Page 39 - BASIC CONCEPTUAL OF THERMOFLUID

EXAMPLE 5
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Steam at 100 bar has a specific volume of 0.02812 m /kg. Find the temperature, degree of
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superheat, specific enthalpy and specific internal energy. (t = 425 C, degree of superheat = 114 C,
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v=2.812 x10 m /kg, h= 3172 kJ/kg, u=2890.8 kJ/kg)
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EXERCISE
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Steam at 120 bar is at 500 C. Find the degree of superheat, specific volume, specific enthalpy and
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specific internal energy. (degree of superheat = 175.4 C, v=2.677 x10 m /kg, h=3348 kJ/kg,
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u=3026.76 kJ/kg)
3.6 INTERPOLATION
The first interpolation problem that an engineer usually meets is that of “reading between the lines” of a
published table, like the Steam Tables.It is common to use linear interpolation as shown in figure 2.8

FIGURE 3.6 linear interpolation

3.6.1 Single Interpolation

Single interpolation is used to find the values in the table when one of the values is not tabulated

EXAMPLES 6
1. Determine the saturation temperature at 77 bar. (ts=292.3 C)
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2. Determine the specific enthalpy of dry saturated steam at 103 bar. (hg=2719 kJ/kg)
3. Determine the specific volume of steam at 8 bar and 220 C. (v=0.27392 m /kg)
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