Discussion
- Irreversibilities and losses are always associated with the operation of a real mechanical system. The existence of these unwanted effects is accompanied by an increase of entropy as required from the second law. (ex: 3 ?4s isentropic process, 3 ?4, entropy increases for a real process)
- The efficiency of the turbine (ht) will decrease as a result of these losses:
- The isentropic expansion work (Wt)s = h3-h4s is the ideal process and Wt= h3-h4 is the actual work done in a real process
- Similarly, the isentropic pump efficiency can be expressed as
- Because of inefficiency, h2-h1 > (h2-h1)s it required more work to pump and compress the liquid.