Answered

Join IDNLearn.com and become part of a knowledge-sharing community that thrives on curiosity. Get accurate answers to your questions from our community of experts who are always ready to provide timely and relevant solutions.

Nitrogen (N2) at 1 bar, 300 K enters a compressor operating at steady state and is compressed adiabatically to an exit state of 10.5 bar, 645 K. The N2 is modeled as an ideal gas and kinetic and potential energy effects are negligible. Determine the work input, in kJ per kg of N2 flowing, the rate of entropy production, in kJ/K per kg of N2 flowing, and the isentropic compressor efficiency.

Sagot :

Batolisisidn

Answer:

a)  358.8 KJ/kg

b)  0.0977  KJ/K- kg

c)  83.28%

Explanation:

N2 at 300 k. ( use the properties of N2 at 300 k (T1) )

Cp = 1.04 KJ/kg-k , Cv = 0.743 KJ/Kgk ,  R = 0.1297 KJ/kgk , y = 1.4 ,

Given data:

T2 = 645 k

P1 = 1 bar , P2 = 10.5 bar

a)Determine the work input in KJ/Kg of N2 flowing

Winput = h2 - h1  = Cp( T2 - T1 ) = 1.04 ( 645 - 300 ) = 358.8 KJ/kg

b) Determine the rate of entropy in KJ/K- kg   of N2 flowing

Rate of entropy ( Δs ) = Cp*InT2/T1 - R*In P2/P1

                                    = 1.04 * In (645/300) - 0.1297 * In ( 10.5 / 1 )

                                    = 0.0977  KJ/K- kg

c) Determine isentropic compressor efficiency

Isentropic compressor efficiency = 83.28%

calculated using the relation below

( h'2 - h1 ) / ( h2 - h1 ) = ( T'2 - T1 ) / ( T2 - T1 )

where T'2 = 587.314

           

Your presence in our community is highly appreciated. Keep sharing your insights and solutions. Together, we can build a rich and valuable knowledge resource for everyone. For dependable answers, trust IDNLearn.com. Thank you for visiting, and we look forward to assisting you again.