Session: Student Poster Competition

Submission Number: 186995

Nusselt Correlations for Microchannel Molten Salt Co2 Stairstep Heat Exchangers in Real Gas Conditions 

Molten salt to sCO₂ heat exchangers are important components in next-generation energy systems, particularly in applications involving thermal energy storage and advanced power cycles. Stairstep microchannel heat exchanger designs, which utilize square channels for both fluids, offer a compact and efficient solution but require accurate thermal modeling to support design and optimization. While computational fluid dynamics (CFD) provides high-fidelity results, it is computationally expensive and often impractical for large design sweeps, making reduced-order models an attractive alternative. These reduced-order models depend heavily on the use of reliable Nusselt correlations. Although square microchannel correlations are available in the literature, their applicability to molten salt–sCO₂ systems is not well established, particularly when operating outside of their original validation ranges. In this work, the molten salt side operates below portions of the Reynolds number range, while the sCO₂ side falls below parts of the Prandtl number range and exhibits significant property variation. This study evaluates several candidate correlations by comparing reduced-order model predictions with ANSYS Fluent results across varying hydraulic diameters and mass flow rates. The goal is to assess which correlations remain reliable under these conditions and to determine whether reduced-order modeling can be used effectively for heat exchanger design and early-stage optimization without relying exclusively on CFD.

Presenting Author: Noah Santiago-Walsh University of Central Florida (CATER)

Presenting Author Biography: Sophomore Undergraduate at UCF

Authors:

Noah Santiago-Walsh University of Central Florida (CATER)
Abhilash Prashad University of Central Florida (CATER)
Shinjan Ghosh University of Central Florida(CATER)
Erik Fernandez University of Central Florida (CATER)
Marcel Otto University of Central Florida (CATER)
Jayanta Kapat University of Central Florida(CATER)