Unified gas-kinetic wave-particle method for gas-particle two phase flow from dilute to dense solid-particle limit

TL;DR

This paper introduces a unified computational framework combining gas-kinetic and wave-particle methods to simulate gas-particle flows across all solid concentration regimes, from dilute to dense.

Contribution

The paper presents a novel integrated method that seamlessly models gas-particle flows across different regimes using coupled solvers and adaptive wave-particle decomposition based on local Knudsen number.

Findings

Validated accuracy through typical gas-particle problem simulations

Improved modeling of drag force and inter-particle friction at various concentrations

Effectively captures non-equilibrium transport in dilute regimes

Abstract

In this paper, a unified framework for particulate two-phase flow will be presented with a wide range of solid-particle concentration from dilute to dense limit. The two phase flow is simulated by two coupled flow solvers, i.e., the gas-kinetic scheme (GKS) for the gas phase and unified gas-kinetic wave-particle method (UGKWP) for the particle phase. The GKS is a second-order Navier-Stokes flow solver for the continuum flow. The UGKWP is a multiscale method for all flow regimes. The wave and particle decomposition in UGKWP depends on the cell's Knudsen number (Kn). At a small Kn number, the high concentrated solid particle phase will be modeled by the Eulerian hydrodynamic wave due to the intensive particle-particle collisions. At a large Kn number, the dilute solid particle will be sampled and followed by the Lagrangian particle formulation to capture the non-equilibrium transport. In the transition regime, the distribution and evolution of particle and wave in UGKWP are controlled by the local Kn number with a smooth transition between the above limits. In the current scheme, the two phase model improves the previous one in all following aspects: drag force model for different solid particle concentrations; the frictional pressure in inter-particle contacts at high solid-particle concentration; a flux limiting model to avoid solid particles' over-packing; additional non-conservative nozzle and work terms for the gas phase. Besides, the inter-particle collisions have been refined numerically for the dense particle flow through the discretization of the collision term and numerical flux function. The numerical scheme is tested in a series of typical gas-particle problems. The results validate the accuracy and reliability of the proposed method for gas-particle flow.