Heat and vapour convective surface coefficients are required in practically all heat and vapour transport calculations. In building envelope research, such coefficients are often assumed constants for a set of conditions. Heat transfer surface coefficients are often determined using empirical correlations based on measurements of different geometry and flows. Vapour transfer surface coefficient...

The objective of the present chapter is to analyze the radiation and mass transfer effects on an unsteady two-dimensional laminar mixed convective boundary layer flow of a viscous, incompressible, electrically conducting chemically reacting fluid, along a vertical moving semi-infinite permeable plate with suction, embedded in a uniform porous medium, in the presence of transverse magnetic field...

The effect of chemical reaction on mixed convection heat and mass transfer in non-Newtonian fluid a long non-isothermal horizontal surface embedded in a saturated porous medium has been studied. The mixed convection regime is divided into two regions, namely, the forced convection dominated regime and the free convection dominated regime. The two solutions are matched. Numerical calculations ar...

The present study focused on the investigation of the effects of roughness elements on heat transfer during natural convection in a rectangular cavity using numerical technique. Roughness elements were introduced on the bottom hot wall with a normalized amplitude (A*/H) of 0.1. Thermal and hydrodynamic behaviors were studied using computational method based on Lattice Boltzmann method (LBM). Nu...

A finite element model has been used in order to study the mixing process of species in a 100-microm-wide zigzag microchannel integrating a "Y" inlet junction. The distribution of the concentration was obtained by solving successively the Navier-Stokes equation and the diffusion-convection equation in the steady state form. Because of the large range of Reynolds numbers studied (1 < Re < 800), ...

This paper presents and discusses the numerical simulations of transient laminar natural convection cooling of high Prandtl number fluids in cubical cavities, in which the six walls of the cavity are subjected to a step change in temperature. The effect of the fluid Prandtl number on the heat transfer coefficient is studied for three different fluids (Golden Syrup, Glycerin and Glycerin-water s...

This work presents the application of density-based topology optimisation to the design of three-dimensional heat sinks cooled by natural convection. The governing equations are the steady-state incompressible Navier-Stokes equations coupled to the thermal convection-diffusion equation through the Bousinessq approximation. The fully coupled non-linear multiphysics system is solved using stabili...

A model for steady laminar natural convection inside vertical, arbitrarily shaped isothermal ducts of constant cross section is presented. The model is based on a combination of asymptotic solutions for fully developed and developing, boundary-layer  ow. The fully developed asymptote model utilizes forced convection, internal  ow modeling techniques, and an approximate model is presented, whi...

The hydrodynamic and thermal lattice Boltzmann methods are applied to investigate the turbulent convective heat transfer in the wavy channel flows. In this study, the turbulent phenomena are modeling by large-eddy simulations with the Smagorinsky model. As a benchmark, the laminar and turbulent backward-facing step flows are simulated first. The results give good agreement with other numerical ...

The stirring of a small, passive heterogeneity in an unsteady circulation is investigated by following the boundary of the heterogeneity; the circulation mimics features of plate-scale flow. After initial release, the heterogeneity is stirred and subsequently consists of at least one large "blob" connected to long, but thin tendrils. Tendrils exponentially lengthen and exponentially thin with t...