Experimental and numerical analysis of a liquid aluminium injector for an Al-H2O based hydrogen production system

This paper investigates pressurised injection system for liquid aluminium for a cogeneration system based on the Al–H2O reaction. The reaction produces hydrogen and heat which is used for super-heating vapour for a steam cycle. The aluminium combustion with water generates also alumina as a byproduct; the aluminium oxide can be recycled and transformed back to aluminium. Thus, aluminium can be exploited as energy carrier in order to transport energy from the alumina recycling plant to the place where the cogeneration system is located. The water is also used in a closed loop; indeed, the amount of water produced employing the hydrogen obtained by the proposed system corresponds to the oxidizing water for the Al/H2O reaction. The development of a specific test rig designed for investigating the liquid aluminium injection is presented in this research study. The injector nozzle is investigated by means of numerical thermal and structural analysis. The calculations are compared and validated against the experimental measurements carried out on ad-hoc developed test rig. A good agreement between the numerical results and the experimental values is found and the new design of the nozzle is devised.