Improving efficiency and performance of rotary regenerative heaters: computational fluid dynamics-based optimisation of heat transfer plates

White, Jordan (2025) Improving efficiency and performance of rotary regenerative heaters: computational fluid dynamics-based optimisation of heat transfer plates. PhD thesis, University of Glasgow.

Abstract

This study presents a comprehensive investigation into the enhancement of thermal and aerodynamic performance of heat storage plates within rotary regenerative heaters through computational fluid dynamics (CFD) simulations and optimisation techniques.

Rotary regenerative heaters are critical in industrial applications, especially in the power generation and process industries, where they recover waste heat from exhaust gases to enhance overall system efficiency. This process ensures that the industrial applications are as efficient as possible. There is a continual demand to improve thermal performance and efficiency to meet ever-tightening stringent energy efficiency and emission reduction goals.

This PhD project focuses on optimising the aerodynamic and thermodynamic performance of the heat storage plates, or elements, within a rotary regenerative heater using advanced CFD modelling techniques, geometric optimisation, sensitivity analysis and novel innovation of integrating delta winglet vortex generators.

The initial phase involved the development of a CFD model, which was validated against experimental data from a physical test rig. This model successfully predicted the heat transfer and pressure drop performance of 3 different element profile designs, ensuring that the model was robust and accurate, and could therefore be utilised as a “virtual test rig” for continued experimentation.

Subsequently, using the validated CFD model, a geometrical optimisation was performed on the flat notched crossed style element profile. Key geometric parameters – pitch between notches and radius of notches – were altered and tested following a Latin Hypercube design of experiments methodology, and the heat transfer and pressure drop performance was measured at each configuration. A Kriging surrogate model was generated from the input variables and results, and a multi-objective pattern search function found a predicted increase in heat transfer of 7.3% and a reduction in pressure drop of 2.3%. The predicted optimal configuration was tested using the CFD model and it was confirmed that the prediction was accurate to within 1%.

A sensitivity analysis was conducted to ensure the optimised element geometry was suitable for manufacture and to assess the effect of the manufacturing tolerances on the performance of the element. The analysis was conducted using a Box-Behnken design of experiments and kriging surrogate model. The results confirmed that the optimal design maintained an improvement over the baseline design, with the worst-case scenario showing higher performance over the original element geometry, affirming its suitability for manufacture and integration into real-world applications.

To further augment the element performance, vortex generators were studied. Delta winglet type vortex generators were added to the optimised element design. These aerodynamic devices improve performance by generating longitudinal vortex structures that disrupt thermal boundary layers and promote turbulent mixing, leading to enhanced convective heat transfer. The chosen delta winglet configuration involved winglets angled opposed to the notches, with the intention of directing flow towards this area to enhance the existing flow effects generated by the notches. An optimisation scheme was carried out on the winglets, focusing on the length, angle of attack and distance from front of plate variables. A further 1% improvement in both heat transfer and friction factor was established.

The findings highlight the efficacy of combining CFD simulations with optimisation techniques to optimise heat transfer plates, ultimately leading to reasonable enhancements in the efficiency and effectiveness of rotary regenerative heaters.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: T Technology > T Technology (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Vezza, Dr. Marco and White, Dr. Craig
• Date of Award: 2025
• Depositing User: Theses Team
• Unique ID: glathesis:2025-85263
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Aug 2025 12:52
• Last Modified: 14 Aug 2025 12:53
• Thesis DOI: 10.5525/gla.thesis.85263
• URI: https://theses.gla.ac.uk/id/eprint/85263

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