Investigation of heat transfer and drag characteristics of water flow with a polymer additive

• Main Author: Yeo, Aaren Yuqi
• Other Authors: Leong Kai Choong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/159168
• Institution: Nanyang Technological University

The discovery of drag reduction in turbulent flow with addition of drag reducing additives was made by Toms. Since then, many studies have been done to further this field of research. Drag reduction as a phenomenon would mean an increase flow rate or a decrease in pressure drop in the flow. This can happen with minute amounts of additives added into the system. As such, addition of drag reducing additives would be a cost-efficient way to decrease the pumping energy required for a given system, resulting in massive savings in pumping costs, with notable applications being in transportation of crude oil over large distances. There are three types of drag reducing additives being studied now, with surfactant additives being studied for the application in recirculating systems. Surfactants are said to be suited for this application as it can self-repair its structure after being subjected to the high shear stresses due to pumps in the system. However, the structure responsible for the drag reduction is also responsible for heat transfer reduction. This poses an issue with applications such as district heating and cooling, where at some point, the increase in heating costs would exceed the savings in pumping costs. While there have been studies done to restore the heat transfer capabilities, surfactant additives also suffer from the disadvantage which is being not environmentally friendly, where improper disposal will cause great harm to the environment. This report looks to investigate the effects of addition of an alternative drag reducing additive in turbulent flow, a polymer named Polyethylene oxide (PEO). This is done with concentrations of PEO at 15 ppm, 30 ppm, and 45 ppm, with varying Reynolds number. A maximum drag reduction of 9.32%, and a maximum heat transfer reduction of 42.4% was achieved.