Question

Define a constant pressure process and draw the P-V diagram for a constant pressure process 2.025k of fluid at a pressure of 3bar with a specific internal energy and specific volume of 2544kj/kg and 0.6057m³/kg respectively is heated at constant pressure until the specific internal energy is 2807kj/kg and volume is 0.2189m³. Calculate the work done and heat supplied? Hint:V²=V²/m.

Answer 1

mass = 2.025 kg

$p=2bar = 3\times 1.013\times 10^5=3.039\times 10^5pa$

$u_1=2544kj/kg$

$u_2=2807kj/kg$

$v_1=0.6057m³/kg$

$v_2=0.2189m³$

$dv=m(v_1-v_1)=2.025(0.2189-0.6057)$

$=-0.78327m^3$

$W=pdv=03.039\times 10^5(-0.7834)$

$W=-238.035KJ$

$du=(u_2-u_1)m=(2807-2544)2.025=532.575KJ$

$dQ=du+dw=532.57-238.035=294.54KJ$