• عربي

Need Help?

Subscribe to Thermodynamics

\${selected_topic_name}
• Notes

$\begin{array}{l}{\text { Determine the specific volume of superheated water vapor at } 15 \mathrm{MPa} \text { and } 350^{\circ} \mathrm{C} \text { , }} \\ {\text { using }(\mathrm{a}) \text { the ideal-gas equation, (b) the generalized compressibility chart, }} \\ {\text { and }(\mathrm{c}) \text { the steam tables. Also determine the error involved in the first two cases. }}\end{array}$

$A-1 \longrightarrow R=0.4615$$\frac{ KPa. m^{3}}{kg.k}$

$T_{c r}=647.1 \mathrm{k}$

$P_{c r}=22.06 \mathrm{MPa}$

(a) $P v=R t \longrightarrow V=\frac{R T}{\rho}=\frac{0.4615*623.15}{15000}$

$=0.01917 \mathrm{m}^ 3 / \mathrm{kg}$

(b) $T_{R}=\frac{T}{T_{cr}}=\frac{673 K}{647.1 k}$$=1.04 \longrightarrow \text {fig} A-15$

$∴ Z=0.65 \longrightarrow V= Z_{v \ ideal}=0.65*0.01917$

$=0.01246 \mathrm{m}^ 3/ \mathrm{kg}$

(c) $A-6 \rightarrow V=0.01148 m^3/kg$

(a) $\text { error }=\frac{|0.01917-0.01148|}{0.01148} * 100 \%=67 \%$

(b) $\text { error }=\frac{|0.01 246-0.01148 |}{0.01148} * 100 \%=8.5 \%$

$\text { ideal } \longrightarrow \quad P v=R T$

$\text { Real Gags } \longrightarrow P v=Z R T$