Joule-Thompson coefficient water

Where they have a positive slope, water cools on adiabatic expansion and warms if adiabatically compressed, and the two regions are separated by the Joule-Thompson inversion curve. Much the same information is contained in the enthalpy-pressure diagram (Figure 8.6), where it can be seen that constant enthalpy changes in pressure lead to increases in temperature in one region and decreases in another. The effect of dissolved NaCl on the Joule-Thompson coefficient has been calculated by Wood and Spera (1984), and the effect will be similar for other electrolytes. Because the addition of most electrolytes to water results in a decrease in V and in a, fijT is smaller, and the net effect is to move the inversion curve to higher temperatures, as shown in Figure 8.5. 

As an example of how the Joule-Thompson coefficient might be used, consider some hot spring fluids (approximated by pure water) rising vertically in the crust. When boiling begins, the pressure is 165 bars and the temperature is 350°C. At this point, VhjO = 31.35 cm mol = 0.7493 calbar mol , a = 0.01037 and C° = 43.60 calK moP, and... 

Figure 6.4 Isotherms on logP versus enthalpy in kJ moh for water. Dashed contours are the Joule-Thompson coefficient, The contour for /ajj = 0 is the Joule-Thompson inversion curve. Data from the program steam of Harvey et al. (2000).

The effect of dissolved NaCl on the Joule-Thompson coefficient has been calculated by Wood and Spera (1984), and the effect will be similar for other electrolytes. Because the addition of most electrolytes to water results in a decrease in V and in a, is smaller, and the net effect is to move the inversion curve to higher temperatures and lower pressures. 

Physical characteristics Molecular weight Vapour density Specific gravity Melting point Boiling point Solubility/miscibility with water Viscosity Particle size size distribution Eoaming/emulsification characteristics Critical temperature/pressure Expansion coefficient Surface tension Joule-Thompson effect Caking properties... 

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See also in sourсe #XX -- [ ]

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