Answer to Question #190557 in Mechanical Engineering for dev

Question

A piston cylinder device contains steam at 60 psia and 320F, and the temperature is increased to 400F through heat transfer. If the mass of the steam in the device is 15lbm and the weight of the piston is constant throughout the process. Calculate the work done during the process in Btu

Answer 1

Steam in device = 60psia

Temperature = 320°

Increase in temperature = 400°

Mass of the steam = 15lbm

Solution:

The process of expansion is quasi-equilibrium

Thus,

$W_b = \int PdV = P_o \int dv = P_o (V_2-V_1)$

$W_b= mP_o(V_2 -V_1)$

According to the steam table,

V₁ = 7.4863 and V₂ = 8.3548

Substituting the value yields;

$W_b = (10) (60) (8.3548 - 7.4863)$

$( \dfrac1{ 5.404})= 96.4\ Btu$

$\therefore$ The work done during the process is 96.4Btu.