This report summarizes our three-year effort on advanced micro and nanostructures for fundamental studies of fluid manipulation and enhanced two-phase heat transfer. First, we studied the role of micro/nanostructures on pool boiling heat transfer. We fabricated well-defined microstructured surfaces in silicon and performed systematic pool boiling experiments in which we demonstrated that increa...

Vapor-venting microchannel heat exchangers are promising because they address the problems of high pressure drop, flow instability, and local dryout that are common in conventional two-phase microchannel heat sinks. We present a 3D numerical simulation of the vapor-venting process in a rectangular microchannel bounded on one side by a hydrophobic porous membrane for phase-separation. The simula...

in this paper the heating process in a box annealing unit is simulated and the effect of various parameters involved in the process is examined. for this purpose, the full naiver-stokes equations along with the standard k- turbulence model are solved in the fluid region using the finite volume approach. in the solid area the conduction heat transfer equation is employed using approporate surfac...

The present study extends the range of flow patterns observed during boiling of water in a single minichannel of height 197 μm and width 1054 μm. The calculated hydraulic diameter of the channel is 333 μm. High-speed photography is used to obtain video images of the flow field. The top covers of the channels are made of Lexan to permit visual observation, while the minichannel is machined in a ...

Solar collector water heating system use solar thermal energy to provide hot for domestic and industrial use. These systems are operated either as open-loop or closed-loop flow circuit. The former loop not recommended the cold climates having freezing problem. Although previous studies on collectors have used operation with working fluid. However, it must high boiling low points colder regions ...

We present a technique for synthesizing spatially and temporally varying textures on continuous flows using image or video input, guided by the physical characteristics of the fluid stream itself. This approach enables the generation of realistic textures on the fluid that correspond to the local flow behavior, creating the appearance of complex surface effects, such as foam and small bubbles. ...

Computational analysis of nucleate boiling occurring in liquid cooled applications, such as internal combustion engines is often implemented within a single phase Fluid Dynamics (CFD) framework, owing to low vapor fractions involved. With increase specific power and the resulting higher thermal loads, accounting for presence using multiphase framework required certain conditions, despite comput...

Pulse ultrasound technique has been applied to measure the reflected echo signals from vapor bubbles in boiling two-phase flow. In this study, an ultrasonic transducer was developed for the ultrasonic measurement in boiling two-phase flow under the atmospheric pressure. Since the Curie point of piezoelements of the transducer is above 250 ̊C, it has an allowable temperature limit of 120 ̊C. The b...