Chapter 7, Problem 7.28P

Interpretation Introduction

Interpretation:

In an expansion process find out ideal work, the thermodynamic efficiency of the process, lost work and rate of entropy generation in the process.

Concept introduction:

Expansion process is an increasing volume process. Free expansion in a process has been always irreversible. Ideal work in this process can be calculated by equation:

Ideal work during expansion:

  $W=\stackrel{.}{m}\left[\Delta H-T_{\sigma }\Delta S\right]$

The efficiency of any process can be calculated by dividing the actual work required in a process to ideal work required for the same process.

$\eta =\frac{W_{actual}}{W_{ideal}}$

Rate of entropy generation:

  $\Delta S_g=\stackrel{.}{m}\left(S_2-S_1\right)$

Lost work calculated by the equation given below:

  $W_{lost}=T_{\sigma }\Delta S_g$