Experimental and numerical analysis of the combustor for a cogeneration system based on the aluminum/water reaction

• Aluminum reaction with water is studied as a technology for hydrogen production.
• A test rig is developed for the analysis of aluminum/water reaction.
• The system is the core component of a cogeneration plant for hydrogen/power production.
• The interaction of liquid aluminum jet and water steam stream is investigated.
• The main capabilities of the injection system are assessed.

The paper focuses on the design of the experimental apparatus aimed at analyzing the performance of the combustion chamber of a cogeneration system based on the reaction of liquid aluminum and water steam.The cogeneration system exploits the heat released by the oxidation of aluminum with water for super-heating the vapor of a steam cycle and simultaneously producing hydrogen. The only by-product is alumina, which in a closed loop can be recycled back and transformed again into aluminum. Therefore, aluminum is used as an energy carrier to transport the energy from the alumina reduction plant to the location of the proposed system. The water is also used in a closed loop since the amount of water produced employing the hydrogen obtained by the proposed system corresponds to the oxidizing water for the Al/H2O reaction.This study investigates the combustor where the liquid aluminum–steam reaction takes place. In particular, the design of the combustion chamber and the interaction between the liquid aluminum jet and the water steam flow are evaluated using a numerical and an experimental approach.The test rig is specifically designed for the analysis of the liquid aluminum injection in a slightly super-heated steam stream. The first experiments are carried out to verify the correct behavior of the test rig. Thermography is employed to qualitatively assess the steam entrainment of the liquid aluminum jet.Finally, the experimental measurements are compared with the multi-dimension multi-phase flow simulations in order to estimate the influence of varying operating conditions on the reaction behavior. Further analysis will concern experiments aimed at investigating the reaction efficiency for different aluminum and water steam mass flow rates as well as the effects of the relative fuel/oxidizer speeds.