Session: 05-08 Particles for Thermal Storage in CSP 1

Paper Number: 114612

114612 - Modeling Radiative Heat Transfer in Dispersed Particle Flow System Using a Stochastic Approach 

The relative contribution of radiation in the overall heat transfer in a dilute particle flow system (< 0.1 of solid volume fraction) with co- or counterflow air is not well understood. Understanding the multimode heat transfer in this scenario is important in solar thermochemical energy storage systems where small (D < 300 micron), reactive particles fall by gravity and exchange energy with surrounding tubes, while a reacting gas flows in counterflow. Energy is exchanged from the particles to the tubes via convection through the gas and directly by radiation.   To address this challenge, this study focuses on investigating radiation heat transfer process in dilute particle flow heat exchangers using a Monte Carlo method. The method is utilized to predict heat transfer coefficient by random generation of energy ray bundles and tracing its interception by the randomly suspended particles in three dimensions. The particle and surface are treated as black bodies to evaluate the absorption and radiative heat transfer coefficient at different suspension density, optical thickness, and particle size. The results show an increase of radiation absorption from surface-to-particle and an inverse relationship from particles-to-surface with increasing suspension density and optical thickness. The model predicts a strong dependence of radiative heat transfer on suspension density at different temperatures. These results provide a simple analytical expression to quantify radiative heat transfer coefficient for dilute flow particles. Finally, the study gave an insight into the fundamental physics of radiation in disperse flow which can be utilized in optimizing the design of particle based heat exchanger and solar receivers used in concentrated solar power plants.

Presenting Author: Muhammad Umer The Pennsylvania State University

Presenting Author Biography: Muhammad Umer is Fulbright Scholar pursing his PhD in Mechanical Engineering at The Pennsylvania State University.