objective(s): one applications of nanotechnology is in the area of medicine which is called nanomedicine. primary instruments in nanomedicine can help us to detect diseases and used for drug delivery to inaccessible areas of human tissues. an important issue in simulating the motion of nanoparticles is modeling blood flow as a newtonian or non-newtonian fluid. sometimes blood flow is simulated ...

Microchannel heat sinks typically consist of parallel channels connected through a common header. During flow boiling random temporal and spatial formation of vapor bubbles may lead to reversed flow in certain channels which causing an early CHF condition. Inside the microchannels the liquid surface tension forces is expected to play an important role and impact the vapor bubble growth and corr...

Flow boiling heat transfer with the refrigerants R-134a and R-245fa in copper microchannel cold plate evaporators is investigated. Arrays of microchannels of hydraulic diameter 1.09 mm and 0.54 mm are considered. The aspect ratio of the rectangular cross section of the channels in both test sections is 2.5. The heat transfer coefficient is measured as a function of local thermodynamic vapor qua...

Measurements of film mass flow rate for annular, diabatic steam-water flow in tubes are presented. The measurements were carried out with four axial power distributions and at several axial positions at conditions typical for boiling water reactors, i.e. 7 MPa pressure and total mass flux in a range from 750 to 1750 kg/ms. The results show that the influence of the axial power distribution on t...

High-fidelity simulation of flow boiling in microchannels remains a challenging problem, but the increasing interest in applications of microscale two-phase transport highlights its importance. In this paper, a volume of fluid (VOF)-based flow boiling model is proposed with features that enable cost-effective simulation of two-phase flow and heat transfer in realistic geometries. The vapor and ...

This paper is the second of a two-part study concerning two-phase flow and heat transfer characteristics of R134a in a micro-channel heat sink incorporated as an evaporator in a refrigeration cycle. Boiling heat transfer coefficients were measured by controlling heat flux (q00 = 15.9 93.8W/cm) and vapor quality (xe = 0.26 0.87) over a broad range of mass velocity. While prior studies point to e...

In the present study, commonly used weakly compressible lattice Boltzmann method and Guo incompressible lattice Boltzmann method have been used to simulate fluid flow in a stirred tank. For this purpose a 3D Parallel code has been developed in the framework of the lattice Boltzmann method. This program has been used for simulation of flow at different geometries such as 2D channel fluid flow an...

The interfacial area transport equation for a subcooled boiling flow is developed with a mechanistic model for the wall boiling source term. It includes the bubble lift-off diameter model and the lift-off frequency reduction factor model. Those models take into account a bubble’s sliding on the heated wall after a departure from the nucleate site and the coalescences of sliding bubbles. To impl...

This study develops robust numerical algorithms for the simulation of three-phase (solid-liquid-gas) boiling and bubble formation problems in rectangular channels. The are based on Finite Volume Methods (FVM) implement both volume-of-fluid (VOF) methods liquid-gas interface tracking as well volume-fraction to account concentration embedded solid nano-particles liquid phase. Water is used base-l...