Investigation on cycle modes and energy distribution strategies of a novel combined cycle aviation engine

The development of high-performance small aviation engines requires higher power-to-weight ratios, improved fuel efficiency, reduced costs, and sustainable emissions—goals unattainable with standalone piston engines or gas turbines. The combined cycle mode, integrating the piston engine's Dual cycle with the gas turbine's Brayton cycle, offers an innovative approach. This study examines a combined cycle aviation engine (CCAE) and evaluates the effects of various air distribution ratios (α) and air-fuel ratios (λ_br) on performance. The research findings indicate that an α below 20 % is more advantageous for achieving a high power-to-weight ratio. Additionally, a performance simulation model for the CCAE was developed, and a testing platform was designed to validate the accuracy of the simulation model. The study further investigated the impact of different fuel and air distribution strategies on acceleration performance, high-altitude power recovery, economic performance, and emission characteristics. The results suggest that when α = 10 % and λ_br = 15, the time to reach minimum takeoff power decreases by 23.9 %. In addition, HC and PM emissions are significantly reduced, with HC decreasing by over 40 % and PM by more than 30 % compared to the prototype. These findings offer valuable insights for the practical implementation of combined cycle power systems in the aviation sector.