Can someone please help me with this? I am desperate right now, I need any help

Question

Can someone please help me with this? I am desperate right now, I need any help you can offer. Please, anything....

Water at 27 degree C (rho = 1000 kg/m3) is pumped adiabatically from 1 bar to 19.7 bar in a steady flow process. Find the minimum work magnitude (assuming delta KE 0). -0.197 kj/kg -19.7 kj/kg -1.87 kj/kg -1870 kj/kg Repeat the minimum work calculation, but now for compressing air (ideal) instead of pumping water. Assume inlet temperature and inlet/exit pressures are the same as for the water. Use nearest table value in the air table. -402 kj/kg -300 kj/kg -197 kj/kg -390 kj/kg Repeat part b, but assume constant air properties evaluated at 300k (Table A-20). -405 kj/kg -303 kj/kg -194 kj/kg -393 kj/kg

Explanation / Answer

So the process is adiabatic

Workdone= R(t2-t1)/y-1

So y(gamma) for water= 1.24

We know that PVy=constnt

Therefore

P1(1-y)Ty=P1(1-y)T2y
there fore with given pressure we calculate

(1/19.4)1-1.24*3001.24=T21.24

T2=534K

W= 8.314*( 300-534)/1.24-1

= -19.7KJ/Kg

SIMILARLY FOR AIR Y= 1.4

So with same temp range

We hav to find t2

T2={(1/19.7)1-1.4*3001.4}1/1.4

T2=703k

Workdone=R(t2-t1)/y-1

=8.314*(300-703)/1.4-1

=-402KJ/Kg

At constant property

The workdone = -392kJ/kg

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