Development of Advanced Instrumentation and Novel Heat Exchanger Geometries for Molten Salt Environments

Abstract

Elevated temperatures and corrosive environments, typical of molten salt reactor’s operating conditions, may pose challenges to the functionality of instrumentation, sensors and key com-ponents of the cycle. Experimental measurements of fundamental thermal-hydraulic parameters are paramount to advance the knowledge and understanding of the behavior of molten salts, and are necessary for the validation of system-level and computational fluid dynamics (CFD) codes. Experimental testing stations have been utilized to characterize thermal-hydraulic parameters of typical molten salts under steady-state and transient, forced flow conditions, by employing innovative measurement techniques. The use of non-intrusive ultrasound technology for flow rate measurements, pressure loss using state-of-the-art differential pressure transducers, and optical fiber distributed temperature sensors and thermocouple probes have been employed for high-fidelity measurements at elevated temperatures (up to 700 °C). In addition, the development of Printed Circuit Heat Exchangers (PCHE), a potential candidate to Concentrating Solar Power (CSP) and Molten Salt Fast Reactor (MSFR) technologies, was aided by the development of these novel instrumentation techniques in molten salt testing environments. The airfoil-fin micro-channel PCHE, known for its enhanced heat transfer and low pressure drop characteristics, has been assessed in this study. To enable design and application of the airfoil-fin PCHE in energy generation applications, this research campaign aims to assess the effect of the airfoil-fin geometrical arrangement parameters on the overall performance of this PCHE, and sub-sequent development of friction factor and Nusselt number correlations. The optimization study is conducted using prototypical experimental platforms in combination with the development of a CFD based numerical framework, where the experiments are used as a validation criteria. The optimization study is refined by integrating the numerical simulations with Heuristic optimization algorithms, which have aided PCHE design space exploration.