Porous materials are prevalent in both nature and industry. In industry, heat and mass transfer processes often require porous materials. Characterizing the flow and heat transfer facilitates the design of optimal geometries to meet the required performance, such as pressure drop, heat transfer or mass transfer rates. The often-random nature of porous materials hinders control of the geometry. Experiments or simulations can be employed to understand the fluid flow through porous structures. Magnetic resonance imaging (MRI) offers a range of techniques to determine flow and heat transfer and provide validation of simulations.

This thesis aims to develop methods to characterize flow and heat transfer through an ordered porous material based on triply periodic minimal surfaces (TPMS). Additive manufacturing was used to generate a range of different TPMS structures. Initial investigations focused on determining the ability to produce the desired structure accurately and the effects of changing structure on the pressure drop. The pressure drop showed that for aspect ratios as small as 2.1, no wall effects were present, and the transition between laminar and turbulent flow occurred between Reynolds numbers of 60 and 600. Then, the validation of MRI sequences to investigate both velocity and temperature was conducted. First, a sequence to measure spatially resolved velocities was implemented on a commercially available low-field MRI machine. Furthermore, the flow field mapped by the sequence was validated inside a straight tube and later TPMS with volumetric flow rate discrepancies of 6% in both. Second, temperature measurements based on the proton resonance frequency method (PRF) were validated for a high-field MRI machine. The implementation involved a flow compensated spin echo sequence, which sampled both positive and negative times relative to the spin echo centre and detected temperature changes of less than 1°C. Finally, by combining velocity and temperature maps on a high-field MRI machine, the heat transfer and fluid flow were measured for the first time inside a TPMS structure. From the velocity and temperature maps, the local geometry was shown to cause variations in local temperatures and velocity. Comparison with an available numerical simulation highlighted the consistency between flow fields while isolating a potential discrepancy in thermal flow. These maps demonstrated the potential for MRI to characterize both the heat and flow inside a TPMS structure and the potential to discover previously unknown features.