The properties of saturated liquids and vapors at various conditions are given in saturated vapor tables, which usually list values for the follwing properties: (1) temperature, (2) pressure, (3) specific volume, (4) enthalpy, and (5) entropy (Fig. 4-8). The temperature given is the saturation temperature of the fluid and is usually listed in the extreme left-hand column as the entry property to the table. Normally, the corresponding saturation pressure is listed in the second column and is followed by the specific volume for both the liquid and the vapor states in the third and fourth columns, respectively. Some tables list the density in addition to, or in place of, the specific volume is wanted, the specific volume is found by dividing the density into 1. Likewise, when the specific volume is given and the density is wanted, the density is found by taking the reciprocal of the specific volume.
Three values for enthalpy are listed in most table: (1) the enthalpy of the saturated liquid (hf), which is the summation of the energy required to raise the temperature of the liquid from the temperature at the assumed zero point of the enthalpy calculation to the saturation temperature listed in column one; (2) the enthalpy of vaporization (hf), which is the latent heat of vaporization at the given saturation temperature; and (3) the enthalpy of the saturated vapor(hg), which is the sum of the enthalpy of the liquid (hf) and the enthalpy of vaporization(hfg). When the enthalpy of vaporization is not listed, it can be determined by subtracting hf from hg.
Two values of entropy are usually listed: sf, the entropy of the saturated liquid, and sg, the entropy of the saturated vapor. Some tables also list a value for sfg, ewhich is the change in the entropy during the change in phase. When this value is not listed, it can be determined by subtrancting sf from sg.
Some tables also list values for the internal energy of the fluid in both the liquid and vapor phases. When this is not the case, the value for the internal energy of the fluid in either phase can be computed by rearranging and applying Equation 4-1 to solve for the internal energy u
It has been stated previously that the condition of a gas or a capor can be determined when any two of its properties are known. However, for a saturated liquid or vapor at any one pressure, there is only one temperature that the fluid can have and still satisfy the conditions of saturation. This is true also for the other properties of a saturated liquid or vapor. Therefore, if either the temperature or the pressure of a saturated liquid or vapor is known, the value of the other properties can be read directly from the saturated vapor table.
The properties of saturated liquids and vapors at various conditions are given in saturated vapor tables, which usually list values for the follwing properties: (1) temperature, (2) pressure, (3) specific volume, (4) enthalpy, and (5) entropy (Fig. 4-8). The temperature given is the saturation temperature of the fluid and is usually listed in the extreme left-hand column as the entry property to the table. Normally, the corresponding saturation pressure is listed in the second column and is followed by the specific volume for both the liquid and the vapor states in the third and fourth columns, respectively. Some tables list the density in addition to, or in place of, the specific volume is wanted, the specific volume is found by dividing the density into 1. Likewise, when the specific volume is given and the density is wanted, the density is found by taking the reciprocal of the specific volume.
Three values for enthalpy are listed in most table: (1) the enthalpy of the saturated liquid (hf), which is the summation of the energy required to raise the temperature of the liquid from the temperature at the assumed zero point of the enthalpy calculation to the saturation temperature listed in column one; (2) the enthalpy of vaporization (hf), which is the latent heat of vaporization at the given saturation temperature; and (3) the enthalpy of the saturated vapor(hg), which is the sum of the enthalpy of the liquid (hf) and the enthalpy of vaporization(hfg). When the enthalpy of vaporization is not listed, it can be determined by subtracting hf from hg.
Two values of entropy are usually listed: sf, the entropy of the saturated liquid, and sg, the entropy of the saturated vapor. Some tables also list a value for sfg, ewhich is the change in the entropy during the change in phase. When this value is not listed, it can be determined by subtrancting sf from sg.
Some tables also list values for the internal energy of the fluid in both the liquid and vapor phases. When this is not the case, the value for the internal energy of the fluid in either phase can be computed by rearranging and applying Equation 4-1 to solve for the internal energy u
It has been stated previously that the condition of a gas or a capor can be determined when any two of its properties are known. However, for a saturated liquid or vapor at any one pressure, there is only one temperature that the fluid can have and still satisfy the conditions of saturation. This is true also for the other properties of a saturated liquid or vapor. Therefore, if either the temperature or the pressure of a saturated liquid or vapor is known, the value of the other properties can be read directly from the saturated vapor table.
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