CARNOT CYCLE WITH EXTERNAL AND INTERNAL IRREVERSIBILITIES ANALYZED IN THERMODYNAMICS WITH FINITE SPEED WITH THE DIRECT METHOD

A Carnot engine operating on a closed cycle and having both external and internal irreversibilities is analyzed. The internal irreversibilities are caused by losses generate by finite piston speed and the external irreversibilities are caused by heat transfer through a temperature difference. The irreversible Carnot cycle is displayed on a original T-S property coordinates in a manner that accurately illustrates the lost work (Exergy losses) due to the irreversibilities (internal and external). A method for calculating the effect of the piston speed on the internal irreversibilities of Carnot cycle is developed and an example of the results is shown for a range of values of cycle high temperature (2000 K). Using the results of this example, the optimal Carnot engine efficiency is determined as a function of piston speed. The example is extended to include the determination of the optimal system temperature for Maximum Carnot engine power over a range of piston speeds.