Steam at 10 bar absolute pressure and 0.95 dry enters a super heater a

1.	Steam at 10 bar absolute pressure and 0.95 dry enters a super heater and leaves at the same pressure at 250°C. Determine the change in entropy per kg of steam. Take Cps = 2.25 kJ/kg K.
Answer» Given that : P =10bar x = 0.95 t_sup= 250°C From Saturated steam table t_sat= 179.9 Now, entropy of steam at the entry of the superheater s₁ = s_f1 + x₁s_fg1 = 2.1386 + 0.95 × 4.4478 = 6.3640 kJ/kg K entropy of the steam at exit of superheater s₂ = s_gf + C_ps ln(T_sup/T_sat) = 6.5864 + 2.25 ln (250+ 273/179.9 +273) = 6.9102 kJ/kg K Change in entropy = s₂ – s₁ = 6.9102 – 6.3640 = 0.5462 kJ/kg K

Steam at 10 bar absolute pressure and 0.95 dry enters a super heater and leaves at the same pressure at 250°C. Determine the change in entropy per kg of steam. Take Cps = 2.25 kJ/kg K.

Answer»

Given that :

P =10bar

x = 0.95

t_sup= 250°C

From Saturated steam table

t_sat= 179.9

Now, entropy of steam at the entry of the superheater

s₁ = s_f1 + x₁s_fg1

= 2.1386 + 0.95 × 4.4478 = 6.3640 kJ/kg K

entropy of the steam at exit of superheater

s₂ = s_gf + C_ps ln(T_sup/T_sat)

= 6.5864 + 2.25 ln (250+ 273/179.9 +273)

= 6.9102 kJ/kg K

Change in entropy = s₂ – s₁ = 6.9102 – 6.3640

= 0.5462 kJ/kg K

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Steam at 10 bar absolute pressure and 0.95 dry enters a super heater and leaves at the same pressure at 250°C. Determine the change in entropy per kg of steam. Take Cps = 2.25 kJ/kg K.

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