Saturated Water Pressure Table

TABLE B.1 Saturated Water Temperature Table [648] TABLE B.2 Saturated Water Pressure Table [650]... 

Table A-2 Boiling and freezing point properties 843 Table A-3 Properties of solid metals 844 846 Table A-4 Properties of solid nonmetals 847 Table A-5 Properties of building materials 848-849 Table A-6 Properties of insulating materials 850 Table A-] Properties of common foods 851-852 Table A-8 Properties of miscellaneous materials 853 TableA-9 Properties of saturated water 854 Table A 10 Properties of saturated refrigerant-134a 855 Table A-11 Properties of saturated ammonia 856 Table A-12 "Properties of saturated propane 857 Table A-13 Properties of liquids 858 Table A-14 Properties of liquid metals 859 Table A- 5 Properties of air at 1 atm pressure 860 TableA-16 Properties of gases at 1 atm pressure 861-862 Table A-17 Properties of the atmosphere at high altitude 863 Table A-18 Emissivities of surfaces 864-865 Table A-19 Solar radiative properties of materials 866 Figure A-20 The Moody chart for friction factor for fully developed flow in circular pipes 867...

Temperature influences the rate of drying in a number of ways. The principal reason for kiln drying at high temperatures is to increase the rate of moisture transfer to the wood surface. Raising the temperature dramatically enhances the rate of diffusion of water molecules across cell walls. The rate of diffusion increases with temperature at approximately the same rate, as does the saturated vapour pressure (Table 8.1 Figure 8.9b). 

State 1 is completely constrained. Looking up values for internal energy in the steam tables for saturated water pressure (Appendix B.2) gives ... 

The term aquifer is used to denote an extensive region of saturated material. There are many types of aquifers. The primary distinction between types involves the boundaries that define the aquifer. An unconfined aquifer, also known as a phraetic or water table aquifer, is assumed to have an upper boundary of saturated soil at a pressure of zero gauge, or atmospheric pressure. A confined aquifer has a low permeabiUty upper boundary that maintains the interstitial water within the aquifer at pressures greater than atmospheric. For both types of aquifers, the lower boundary is frequendy a low permeabihty soil or rock formation. Further distinctions exist. An artesian aquifer is a confined aquifer for which the interstitial water pressure is sufficient to allow the aquifer water entering the monitoring well to rise above the local ground surface. Figure 1 identifies the primary types of aquifers. 

This shows that the presence of air in the gas phase has a very small influence on the vapor pressure of water. Repeating the same calculation procedure for other temperatures, we can show that the vapor pressure of water can with good accuracy be taken from the vapor pressure tables for saturated water (water has the same pressure as water vapor when they are in equilibrium), as though there were no air in the gas phase. So the vapor pressure of water is with good accuracy also in this case just a function of temperature, and Eq. (4.97) is valid. New vapor pressure tables will not be needed for calculations with humid air. 

Saturated water vapor pressure is most accurately found from vapor tables or can be approximated with the following equation ... 

Relative humidity is usually considered only in connection with atmospheric air, but since it is unconcerned with the nature of any other components or the total mixture pressure, the term is applicable to vapor content in any problem. The saturated water vapor pressure at a given temperature is always known from steam tables or charts. It is the existing partial vapor pressure which is desired and therefore calculable when the relative humidity is stated. 

If air and water are present together in a confined space, a balance condition will he reached where the air has become saturated with water vapour. If the temperature of the mixture is known, then the pressure of the water vapour will be the pressure of steam at this temperature (see also Section 1.3) (Table 23.1). Dalton s Taw of partial pressures (see also Section 1.5) states that the total pressure of a mixture of gases is equal to the sum of the individual pressures of the constituent gases, taken at the same temperature and occupying the same volume. Since the water saturation vapour pressure will remain constant, depending on temperature and not on volume, this pressure can be obtained from steam tables as below. The partial pressure exerted by the dry air must therefore be the remainder. 

Thus, if the saturated vapor pressure is known at the azeotropic composition, the activity coefficient can be calculated. If the composition of the azeotrope is known, then the compositions and activity of the coefficients at the azeotrope can be substituted into the Wilson equation to determine the interaction parameters. For the 2-propanol-water system, the azeotropic composition of 2-propanol can be assumed to be at a mole fraction of 0.69 and temperature of 353.4 K at 1 atm. By combining Equation 4.93 with the Wilson equation for a binary system, set up two simultaneous equations and solve Au and A21. Vapor pressure data can be taken from Table 4.11 and the universal gas constant can be taken to be 8.3145 kJ-kmol 1-K 1. Then, using the values of molar volume in Table 4.12, calculate the interaction parameters for the Wilson equation and compare with the values in Table 4.12. 

Saturated vapor pressure of water at 25°C (from steam tables)... 

The most important data during main drying is the temperature at the moving sublimation front which cannot be measured by Ths or RTDs. In 1958, Neumann and Oetjen 11.651 showed that the barometric temperature measurement (BTM) measures exactly this data. In Fig. 1.77 this is schematically shown if the drying chamber is separated from the condenser by a valve for a short time the pressure in the chamber rises to the saturation vapor pressure (ps) corresponding to the temperature of the sublimation front. ps can be converted into the ice temperature by the water vapor- temperature diagram (e. g. 0.3 mbar = -30 °C). Data for accurate conversion are given in Table 1.11 the temperatures between -100 and -1 °C. 

