Average Nusselt numbers were measured for R22, R290, R290/600a, and R32/152a undergoing evaporation and condensation in a brazed plate heat exchanger. The refrigerants experienced wavy, stratified flow at low heat and mass fluxes, 1.3 kW/m2 to 8.3 kW/m2 and 1.6 kg/m2 s to 19 kg/m 2 s, respectively. Heat transfer correlations from the literature for in-tube and channel flow of refrigerants with ...

A numerical finite difference study has been earned out for two dimensional radiation-natural convection interaction phenomena in a vertical circular pin located at a non-participating (i.e. transparent) fluid. The coupled conservation equations in boundary layer (continuity, momentum, and energy equations) and pin energy equation are solved simultaneously using modified box method and fully im...

An experimental investigation on heat transfer coefficient is presented from three horizontal tubes in a vertical array in a duct for 500<ReD<6000. A mass transfer measuring technique based on psychrometry chart is used to determine heat transfer coefficient. The diameter of the tubes is 11 mm each spaced 40 mm apart and in-line pitch ratio varies &#10in the range 0.055<D/W<0.22. The experimen...

An experimental investigation on heat transfer coefficient is presented from three horizontal tubes in a vertical array in a duct for 500<ReD<6000. A mass transfer measuring technique based on psychrometry chart is used to determine heat transfer coefficient. The diameter of the tubes is 11 mm each spaced 40 mm apart and in-line pitch ratio varies in the range 0.055<D/W<0.22. The experimenta...

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.

A thermosyphon is an efficient heat transfer device, which transports heat using gravity for the evaporation and condensation of the working fluid. In the present study the Box-Benhnken (BBD) design approach was chosen for the Two-Phase Closed Thermosyphon (TPCT) with CeO2 nanofluid using 0.1% volume of Nanofluid with surfactant of ethylene glycol. The experiment resulted in identifying the opt...

The present study explains a steady-state method of measuring convective heat transfer coefficient on the casing of an axial flow turbine. The goal is to develop an accurate steady-state heat transfer method for the comparison of various casing surface and tip designs used for turbine performance improvements. The freestream reference temperature, especially in the tip gap region of the casing,...

To learn about cooling of gas quenched batches, this paper reports on numerical predictions of local and average convective heat transfer coefficients, and overall pressure drops, on batches of five axially aligned, constant temperature, short cylindrical disks 25 cm diameter, 5 cm thickness with and without a concentric hole, with interdisk spacings of 5–20 cm, in axial turbulent flows of 20 b...

This paper is Part II of a two-part study devoted to measurement and prediction of the saturated flow boiling heat transfer coefficient in water-cooled micro-channel heat sinks. Part I discussed the experimental findings from the study, and identified unique aspects of flow boiling in micro-channels such as abrupt transition to the annular flow regime near the point of zero thermodynamic equili...