Experimental investigation of entropy generation in a pipe heat exchanger with turbulence generator inside and on the outside

Abstract

The thermal performance of a pipe heat exchanger can be improved with the use of turbulator inserts. This is accompanied with a drop in pressure because of secondary swirl flow creation in the exchanger. A number of experiments were performed to find the entropy formation with twisted tape inserts inside a tube and helical ribs over the outside of a tube heat exchanger. A counter flow system with water being used as a working fluid was used. The simple pipe validation was performed using standard correlations, and the findings were found to be within an acceptable range. As the Reynolds number was increased, it was discovered that the irreversibility of heat transfer gets increased. As the twist ratio falls, the entropy created due to friction increased. The Bejan number demonstrates that the formation of entropy is mostly attributable to the irreversibility of heat transport rather than the irreversibility of fluid friction. A Bejan value close to one suggests that there is a significant irreversibility of heat transfer in all instances.

Keywords

• Entropy generation
• Heat transfer
• Friction factor
• Bejan number
• Helical tape