The gas ballast facility (see Fig. 2.13) prevents condensation of vapors in the pump chamber of the pump. When pumping vapors these may only be compressed up to their saturation vapor pressure at the temperature of the pump. If pumping water vapor, for example, at a pump temperature of 70 °C, the vapor may only be compressed to 312 mbar (saturation vapor pressure of water at 70 °C (see Table XIII In Section 9)). When compressing further, the water vapor condenses without Increasing the... 

Because water is generally considered incompressible, applying pressure to the water table surface depresses the water proportionally to the water pressure. This pressure causes a radial depression of the water table about the pressure injection point. The depression dewaters a section of the smear zone and saturated zone proportionally to the pressure applied at the injection point. Dewatering of the smear zone increases the volume of the smear zone and... 

The following table provides the temperature dependence of the saturated vapor pressure and vapor density of water. This information is useful in gas chromatographic headspace analysis and for SPME sampling.12... 

Table 3.2 Saturated vapour pressure (p5 ) for water over a range of temperatures...

At 20° the concentration of saturated water vapor is such that its pressure is 17.4 mm. At other temperatures the concentration is different, but it has an absolutely definite value for each temperature. The pressure of saturated water vapor has been carefully measured at different temperatures. The values from 0° to 100° are given in the table on page 353 in the Appendix. 

Compute the final-state conditions of saturated water. Determine the enthalpy of 500-psia (3447.5-kPa) saturated water from the saturation-pressure steam table at 500 psia (3447.5 kPa) H = hf = 449.4 Btu/lb (1045.3 kJ/kg) = H2, by definition. The T-S diagram (Fig. 19.8) shows that the throttled water contains some steam vapor. Or, comparing the final enthalpy of 449.4 Btu/lb (1045.3 kJ/kg) with the enthalpy of saturated liquid, 180.07 Btu/lb (418.8 kJ/kg), at the final pressure, 14.7 psia (101.4 kPa), shows that the liquid contains some vapor in the final state because its enthalpy is greater. 

The commonly used expression Vapor Pressure Deficit or VPD is the partial pressure of water vapor in the leaf intercellular air spaces, minus the partial pressure of water vapor in the turbulent air outside the boundary layer, P 0,. Often P af is calculated as the saturation water vapor partial pressure at the temperature of the leaf (for a leaf water potential of -1.4 MPa at 20°C, this leads to an error of only 1% in Pj. af Table 2-1). P a, equals the air relative humidity times the saturation water vapor partial pressure (P. w) at the air temperature (values of P , in kPa, which can be used to calculate P f and P 0, are given at the end of Appendix I). 

Atmospheric air can be viewed as a mixture of dry air and water vapor, and the atmospheric pressure is the sum of the pressure of dry air and the pressure of water vapor, which is called the vapor pressure P . Air can hold a certain amount of moisture only, and the ratio of the actual amount of moisture in the air at a given temperature to the maximum amount air can hold at that temperature is called the relative humidity (f>. The relative humidity ranges from 0 for dry air to 100 percent for saturated air (air that cannot hold any more moisture). The partial pressure of water vapor in saturated air is called the saturation pressure Table 14 9 lists the saturation pressure at various teraperaturest... 

The saturated zone is formed by porous material in which all the pore spaces are filled with water. The water table is defined as the depth at which pore water pressure equals atmospheric pressure. If a hole is dug down to the saturated zone, the location of the water table can be easily determined it is at the depth to which water accumulates in the hole. In coarse porous material, the location of the water table itself very nearly approximates the transition between saturated and unsaturated material in a fine-textured porous material, enough water may move upward by capillarity to cause complete saturation of a measurable thickness above the water table (the capillary fringe). 

In a water-saturated porous medium, water movement occurs from areas of higher hydraulic head to areas of lower hydraulic head. The gauge water pressure at the water table (or at any other interface between free-standing water and the atmosphere, such as the water surface in a pond), is by defini-... 

Relative humidity of air is defined as the vapour pressure of water vapour in a given volume of air divided by the saturated vapour pressure. The absolute humidity at saturation (in g m ) and the saturated vapour pressure of water are shown in Table 8.1. Thus a cubic metre of saturated air can hold 17 g of water vapour at 20°C, 130 g at 60°C and 600 g at 100°C. In the wider drying literature, absolute humidity is normally given as a mass ratio of water vapour to the mass of dry air (kg kg dry basis), since the flow rates of dry air and dry solids through any process are normally constant. 

Water table The surface of an unconfined aquifer at which the pore water pressure is atmospheric. Also, the level to which water will rise in a well installed a few feet or meters into the saturated zone. 

The Kelvin equation can be combined with the relative humidity, RH, if water is involved as the fluid relative humidity indicates how moist the air is. The amount of water vapor in the air at any given time is usually less than that required to saturate the air. The relative humidity is the percentage of saturation humidity, generally calculated in relation to the saturated vapor density. Relative humidity may be defined as the ratio of the water vapor density (mass per unit volume) to the saturation water vapor density, usually expressed in percent. Relative humidity is also approximately equal (exactly equal when water is assumed as an ideal gas) to the ratio of the actual water vapor pressure to the saturation water vapor pressure, RH = PJP°. The P° values corresponding to each temperature are given in tables which can be found in handbooks. If RH is measured in an experiment, then Pv can be calculated by using the saturation water vapor pressure tables and can be inserted into the Kelvin equation. 

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