Overall, the project contributed to start to address a gap in the literature regarding the optical properties of industrially relevant, non-ideal materials, and in particular the impact of their surface geometry. Specific, WP-wise results and progress beyond the state of the art are listed below.
For WP 1 – Micro-Scale:
- Observation of lack of Lambertian behaviour on industrially relevant rough materials, including significant specularity at increasing incident angles and off-angle specular behaviours.
- Acquisition of a large amount of bi-directional reflectance data and associated samples composition and surface micro-scale topography which are necessary to develop further understanding of the impact of real roughness profiles on the optical properties of industrial materials.
- Development of open-source numerical tools for:
1. The interpretation, correction, analysis and conversion to STL of surface profilometry of rough surfaces with extraction of anisotropic statistical information.
2. The numerical simulation of rough surfaces and bi-directional reflectances via Monte-Carlo Ray Tracing in a general purpose open-source ray-tracer.
3. An open access library to process, analyse and represent of BDRF data.
For WP 2 – Meso-scale:
- First reported additively manufactured surface features on high-temperature materials to modify their optical/radiative properties and successful demonstration that such surface geometries do influence significantly the directional radiative properties.
- Demonstration that simple and widely-used approximations of optical behaviour such as the lambertian or partly specular assumptions cannot accurately reproduce experimental measurements, indicating that the interplay between surface roughness and meso-scale is important.
- Measurement of directional emittance on 3D patterned Inconel materials up to 700 °C.
For WP 3 – Macro-scale:
- Preliminary assessment of the influence of surface optical properties on the effective absorptance of a larger scale device.
Results from activities developed during HEASeRS were disseminated via two oral presentations and three poster presentations in international conferences. Beyond this traditional scientific output, the Researcher communicated the project and the main results to industrial actors in a range of relevant sectors (cement, concentrated solar energy, thermal energy storage, oil and gas, specialty ceramics manufacturing). While it is, at the end of this project, too early to observe socio-economical benefits if the action, the activities developed in HEASeRS constitute the first step in establishing an original research line that will bring societal benefits through decarbonisation when the findings are integrated into the relevant energy and high-temperature process industries.
