In nature, as well as within the human-made thermal systems, the time-variable regimes are more commonly encountered, if not always, than the permanent regimes. Nevertheless, studies in convection are still more frequent in the permanent regimes, undoubtedly due to the related difficulties in calculation in terms of time and cost of computation. One may distinguish two categories of time-depend...

Roughness elements or turbulence promoters have been widely used to enhance heat transfer in cooling passages of modern gas turbine blades. Although such ribs substantially enhance heat transfer, the heat transfer coefficient is reduced immediately at corner downstream of each rib, creating hot spots. To remove such hot spots some of the ribs can be detached from the channel walls. In this pape...

This paper reports the implementation of a computer modeling approach that uses fluoroscopically measured motions of total knee replacements as inputs and predicts patient-specific implant temperature rises using computationally efficient dynamic contact and thermal analyses. The multibody dynamic simulations of two activities (gait and stair) were generated from the fluoroscopic data to predic...

There has been increasing interest of late in nanofluid boiling and its use in heat transfer enhancement. This article covers recent advances in the last decade by researchers in both pool boiling and convective boiling applications, with nanofluids as the working fluid. The available data in the literature is reviewed in terms of enhancements, and degradations in the nucleate boiling heat tran...

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 forced convective heat transfer (CHT) coefficient of a particular nanofluid, Al2O3 nanoparticles-ethylene glycol (EG) mixture, was investigated experimentally in a double-pipe heat exchanger. The nanofluid Nusselt number for different nanoparticles’ concentrations as well as various operating temperatures was measured to be increased up to 23.7% using 1.0% wt of nanoparticles. The significa...

Both fluidized sand baths and steam chambers have been used to heat laboratory reactors, in particular for studies of biomass pretreatment. In this study, several aspects of the heating performance of these devices were compared: time to heat reactors to reaction temperature, the stability of reactor temperature, and the convection coefficient. The convection coefficient was determined using co...

The effect of pulsation on the heat transfer rates, for turbulent water stream with upstream pulsation of different amplitudes, in a double-pipe heat exchanger for both parallel and counter flows, with cold water on the shell side, was investigated. Pulsation frequencies, with using a reciprocating device, ranged up to 260 cycles per minute (up to 4.3 Hz) and 5 different displacement amplitudes...