Gravitational Effect Formulation on In-House Air-Particle Flow Solver

Abstract

Conventional efforts on the design of air-particle related environments are merely on heuristic and experience basis. Distribution control of particles in air such as dust, soot, smoke, chemical aerosol or any other pollutants are only simulated in current years when computational power is slowly fading from being an issue. Most commercial engineering software already equipped with the features but in-house solvers are always developed by institutions of related fields in order to fulfil their research needs. This work is preformed specifically to analyse the effect of additional gravitational effect feature in our newly developed in-house fluid-particle software. The effect is included in the Eulerian-Lagrangian solver so that it capable of simulating heavy particles in environmental air flows. Flow distributions of heavy particles such as liquid aerosol, sand or granular fertilizer are greatly affected by gravitational effect as compared to relatively buoyant particles such as smoke and light dust. Transient particle distribution in a ventilated room is simulated in this work. 10,000 particles that represent homogenous 2 mm Hemlock wood dust were randomly distributed in 3.3x2.8x5.9 m3 ventilated room that consist of two ceiling air intake and four bottom wall ventilation outlets. Homogeneous Hemlock wood solid sphere particles with diameter of 2 mm is simulated while the air intake is equivalent to 0.0944 m3/s. Simulation without the particle gravitational effect shows physically irrational results where 26 % of particles stayed at the top half of the room. Simulation with particle gravitational effect shows otherwise where 92 % of the particles settled at the bottom half of the room when measures at the same transient duration. This finding agrees well with distribution patters of previous experiments and simulation works. The introduction of gravitational effect in the newly developed in-house air-particle solver can be considered as the turning point where simulations of environmental air-particle related studies such as dust ventilation, aerosol control or even granular fertilizer distributions out of boom sprayer are possible.