New cryogenic nitrogen facility for Rayleigh-Bénard convection at high Rayleigh number - Part 1: Facility Design and Capabilities*

Multiple theories predict the existence of an ultimate regime of heat transfer for Rayleigh-Bénard convection (RBC), yet the experimental evidence supporting the transition to this regime has been contradictory. The study of RBC under rotation, specifically at underexplored geophysical-scale Rayleigh numbers, is of particular interest. We present a newly developed, multi-functional facility for studying both RBC at high Rayleigh numbers, and rotating RBC. This novel facility uses cryogenic nitrogen near the gas-liquid coexistence curve from atmospheric pressure up to its critical point as the working fluid. Interchangeable sidewalls permit studying RBC in test cells of various aspect ratios, and optical access allows for application of optical diagnostic techniques such as PIV. The facility is designed to exceed Rayleigh numbers of 10¹⁵ for a test cell of aspect ratio 1, and 10¹⁷ for a test cell of aspect ratio 0.2. We present its salient features in this talk.