At the atmospheric boiling point, the entropy of vaporisation per mole is roughly constant for all fluids (Trouton’s rule). Since the enthalpy of vaporisationhfg=T·sfg, it follows that fluids with a lowmolecular weight, such as water, have a large enthalpy of vaporisation and, consequently...
h specific enthalpy [J kg À1 ] I efficiency index [À] j dimensionless vapor velocity [À] L overall length of a subsection [m] lc liquid content [À] _ m refrigerant mass flow rate [kg s À1 ] M measured quantity ...
2 and 3, an exemplary refrigeration cycle of one embodiment of the refrigerant vapor compression system 2 is illustrated with reference to a carbon dioxide Pressure-Enthalpy diagram. At a point A, the refrigerant enters the compressor 12 at the suction port 44 and is pumped to a higher ...
Referring to FIGS. 2 and 3, an exemplary refrigeration cycle of one embodiment of the refrigerant vapor compression system2is illustrated with reference to a carbon dioxide Pressure-Enthalpy diagram. At a point A, the refrigerant enters the compressor12at the suction port44and is pumped to a hi...
If g is the acceleration of gravity, Vg is the gas velocity, hg is the gas enthalpy per unit mass, z is the elevation with respect to a reference point,ρ is the gas density, and ug is the gas internal energy per unit mass, then the energy-balance equation in its differential form ...
transfer databases for HFE 7100, R 134a, and water that have been amassed over the past decade at the Purdue University Boiling and Two-Phase Flow Laboratory (BTPFL). 2. Experimental methods Fig. 1 shows a flow diagram of the system developed for the ...
and that of the vapour CO2 at the temperature of the condenser inlet, respectively; while icon,in is the enthalpy of the two-phase CO2 at the condenser inlet given byicon,in=ipre,in+QpremCO2where ipre,in is the enthalpy of the liquid CO2 before entering the pre-heater, mco2 is the ...
In this paper, two-phase pressure drop data were obtained for boiling in horizontal rectangular microchannels with a hydraulic diameter of 0.55 mm for R-134a over mass velocities from 790 to 1122 kg/(m2·s), heat fluxes from 0 to 31.08 kW/m2 and vapor qualities from 0 to 0.25. The expe...