This includes experimental study on the effect of a fence and splitter plate, off-take hole diameter and its location, the effect of gravity by tilting, upstream wall fairing, as well as the depth of the sump itself. The experiments showed that the faired upstream wall modification can reduce residence volume significantly across different operating conditions, indicating improvement in scavenge performance. The other modifications help to reduce residence volume only in certain operating conditions. The results of this study helped towards the birth of an optimized sump design, known as Indy sump. The Indy sump has been accepted as a superior sump design and has been used as a benchmark in many sump design studies.