Session: 07-01: Experimental Characterization of Particle Flows

Paper Number: 170051

170051 - Measurement, Understanding, and In-Situ Diagnostics of Thermal Transport in Moving Particles Using Modulated Photothermal Radiometry 

Abstract: 

Ceramic particles are promising heat transfer media for next-generation concentrating solar power (CSP) systems. However, heat transfer in moving particle flows remains a critical challenge that impacts the performance and cost of moving particle heat exchangers. Characterizing thermal transport under high-temperature and dynamic conditions is particularly difficult. Moreover, enabling in-situ diagnostic capabilities for such systems is highly desirable.

In this work, we present recent advances in a non-contact, high-temperature thermal characterization technique known as modulated photothermal radiometry (MPR). This frequency-domain method enables accurate thermal conductivity measurements of granular media in both static and flowing states at elevated temperatures.

Our MPR measurements reveal that thermal transport in moving ceramic particles is significantly altered compared to static conditions. The frequency-resolved nature of the technique allows for the separation of near-wall thermal resistance and bulk particle-bed thermal resistance, both of which are shown to be flow-velocity-dependent. These insights are further used to theoretically study their implications on the overall heat transfer coefficient in moving particle bed heat exchangers.

Finally, we demonstrate the use of MPR for in-situ and operando diagnostics in a prototype moving particle heat exchanger, highlighting its potential for real-time thermal monitoring in CSP systems.

Presenting Author: Renkun Chen UC San Diego

Presenting Author Biography: Renkun Chen is a Professor in the Department of Mechanical and Aerospace Engineering at the University of California San Diego. He received his Ph.D. in Mechanical Engineering from UC Berkeley in 2008 and has been a faculty member at UC San Diego since 2009. His research group focuses on probing fundamental heat transfer at the micro- and nanoscale, as well as developing materials and devices for thermal energy conversion, storage, and management.