Effects of particle velocity fluctuations on inter-phase heat transfer in gas-solid flows. (12th October 2019)

• Record Type: Journal Article
• Authors: Huang, Zheqing; Zhang, Chi; Jiang, Ming; Wang, Huizhi; Zhou, Qiang
• Is Part Of: Chemical engineering science. Volume 206(2019)
• Page Start: 375
• Page End: 386
• Publication Date: 2019-10-12
• Subjects: Direct numerical simulations -- Granular temperature -- Heat transfer -- Nusselt number; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2019.05.047
• Languages: English
• ISSNs: 0009-2509

Abstract

Graphical abstract: Highlights: Effect of particle velocity fluctuation on the heat transfer in gas-solid flows is investigated via an IBM-LBM. Nusselt number increases with increasing granular temperature-based Reynolds number. Nusselt numbers on individual particles follow the Log-Normal distribution. Abstract: Heat transfer in gas-solid flows has been numerically investigated via an immersed boundary-thermal lattice Boltzmann method. Stationary random assemblies of spheres are adopted in the simulations. The effect of particle velocity fluctuations whose magnitude is represented by the so-called granular temperature is accounted for by implementing velocity fluctuations obeying the isotropic Maxwellian distribution on spheres. It is found that particle fluctuations enhance the heat transfer between the gas and solid phases. This enhancement increases with increasing granular temperature-based Reynolds number and becomes less significant as the particle Reynolds number and the solid volume fraction increase. It is also found that the Nusselt numbers on individual particles follow the Log-Normal distribution at both zero and finite granular temperature conditions. The long tail of this distribution is caused by the existence of a non-negligible portion of the domain with fast local gas velocities that could significantly promote heat transfer.