the fluid flow and heat transfer in a three-dimensional microchannel filled with al2o3- water nanofluid is numerically investigated. the hybrid scheme is used to discretize the convection terms and simpler algorithm is adopted to couple the velocity and pressure field in the momentum equations. the thermal and flow fields were analyzed using different volume fractions of nanoparticles and diffe...

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A total of 1210 new condensation friction pressure gradient points (database) is collected from 12 open articles on mini/micro-channels literature. The database covered a wide range thermophysical properties associated with low-GWP refrigerants, physical dimension, mass velocity and vapor quality. comparison the experimental against eleven two-phase flow frictional drop prediction tools carried...

The pressure drop characteristics of supercritical carbon dioxide (S-CO 2 ) are experimentally studied in horizontal rectangular microchannels with hydraulic diameters 1 and mm, which used printed circuit heat exchangers. operating conditions include an 9–12 MPa, a mass flux 290–1200 kg/m s, 25–50 kW/m . four contributors to the S-CO were investigated. results indicate that total decreases for ...

One-dimensional modeling of steady frictional radial flow of a perfect gas through a high-pressure piezoelectrically actuated microvalve under low leak-rate conditions is studied. Focusing on the micro-scale gap between the boss and seat plates, a model was developed for axisymmetric flow between two thermally insulated, parallel disks flowing radially toward an outlet hole at the center of the...

The thermodynamic analysis of irreversible processes has an important influence in energy efficiency growing of any thermodynamic processes or systems. All of thermodynamic processes are entropy generators but there are processes with such a high level of irreversibility so that couldn’t be ignored. That is why is so important to provide a feel for what causes entropy generation and to identify...