VAPOR PRESSURE AND SATURATION TEMPERATURE

2014 ◽  
pp. 119-144
2015 ◽  
Vol 54 (39) ◽  
pp. 9627-9636 ◽  
Author(s):  
Pedro Vargas ◽  
Jorge Lovera ◽  
Alberto Coronas ◽  
Daniel Salavera ◽  
Angel Fernández ◽  
...  

Author(s):  
Hongfang Gu ◽  
Haiyang Guo ◽  
Haijun Wang ◽  
Yuqiang Gu

Fog formation occurs if the vapor pressure in the gas-phase is higher than the saturated vapor pressure and the bulk temperature is lower than its saturation temperature (supersaturated) for condensation in the presence of non-condensable gases. Generally, fogging is formation of entrained small droplets mixing in the vapor-gas stream, and the vapor condenses at the mist-flow and share-controlled flow regime. The phenomenon and mechanism of fogging need to be considered for determining condensation rate and separation of the condensate from vapor-gas phase for the down-stream process. The experimental study of shell-side condensation using steam mixing with non-condensable air was conducted in a shell-side horizontal baffled tube bundle. Experimental data has been obtained including visualization findings using high-speed photograph. The characteristics of fog formation related to the heat and mas transfer performance are analyzed based on experimental data and observation. The general equation for determining fog formation (degree of supersaturation) is evaluated with experimental data. Results confirm that the transition band of fogging formation is in the range of S = 1.0 to 1.75. This paper presents experimental data and visualization findings on fogging characteristics and heat transfer performance for condensation in the presence of non-condensable gas.


Author(s):  
A. C. Faberge

Benzylamine tartrate (m.p. 63°C) seems to be a better and more convenient substrate for making carbon films than any of those previously proposed. Using it in the manner described, it is easy consistently to make batches of specimen grids as open as 200 mesh with no broken squares, and without individual handling of the grids. Benzylamine tartrate (hereafter called B.T.) is a viscous liquid when molten, which sets to a glass. Unlike polymeric substrates it does not swell before dissolving; such swelling of the substrate seems to be a principal cause of breakage of carbon film. Mass spectroscopic examination indicates a vapor pressure less than 10−9 Torr at room temperature.


Author(s):  
V. R. Matricardi ◽  
G. G. Hausner ◽  
D. F. Parsons

In order to observe room temperature hydrated specimens in an electron microscope, the following conditions should be satisfied: The specimen should be surrounded by water vapor as close as possible to the equilibrium vapor pressure corresponding to the temperature of the specimen.The specimen grid should be inserted, focused and photo graphed in the shortest possible time in order to minimize dehydration.The full area of the specimen grid should be visible in order to minimize the number of changes of specimen required.There should be no pressure gradient across the grid so that specimens can be straddled across holes.Leakage of water vapor to the column should be minimized.


2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Viorel Feroiu ◽  
Dan Geana ◽  
Catinca Secuianu

Vapour � liquid equilibrium, thermodynamic and volumetric properties were predicted for three pure hydrofluorocarbons: difluoromethane (R32), pentafluoroethane (R125) and 1,1,1,2 � tetrafluoroethane (R134a) as well as for binary and ternary mixtures of these refrigerants. Three cubic equations of state GEOS3C, SRK (Soave � Redlich � Kwong) and PR (Peng � Robinson) were used. A wide comparison with literature experimental data was made. For the refrigerant mixtures, classical van der Waals mixing rules without interaction parameters were used. The GEOS3C equation, with three parameters estimated by matching several points on the saturation curve (vapor pressure and corresponding liquid volumes), compares favorably to other equations in literature, being simple enough for applications.


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