Research, Analyze and Innovation for Verneuil’s crystal growth Burners – RAInBOV

RSA Le RUBIS SA is the European leader regarding synthetic sapphire manufacturing. For over eighty years, the French manufacturer has been adapting to ever more competitive and changing markets and to increasing quality requirements from its historical clients, from the watch industry to the optical and electronic civil and military industries.
This leadership is built on the mastery of one of the sapphire’s manufacturing process. This crystal growth technology is based on an oxygen/hydrogen diffusion flame whose high temperature allows the fusion of alumina particles, of which is mostly made sapphire.

At present, RSA Le RUBIS SA is facing two main issues :
- Reducing its production costs while improving the quality of its crystals in order to stay competitive against worldwide competitors who are using new crystal growth technologies and who are developing rapidly.
- Finding a fuel other than hydrogen, its historical fuel, in order to adapt to the evolution of its sourcing.

To deal with those challenges which are a potential threat to the firm’s mid-term future, RSA Le RUBIS has decided to increase its efforts in terms of research and development: the CETHIL laboratory was chosen to explore all the possible outcomes regarding those two issues.
The Centre d’Energétique et de Thermique de Lyon (CETHIL) is a Mixed Research Unite (UMR 5008) between the CNRS, the engineering school INSA Lyon and the UCBL: its reputation regarding combustion and more specifically thermic transfers in reactive flow is renowned.
Previous exploratory studies have allowed both partners to identify two priority research fields:
- The improvement of the historical process which uses hydrogen through a global approach of what causes the variability of the crystal’s quality at first, then through a focus on the most influent mechanisms (presence of water vapour in the fuel, thermal confinement of the burner, ..) on the process.
- The design of an innovative extension of this process to other fuels of different nature (natural gas, biogas, synthetic gas).

The scientific problematics which are to be developed are numerous and their implications extend beyond this collaboration. It concerns the technological challenges about industrial burners:
- The stabilization of non-premixed flames.
- The flexibility of burners concerning the use of new types of fuels.
- The anticipation and control of the constraints created by the reactive flow’s modification (thermic constraints on the burner, soot and pollutant gas production).
LabCom RAInBOV will allow the necessary means to be called up, will provide a mid-term visibility and will galvanise the collaboration between RSA Le RUBIS and the CETHIL. This shared laboratory demonstrates both firms’ will to build a long-term synergy. This synergy supports RSA Le RUBIS’s innovation strategy and also broadens the CETHIL’s own research area in order to respond to scientific and technological problematics which are linked to the local industrial fabric.