Investigation of the Flow Characteristics in a Sink-Swirl Flow within Two Disks

Abstract

Flow characteristics in a sink-swirl flow within two disks are examined experimentally and numerically. The experiments and the predictions have been carried out for three bulk Reynolds numbers and four contraction ratios. Results show that as the contraction ratio and the Reynolds number increase, the pressure coefficient increases. Stronger vortices will be produced resulting in a higher tangential velocity and hence a higher pressure drop. The radial pressure decreases slowly from the inlet periphery up to halfway along the disk and then decreases sharply as the flow approach the exit hole. Air enters through the peripheral gap between the two disks and converges to the center where it discharges axially through the exit hole. This indicates that the flow moved towards a more favorable pressure gradient, hence the vortex flow accelerated according to the angular momentum conservation. It can be seen that the Reynolds stress model gives good agreement with the present experimental data and the percentage difference error between the predicted and experiments is less than 10%.