When Flows Turn Turbulent in the Supercritical Fluid Region

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From concentrated solar power plants to rocket engines, energy conversion systems are continually re-engineered to perform ever better. Often this involves fluids being pushed into the supercritical region, where highly non-ideal thermodynamic effects are at play. Yet, our fundamental understanding of flow physics at such conditions lags behind to successfully realize these exciting engineering applications. Especially, the sharp variations in thermophysical properties and the high optical density at supercritical pressures lead to significantly richer flow physics and even more intricate phenomena in turbulence. In three work packages, I will (1) elucidate laminar-turbulent transition; (2) unravel compressible effects on turbulence; and (3) unveil turbulence-radiation interactions, ranging from the critical point to conditions far into the supercritical region of a fluid. Exploiting my recent achievements, I will perform the first study of its kind, combining advanced hydrodynamic stability analysis, novel multi-physics simulation tools, and original experiments with infrared thermography to identify and characterize new flow physics in the supercritical fluid region. The results will reveal how and when flows in the non-ideal region transition to turbulence, how strong compressibility affects turbulent heat transfer, and how the higher optical density of a fluid interacts with turbulence. Uncovering these mechanisms will actively contribute to a breakthrough in a wide range of emerging technologies, from utility-scale concentrated solar power plants to more powerful and efficient propulsion systems.