基于氢燃料的航空发动机冷却设计研究

In order to optimize the cooling system of hydrogen fuel aero engines,three regenerative cooling schemes were respectively designed for the combustion chamber,nozzle and secondary flow of the turbine,and proposes a coupling solution method for wall thermal environment of hot end components and a calculation method for mass flow of turbine pre-cooled secondary flow suitable for cooling schemes. Based on the analysis of wall heat transfer mechanism,three schemes were compared and evaluated for parameters such as the wall temperature of hot end components,wall heat flow and mass flow rate of turbine pre-cooled secondary flow. The wall temperature and heat flow of the combustion chamber are highly correlated with the main stream temperature,and the peak value appears near the highest point of the main stream temperature. The wall temperature and heat flow of the tail nozzle are affected by both the main flow velocity and temperature,and the peak values appear near the nozzle throat. Scheme 1 has the best cooling effect on the wall of the hot end components,and reduces the maximum temperature of the components by 25.6 K and 212.6 K compared with Scheme 2 and Scheme 3,respectively. Scheme 2 has the best pressure loss control,reducing it by 5.8 kPa and 3.0 kPa respectively compared to the other two schemes. In Scheme 3,the pre-cooling effect of turbine secondary flow is the best,and the mass flow rate decreases by 12.9% and 11.6% compared with Scheme 1 and Scheme 2,respectively. In addition,reducing the initial temperature of the cooling medium or increasing its mass flow rate can enhance the cooling effect and reduce the wall temperature.