Surface Roughness Effects in TPMS Solar Heat Exchangers: Experiments and CFD
Background
Concentrated solar power (CSP) is becoming an important source of clean energy in Europe’s push to decarbonize electricity. Using air instead of liquids in CSP systems cuts costs, avoids toxic or corrosive fluids, saves water, and works well over a wide temperature range, but it comes at the cost of poor heat transfer.
Adding triply periodic minimal surfaces (TPMS) can further improve air-based heat exchangers. TPMS are intricate, zero-curvature 3D structures that offer a high surface area for heat transfer. They enhance fluid mixing and heat exchange while keeping pressure drops low. Interest in TPMS has grown recently, especially for heat-exchanger applications. Additionally, 3D printing enables fabrication of complex geometries like TPMS but the induced roughness increases pressure drop, thus compromising pumping efficiency. Experimental characterization is important to understand optimum surface characteristics and determine trade-off between heat transfer and pressure drop.
Objective and goals
The primary objective of the thesis is to characterise the surface roughness of TPMS based geometries, integrate it with CFD and validate with experiments.
Methodology
Through a literature review of existing design cases available from the literature of TPMS based heat exchangers involving different heat transfer fluids such as air, initial and boundary conditions are to be identified. Simulations on selected geometries are to be performed using commercial licensed CFD packages such as ANSYS Fluent or likewise.
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Surface roughness characterisation using different available techniques
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A comprehensive CFD study is to be formulated incorporating the measured roughness parameters and quantify its effects on flow and heat transfer.
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Validate CFD with experimental results.
Expected outcomes
This work is anticipated to offer:
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An in-depth knowledge of surface roughness characterisation
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Experience in evaluation of thermo-hydraulic performance of the heat exchanger through turbulence modelling in CFD and experiments.
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Hands-on experience with sensors, controls and 3D printed heat exchangers.
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Potential scope of aiming towards a journal publication in peer reviewed top tier - International Journal of Thermal Sciences, Applied Thermal Engineering, Applied Energy etc.
Deliverables
The main deliverables of the project include:
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Final project report and presentation.
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CAD / CFD models and simulation files with instructions.
Timeline
January 2026 – June 2026 (flexible)
Contact persons
