Abstract. This paper presents results of an experimental study on heat exchanger consisting of finned tube.The presented method for determining the local heat transfer coefficient on external tube surfaces is characterized by very high accuracy and can be applied to determine the spatial heat transfer distribution on objects with a complex shape. As a results of experimental and numerical inves...

Several approaches to numerical modelling of liquid droplet heating and evaporation by convection and radiation from the surrounding hot gas are discussed. The finite thermal conductivity of liquid, recirculation in droplets, and time dependence of gas temperature and the convection heat transfer coefficient are taken into account. For the constant and almost constant convection heat transfer c...

In this paper the steady laminar magneto hydrodynamic (MHD) mixed convection boundary layer flow towards a vertical stretching sheet with variable fluid viscosity, radiation and in the presence of Dufour’s effect have been investigated. The governing partial differential equations are transformed into set of ordinary differential equations using similarity transformation, and then these equatio...

It is shown that there exists an optimal spacing of thermo-sensors in the determination of the experimental heat transfer coefficient of a fluid flowing over a plate. The problem is considered as an inverse heat transfer problem with long thin fin model. The heat transfer coefficient of the fluid is estimated from simulated steady-state temperature measurements along the plate. It is shown theo...

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...

Correlation of heat transfer coefficients for air flow through the regenerator constructed from randomly paked spheres is reported for the symmetric-balanced mode of operation. The experimental results have been correlated by the least square regression has been obtained.The present correlation has been compared with the heat transfer coefficient correlations in the literature.

Accurate and optimum usage of energy sources is gaining importance all over the world due to the increase of energy need and limited energy sources. Optimum usage of energy sources is not only necessity for energy conversion systems, but also design and production of energy conversion devices. Therefore optimization of condensers is very important for HVAC systems which require as possible as m...

When solid materials and devices scale down in size, heat transfer from the active region to the gas environment becomes increasingly significant. We show that the heat transfer coefficient across the solid-gas interface behaves very differently when the size of the solid is reduced to the nanoscale, such as that of a single nanowire. Unlike for macroscopic solids, the coefficient is strongly p...

In this study the Taguchi method, has been applied to optimize the heat treatment parameters for the corrosion resistance of AA6061 aluminum alloy. The experimental design consisted of four parameters (aging temperature, aging time, quenching environment and NaCl concentration), each containing three levels. Tafel polarization measurements were carried out to determine the corrosion resistance ...