Articles written in Sadhana
Volume 43 Issue 4 April 2018 Article ID 0064
In this paper, the effect of surface radiation in a square cavity containing an absorbing, emitting and scattering medium with four heated boundaries is investigated, numerically. Lattice Boltzmann method (LBM) is used to solve the energy equation of a transient conduction–radiation heat transfer problem and the radiative heat transfer equation is solved using finite-volume method (FVM). In this work, two different heat flux boundary conditions are considered for the east wall: a uniform and a sinusoidally varying heat flux profile. The results show that as the value of conduction–radiation decreases, the dimensionless temperature in the medium increases. Also, it is clarified that, for an arbitrary value of the conduction–radiation parameter, the temperature decreases with decreasing scattering albedo. It is observed that when the boundaries reflect more, a higher temperature is achieved in the medium and on boundaries.
Volume 45 All articles Published: 18 November 2020 Article ID 0283
In this paper, the effects of channel roughness on the droplet removal efficiency and pressure drop in a zigzag mist eliminator are investigated. The fluid flow, droplet dispersion and deposition through the demister are modelled using a commercial Computational Fluid Dynamics (CFD) tool. The turbulent airflow issimulated using two different Shear-stress Transport (SST) k-w model and Reynolds Stress Model (RSM) with enhanced wall treatment. The Eddy Interaction Model (EIM) is also used to predict the trajectories of thedroplets in the gas flow. The results show that inserting roughness increases the maximum velocity of the gas flow at the bends and enhances the removal efficiency with a little cost of an increase in the pressure drop foreach bend. At the velocity inlet of 2 m/s with 6 lm droplets, the pressure drop and removal efficiency of the threaded zigzag demister with 5 threads increases by 22.7% and 16.08 %, respectively. Moreover, a higher value for the figure of merit is achieved for the threaded demister compared with the smooth unit which means that the effect of higher removal efficiency of the threaded unit is more pronounced than the effect of higher pressure drop showing the advantages of adding threads in demisters