Towards boiling Taylor-Couette turbulence

Abstract

Taylor-Couette (TC) flow is the flow in-between two concentric cylinders which rotate independently. It is together with Rayleigh-Benard (RB) convection, the flow in-between two plates, heated from below and cooled from above, one of the canonical flows where turbulence can be probed and put to the test. As compared to RB flow, where the flow is thermally-driven, the driving in TC flow is purely mechanical which is far more efficient when designing experiments. In this thesis, we focus our investigation towards a better understanding on the effect of vapor bubbles in high-Reynolds TC flow. These bubbles are the product of boiling a low-boiling point liquid which we use as the working fluid. We have designed an experiment, where the boiling can be well-controlled and monitored in order to quantify the physical response of the flow due to the bubbles, in particular its drag. We find that vapor bubbles are just as efficient in reducing the drag in the flow as air bubbles. Almost 50% drag reduction can be achieved when the volume fraction of the bubbles is ~8% , the Taylor number is ~10^12 and the Weber number is We>1.