Effect of a wavy-type combustion chamber on fuel–air mixing and power performance of an aviation piston engine

A new wavy-type combustion chamber was designed to solve the problems of difficult atomization and poor combustion stability of aviation kerosene. The effects of structural parameters of the wavy-type combustion chamber on fuel–air mixing and power performance of the aviation kerosene direct-injection piston engine at 5500 rpm and full-load cruise were systematically studied. The results show that in-cylinder maximum turbulent kinetic energy (TKE), explosion pressure, and heat release rate first rise then decline with increasing central boss depth, with Configuration A3 (2.65 mm) as the optimal design. In contrast to the poorest-performing A1, A3 delivers 2.9% higher TKE, 15.8% greater maximum explosion pressure, and 17.3% enhanced maximum heat release rate, with the maximum knock factor dropping to 2.5 at 1 °CA after top dead center (significant knock suppression). Analogously, the three parameters follow the same trend with increasing side boss depth, with B3 (3.3 mm) optimal. In contrast to B1, B3 achieves 3.2% higher maximum TKE, 15.8% greater maximum explosion pressure, 19.3% enhanced maximum heat release rate, and a knock factor of 3.0 (effective knock mitigation). The wavy-type combustion chamber attains optimal performance with 2.65 mm central boss and 3.3 mm side boss, outperforming the open-type by 8.6% in maximum explosion pressure and 2.6% in maximum heat release rate. The design and research of the wavy-type combustion chamber contributes to improving the combustion process of the engine and further enhancing the overall performance of the engine.