Helium is compressed from 100 kPa and 7°C to 300 kPa and 227°C. Assuming constant specific heats, determine the change in the specific entropy of helium.

 Helium is compressed from 100 kPa and 7°C to 500 kPa and 227°C. Assuming constant specific heats, determine the change in the specific entropy of helium.

Helium is compressed from 100 kPa and 7°C to 500 kPa and 227°C. Assuming constant specific heats, determine the change in the specific entropy of helium. 

 

initial Pressure, `P_{1}` = 100 Kpa = 100000 Pa

Initial Temprature,`T_{1}`= 7°C = 280K



final Pressure, `P_{2}` = 300 Kpa = 300000 Pa

final Temprature, T₁ = 227 °C = 500 K

Now.

Specific Entropy change of helium , s = `C_{p}`ln`frac{T_{2}}{T_{1}}` -Rln`frac{P_{2}}{P_{1}}`

  

                                                           s =  (5233.5)ln`frac{500}{280}` -(2078)ln`frac{300000}{100000}`

 

 

                                                          s = 3034.48 - 2282.91

                                                          s = 751.57 J/Kg.K

Specific Entropy change of helium is 751.57 J/Kg.K

`