Multi-Objective Optimisation of Heat Transfer Elements within A Rotary Regenerative Heater

Abstract

In the current climate change crisis, power generation and other large emission industries are under pressure to improve efficiency and cut emissions. Rotary regenerative heaters provide a way to recycle heat from exhaust gas, greatly improving efficiency in boiler heating, emissions treatment, and other areas. Modifying the shape of storage plates within the rotary heater can augment heat transfer whilst retaining flow pressure, allowing for more efficient heat recycling. This study uses Computational Fluid Dynamics (CFD) to perform multi-objective optimisation on a common style of element plate. Pitch and radius of the Flat-Notched-Crossed style element plate were varied to measure the effect on heat transfer and pressure drop characteristics. It was found that both variables significantly affected the performance of the element. Further analysis showed that vortex generation and turbulent mixing were the main source of increased heat transfer and strategically controlling the vortical flow structure improved pressure retention through the part. While there is a general consensus that a larger surface area facilitates increased heat transfer, this study concludes that vorticity and turbulence control are significant factors to the performance of the element design.