Effect of Richardson number on transient double diffusive mixed convection: A thermo-hydrodynamic study

Abstract

The goal of the paper is to evaluate the characteristics of the fluid flow, heat, and contaminant transfer in an indoor air environment. A two-dimensional ventilated space having a discrete heat and contaminant source at their mutually perpendicular position is constructed to conduct a numerical study. The governing equations with apprupirate boundary conditions of the model are evaluated by Galerkin weighted residual method. The transport characteristics are discussed for varying Richardson number 0.1 ≤ Ri ≤ 10 and dimension less time 0.1 ≤ τ ≤ 1 by the corresponding stream function, heat function, and mass function. Priority is given to analyzing the necessary factors – dependence on average Nusselt number, average Sherwood number, the average fluid temperature and mass concentration in the enclosure, along with the average temperature of the exit port to visualize the ventilation technique. Numerical output illustrates that – the attributes of the transport particles are largely determined by the interaction of the natural convection of heat and contaminant source with the mechanically forced flow of cool air. Results showed that mixed convection method is a better way to showcase efficient ventilation of the transport particles from the enclosure through a practical yet non-complex approach. This study will be a guide for design consideration for roof-based double-diffusive systems with partial heat and mass generation.

Keywords

• Richardson number
• Double-diffusive
• Mixed convection
• Transient
• Thermo-hydrodynamic