Study of the flow characteristics, pressure drop and augmentation of heat performance in a horizontal pipe with and without twisted tape inserts

Abstract

Heat exchangers are utilised in many heating and cooling processes within different industries. The effectiveness of the heat exchanger is partly dependent on the flow and heat transfer characteristics of the fluid inside the heat exchangers. This study focus on analysing the flow and heat transfer characteristics of water within a straight circular pipe with twisted-tape inserts. For this study, a 3D numerical model for straight circular pipe 11.08 mm diameter and 1920 mm length was developed with water as the heat transfer fluid and validated using published experimental data. The simulation was done for a range of Reynolds numbers (1500–24,000) and four twisted-tape inserts with different widths (1, 2, 2.5 and 3 mm). The results revealed that the twisted-tape inserts induced noticeable swirling of the flow inside the pipe. The swirling was more prominent with the wider twisted-tape geometry (1 mm × 3 mm). The pressure drop along the pipe also increased with the use of the inserts. The numerical results also gave significant improvement in the heat transfer with the use of the twisted-tape inserts. The enhancements achieved with the twisted-tape inserts was between 23% and 29% with higher enhancement achieved with the wider twisted-tape inserts.

Keywords

• Heat transfer enhancement
• Twisted-tape inserts
• Flow characteristics
• Turbulent flow
• 3D horizontal circular pipe