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...

Water as a refrigerant (R718) is compared with other modern refrigerants (R717, R290 R134a, R12, R22, and R152a) regarding refrigeration capacity and COP (coefficient of performance). A computer program simulating a theoretical vapor compression refrigeration cycle was developed to calculate COPs, compression ratios, and discharge temperatures of the refrigerants from the compressor. The effect...

in this paper, we are going to improve the energy efficiency of an industrial c 3 mr base load lng plant by changing its refrigerant components and its mole fractions in liquefaction and subcooling cycles based on the cooling curves generated in the main liquefaction and subcooling heat exchangers. later on, selection features of the elements will be discussed. first, non-optimized c 3 mr plant...

Configurational-bias grand-canonical transition-matrix Monte Carlo simulations are conducted to investigate various thermophysical properties, such as phase coexistence, critical properties, density and orientation profiles of liquid and vapor phases, and vapor-liquid surface tension of methane, ethane, propane, n-butane, and n-octane in bulk and slit pores of graphite and mica surfaces. An exp...

We propose a model for increasing liquid saturation in a granular packing, which can account for liquid redistribution at saturation levels beyond the well-studied capillary bridge regime. The model is capable of resolving and combining capillary bridges, menisci, and fully saturated pores to form local liquid clusters of any shape. They can exchange volume due to the local Laplace pressure gra...

This review study examines flow boiling heat transfer in micro-fin tubes using mixed and pure refrigerants with zero ozone-depleting potential (ODP) minimal global warming (GWP). investigation focuses on the extraordinary relationship between coefficients (HTCs) vapor quality. Since introduction of exchanger over 30 years ago, refrigerant-based cooling has improved significantly. Air conditioni...

The introduction of new refrigerants into the marketplace to replace CFC's banned by the Montreal Protocol has generated new research, required a review of many refrigeration concepts, and has raised new safety issues. One aspect that required further study occurred because some of the new refrigerants have a higher working pressure in the refrigeration and air conditioning equipment. This caus...

The effects of different parameters on the hydrodynamics of trickle bed reactors were discussed for Newtonian and non-Newtonian foaming systems. The varying parameters are varying liquid velocities, gas flow velocities and surface tension. The range for gas velocity is particularly large, thanks to the use of dense gas to simulate very high pressure conditions. This data bank has been used to c...

Gas diffusion layers (GDLs) are commonly known as one of the critical water management components in polymer electrolyte fuel cells with significant impact on electrochemical cell performance. Increasing levels liquid saturation GDLs, especially during high-current-density operation, limit gas transport from flow field channels to catalyst layer surfaces and hence reduce To provide GDL material...