Expansion latent heat

If an ascending air parcel reaches saturation, the addition of latent heat from condensing moisture will partially overcome the cooling due to expansion. Therefore, the saturated adiabatic lapse rate (of cooling) is smaller than y. ... 

The purpose of the evaporator is to receive low-pressure, low-temperature fluid from the expansion valve and to bring it in close thermal contact with the load. The refrigerant takes up its latent heat from the load and leaves the evaporator as a drygas. Evaporators are classified according to their refrigerant flow pattern and their function. 

Dry air rising in the atmosphere has to expand as the pressure in the atmosphere decreases. This pV work decreases the temperature in a regular way, known as the adiabatic lapse rate, Td, which for the Earth is of order 9.8 Kkm-1. As the temperature decreases, condensable vapours begin to form and the work required for the expansion is used up in the latent heat of condensation of the vapour. In this case, the lapse rate for a condensable vapour, the saturated adiabatic lapse rate, is different. At a specific altitude the environmental lapse rate for a given parcel of air with a given humidity reaches a temperature that is the same as the saturated adiabatic lapse rate, when water condenses and clouds form Clouds in turn affect the albedo and the effective temperature of the planet. Convection of hot, wet (containing condensable vapour) air produces weather and precipitation. This initiates the water cycle in the atmosphere. Similar calculations may be performed for all gases, and cloud layers may be predicted in all atmospheres. 

Specific heat at 25°C Latent heat of fusion Latent heat of vaporization Coefficient of linear expansion at 25°C Thermal conductivity at 25°C... 

Latent heat of vaporization Coeff. linear expansion 1,598 caPg... 

When large amounts of Al were added, such as 20%, the brisance was not affected. This was explained by volatilization of the Ala03, which absorbs heat. The blast effect was increased because expansion of the detonation products caused the temp to drop the AljOj vapor condensed and its latent heat of vaporization was liberated to enhance the blast effect... 

The linear coefficient of expansion of tellurium at the ordinary temperature is 0-0000344.14 The latent heat of fusion at 446° C. is 33-50 gm. cals.16... 

When any vapor expands, due to a pressure reduction (other than H2 and C02), it cools off. This is called a Joule-Thompson expansion. The reduction in temperature of the steam is called a reduction in sensible-heat content. The sensible heat of the steam is converted to latent heat of condensation. Does this mean that the latent heat of condensation of 10-psig steam is much higher than that of 450 psig steam Let s see ... 

The transition at 19° C involves an expansion of 0.0058 cm3/g (Clark and Muus). Sincethe transition temperatureincreaseswith pressure by about 0.013° C per atmosphere (Beecroft and Swenson), the latent heat is about 3.2 cal/g. These values are for the crystal and would be reduced in proportion to the crystalline content. The transition at 30° C is only about one-tenth as large. The over-all increase in entropy at these transitions is about 0.0108 cal deg-1g-1. The portion due to the increase in volume is (a// ) A V, where a is the volumetric coefficient of thermal expansion and / is the compressibility. Since the compressibility of the crystal is not known, this quantity is somewhat uncertain. Using the average of the values of a (Quinn, Roberts, and Work) and p (Weir, 1951) for the whole polymer above and below the transitions, it appears that (a/P)A V is about 0.0041 cal deg 1g 1. The entropy of the transition corrected to constant volume is, therefore, about 0.0067 cal deg g-1. 

Some of the unique properties of water that stem from it s dipolar character are as follows (1) an excellent solvent (2) thermal expansion (3) high surface tension and viscosity (4) high dielectric constant (5) high specific heat and (6) high latent heats of fusion and evaporation. 

Solid Water—Influence of Prcssuro on Melting-point—Different Kinds of leo— Density—Vapour Pressure—Expansion-—Compressibility —Specific Heat— Latent Heat of Fusion—Colloidal Ice... 

In a long note describing his experiments on the variation of the latent heat of steam with temperature, Watt acknowledged that Mr. Southern is inclined to conclude, from the experiments on the latent heat of steam at high temperature [presented in the Appendix]... that the latent heat is a constant quantity, instead of the sum of the latent and sensible heats being so .55 This seems tantamount to an abandonment of what is known as Watt s Taw - that the sum of the latent and sensible heats is a constant. Watt had used this idea not only in his development of expansive working of steam engines but also, as we will see, it was important to his ideas about the chemical transformation of water into air.56 So, to abandon Watt s Law was to jettison a key part of Watt s chemical material theory of heat. We will see shortly, however, that a place was retained for it in a clever fashion. 

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