In this study, condensation heat transfer experiments were conducted with two types of plate and shell heat exchangers (P&SHE) using R-134A. An experimental refrigerant loop has been established to measure the condensation heat transfer coefficient of R-134A in a vertical P&SHE. Two vertical counter flow channels were formed in the P&SHE by stacking three plates of geometry with a corrugated tr...

the produced liquid water in cathode catalyst layer (ccl) has significant effect on the operation of proton exchange membrane fuel cell (pemfc). to investigate this effect, the transport of oxygen in ccl in the presence of immiscible liquid water is studied applying a two-dimensional pore scale model. the ccl was reconstructed as an agglomerated system. to explore the wettability effects, diffe...

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...

We developed an equation of state (EOS) by Ihm, Song, and Mason (ISM) for polar fluids. The model consists of four parameters, namely, the second virial coefficient, an effective van der Waals co-volume, a scaling factor, and the reduced dipole moment. The second virial coefficient is calculated from a correlation that uses the heat of vaporization, and the liquid density at the normal boiling ...

In this study the intermolecular potential energies of some environment-friendly industrial HFC refrigerants were obtained through the inversion method which is based on the corresponding states principle. These potentials were later employed in calculation of transport properties (viscosity, diffusion, thermal conductivity and thermal diffusion factor) of some binary and ternary refrigerant mi...

Refrigerant mixtures seem the most promising candidates as replacement fluids in refrigeration devices and heat pumps. In this paper two prediction methods are proposed for th~ evaluation of the thermal conductivity of refrigerant mixtures in their saturated liquid state and in the subcooled region. The first method is based on the use of mixing rules applied to pure refrigerant data evaluated ...

the examination of available vapor pressure data in the case of the methane, ethane, propane and butane halogenated refrigerants, allowed recommendations of standard equations for this property. in this study, three new models include a general correlation; a substance-dependent correlation and an artificial neural network (ann) approach have been developed to estimate the saturated vapor press...