The heat transfer problem of a zero-mean oscillatory flow of a Maxwell fluid between infinite parallel plates with boundary conditions of the third kind is considered. With these conditions, the amount of heat entering or leaving the system depends on the external temperature as well as on the convective heat transfer coefficient. The local and global timeaveraged entropy production are compute...

I N TWO RECENT PAPERS we have discussed the shortcomings of the concept of boundary-layer heat-transfer coefficient and developed some new approaches to thermal flow analyses which do not make use of this concept and are based on the variational and Lagrangian thermodynamics introduced earlier by this writer. The first paper,’ which deals more specifically with the local heat-transfer coefficie...

Flow boiling of water across a bank of circular staggered micro-pin fins, 250 lm long and 100 lm diameter with pitch-to-diameter ratio of 1.5, was experimentally studied for mass fluxes ranging from 346 kg/m s to 794 kg/m s and surface heat fluxes ranging from 20 W/cm to 350 W/cm. Local temperature measurements were used to elucidate the two-phase heat transfer coefficients. The flow was visual...

cooling towers are widely used in most industrial units to reject waste heat to the atmosphere. this paper deals with an experimental analysis of heat and mass transfer phenomena between water and air by direct contact in a cooling tower. the tower is filled with 6 type packing. in this study temperature and pressure drop and tower characteristics was used in determining experimentally the ther...

This paper reports an experimental study on nanofluid convective boiling heat transfer in parallel rectangular minichannels of 800 μm hydraulic diameter. Experiments are conducted with pure water and silver nanoparticles suspended in water base fluid. Two small volume fractions of silver nanoparticles suspended in water are tested: 0.000237% and 0.000475%. The experimental results show that the...

The condensation heat transfer characteristics of nonazeotropic mixtures R1234yf and R32 (mass fractions of 0.52:0.48 and 0.77:0.23, respectively) inside a horizontal smooth tube (inner diameter 4 mm) were experimentally studied at mass fluxes ranging from 100 to 300 kg/m s. A prediction model for the forced convective condensation heat transfer characteristics of nonazeotropic refrigerant mixt...

An analytical solution to the transient heat conduction for a two dimensional cylindrical fin with general boundary conditions is obtained by the principle of superposition and separation variables. In the analysis, homogeneous material properties and thickness, the convective heat transfer coefficient, the ambient temperature and the fin properties are assume to be constant. The closed form tr...

The present study aims to experimentally investigate heat transfer performance of rectangular and semicircular tubes in the presence of Ag / water nanofluids. The nanoparticles of Ag (silver) were used in seven different volume concentrations of 0.03%, 0.07%, 0.1%, 0.2%, 0.4%, 1% and 2%. The experiment was conducted in relatively low Reynolds numbers of 301 to 740. A heater with the power of 20...

In this research article a comprehensive investigation has been carried out to determine the effect of thermal cycle on temperature dependent process parameters developed during gas tungsten arc (GTA) welding of high carbon (AISI 1090) steel butt joints. An experiment based thermal analysis has been performed to obtain the thermal history. We have focused on different thermophysical properties ...

High-resolution X-ray computed tomography is employed to obtain the exact 3D geometrical configuration of porous anisotropic ceria applied in solar-driven thermochemical cycles for splitting H2O and CO2. The tomography data are, in turn, used in direct pore-level numerical simulations for determining the morphological and effective heat/mass transport properties of porous ceria, namely: porosit...