Numerical Simulation Of Flow Field And Performance Research Of Hybrid Propulsion System Based On Aluminum-water Combustion

With the ever-changing international marine state,the performance requirements of naval weapons in the world are increasing.As a conventional naval weapon,torpedoes urgently need to upgrade the energy characteristics to meet today's operational needs.Aluminum powder fuel has high energy density,easy preparation,and environmentally friendly combustion products.If it is used in underwater propulsion technology,the energy characteristics of torpedoes can be significantly improved.In this dissertation,the hybrid propulsion system including water ramjet engine and turbine engine based on aluminum water reaction was studied.Firstly,the initial optimization of aluminum water reaction in the combustion chamber and the calculation of turbine performance under design condition were carried out,and then the aerodynamic performance of the turbine under different working conditions was analyzed.Finally,the overall three-dimensional simulation was carried out to study the combustion characteristics of aluminum water inside the system and the law of two-phase flow gas movement.The thermodynamic calculation of the reaction of aluminum-water was carried out to determine the mass ratio of aluminum and water so that the inlet gas temperature can satisfies the design condition of the turbine.The influence of different parameters on the inner flow field of the chamber was analyzed by changing the second water inlet position and got the optimal the second water inlet position by numerical simulation method.According to the calculated two-phase gas thermodynamic parameters,the onedimensional thermodynamic calculation of the turbine was carried out,and the performance characteristics of the turbine were obtained.The numerical simulation of the turbine under design conditions was carried out.The flow law and energy loss of the two-phase gas in the turbine were analyzed.The calculation results were in good agreement with the theoretical calculation.The numerical simulation method was used to calculate the aerodynamic performance of the turbine under different inlet total pressures and different outlet back pressures.The results showed that the total pressure loss and power of turbine increased with the increase of the expansion ratio.The efficiency increased first and decreased afterwards,reaching the maximum under the design conditions.Finally,the three-dimensional numerical simulation of the overall hybrid propulsion system showed that the reaction rate of aluminum powder particles was related to the reactant concentration and turbulence intensity.Compared with the gas,the particles' temperature lag and speed lag were relatively obvious.After the two-phase flow entered the turbine,shock waves were generated in the blade passages and flow separation was formed,resulting in a large total pressure loss.In this dissertation,the hybrid propulsion system based on aluminum water reaction was studied by numerical simulation.The two-phase flow law and performance characteristics inside the system were obtained,which can provide theoretical guidance for relevant experimental research.