Numerical Evaluation of Entropy Generation in Isolated Airfoils and Wells Turbines

TL;DR

This paper re-evaluates entropy generation in isolated airfoils and Wells turbines using a refined methodology based on RANS equations, providing more accurate insights into irreversibilities and system losses.

Contribution

It introduces an improved method for estimating entropy generation in turbines and airfoils, addressing limitations of previous simplified approaches.

Findings

More accurate entropy generation estimates compared to prior methods

Verification of results across different flow conditions

Comparison with theoretical values confirms methodology validity

Abstract

In recent years, a number of authors have studied entropy generation in Wells turbines. This is potentially a very interesting topic, as it can provide important insights into the irreversibilities of the system, as well as a methodology for identifying, and possibly minimizing, the main sources of loss. Unfortunately, the approach used in these studies contains some crude simplifications that lead to a severe underestimation of entropy generation and, more importantly, to misleading conclusions. This paper contains a re-examination of the mechanisms for entropy generation in fluid flow, with a particular emphasis on RANS equations. An appropriate methodology for estimating entropy generation in isolated airfoils and Wells turbines is presented. Results are verified for different flow conditions, and a comparison with theoretical values is presented.