Particle-to-fluid heat transfer in particle-laden turbulence

TL;DR

This paper investigates how inertial particle concentration affects heat transfer in turbulent flows, identifying key parameters and proposing a simplified model based on direct numerical simulations.

Contribution

It identifies the dominant dimensionless parameters affecting heat transfer and introduces a reduced order algebraic model for particle-to-fluid heat exchange.

Findings

Particle Stokes number and heat mixing parameter are most influential.

Momentum two-way coupling has minimal effect on heat transfer.

Proposed algebraic model accurately predicts heat transfer in simulations.

Abstract

Preferential concentration of inertial particles by turbulence is a well recognized phenomenon. This study investigates how this phenomenon impacts the mean heat transfer between the fluid phase and the particle phase. Using direct numerical simulations of homogeneous and isotropic turbulent flows coupled with Lagrangian point particle tracking, we explore this phenomenon over wide range of input parameters. Among the nine independent dimensionless numbers defining this problem, we show that particle Stokes number, defined based on large eddy time, and a new identified number called heat mixing parameter have the most significant effect on particle to gas heat transfer, while variation in other non-dimensional numbers can be ignored. An investigation of regimes with significant particle mass loading, suggests that the mean heat transfer from particles to gas is hardly affected by momentum two-way coupling. Using our numerical results we propose an algebraic reduced order model for heat transfer in particle-laden turbulence.