title: Effect of particle-particle collision in decaying homogeneous and isotropic turbulence.
abstract: The effect of particle-particle collision in decaying homogeneous and isotropic turbulence in the absence of gravity is studied using direct numerical simulation. The objective is to verify the relative importance of the particle-particle collision effect on particle distribution and other characteristics in gas-solid flows with transition from dilute to dense flow. A pseudospectral method coupling with a discrete element method (a hard-sphere approach) is used to simulate the gas turbulence and particle-particle collision dynamics. The effects of particle-particle collisions with different Stokes numbers and mass loadings are investigated. Suggestions for the consideration of the particle-particle collision effect in transition from dilute to dense gas-particle flow are provided. An empirical criterion for demarcation of dilute and dense flow is established. A selective effect of particle-particle collision on particle distribution with particle Stokes numbers higher and lower than unity is found and qualitatively demonstrated.
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, People's Republic of China.
authors.forename: Nan
authors.initials: N
authors.lastname: Gui
authors.forename: JianRen
authors.initials: J
authors.lastname: Fan
authors.forename: Kefa
authors.initials: K
authors.lastname: Cen