Lie group analysis for thermophoretic and radiative augmentation of heat and mass transfer in a Brinkman-Darcy flow over a flat surface with heat generation

A boundary layer analysis is presented to investigate numerically the effects of radiation, thermophoresis and the dimensionless heat generation or absorption on hydromagnetic flow with heat and mass transfer over a flat surface in a porous medium. The boundary layer equations are transformed to non-linear ordinary differential equations using scaling group of transformations and they are solved numerically by using the fourth order Runge-Kutta method with shooting technique for some values of physical parameters. Comparisons with previously published work are performed and the results are found to be in very good agreement. Many results are obtained and a representative set is displayed graphically to illustrate the influence of the various parameters on the dimensionless velocity, temperature and concentration profiles as well as the local skin-friction coefficient, wall heat transfer, particle deposition rate and wall thermophoretic deposition velocity. The results show that the magnetic field induces acceleration of the flow, rather than deceleration （as in classical magnetohydrodynamics （MHD） boundary layer flow） but to reduce temperature and increase concentration of particles in boundary layer. Also, there is a strong dependency of the concentration in the boundary layer on both the Schmidt number and mass transfer parameter.

Steady-state model for predicting size-resolved gas-particle partitioning of semi-volatile organic compounds (SVOCs) in indoor environments

Semi-volatile organic compounds(SVOCs)are ubiquitous and important pollutants in indoor environments.The strong partition between gas phase and suspended particles has significant effects on the transport,human exposure via inhalation,and control strategies of indoor SVOCs.Several models have been developed to simulate the gas–particle partitioning of indoor SVOCs,including a steady-state model by expanding the steady-state model suitable for the outdoor environment to indoor environments.However,the effects of two important indoor environment-specific parameters,i.e.,the particle size distribution(PSD)and the air-change rate(ACH),were not considered in the existing steady-state model,leading to the inaccurate predictions among buildings.To solve this problem,this study developed a novel steady-state model to more comprehensively simulate the gas-particle partitioning of indoor SVOCs by incorporating the effects of PSD and ACH.Better agreement between the predictions of the novel model and the results collected via both field tests and laboratory tests(retrieved from two different studies)supported the effectiveness of the improvements in the novel model.Sensitivity analysis further supported the necessity of involving PSD and ACH.Further implications of the novel model were also discussed.This study should be helpful for deepening the understanding and accurate simulation of the gas-particle partitioning,as well as the transport and human exposure via inhalation,of indoor SVOCs.