Design of Hypersonic Variable Cycle Turboramjet Engine Based on Hydrogen Fuel Aiming at 2060 Carbon Neutralization

In order to tackle the global warming problems caused by carbon dioxide and respond to the urgent need for energy saving and emission reduction, the ecological footprint in the space field should be drastically reduced to finally realize the zero-carbon emission flight. Considering the characteristics of high calorific value, wide flammability and zero carbon emissions, hydrogen shows great potential advantages in powering aircraft. This paper develops a hypersonic turboramjet model using hydrogen to replace traditional kerosene. The design target is to realize the hypersonic flight with Mach number 6.0 and high altitude ranging from 25 to 40 km. Based on the over-under turboramjet configuration, a robust boundary approaching design method was proposed and implemented. The technology level in 2060 was predicted and exploited to minimize the specific fuel consumption (SFC). To achieve the lightweight engine architecture, the light-density and temperature-resistant ceramic matrix composite (CMC) turbine and micromix combustor were employed. The corresponding cycle parameters, net thrust, fuel consumption and engine weight were obtained. The findings showed that the optimum switch point for the turbojet and ramjet was at Mach number 3.0 and altitude 25 km where the turbojet pressure ratio was 18. The feasibility check of the turboramjet proved good reliability with the aerodynamic loading and strength capability within the limitations. The utilization of hydrogen could dramatically lower SFC by more than 60% relative to the kerosene turboramjet. This engine features a lightweight, clean and economical aerospace power plant, which can efficiently complete the flight envelope mission, prolong the flight range and broaden the combat radius.