A Comprehensive Review of High-Performance Cyclone Combustors: Challenges, Mechanisms, and Future Perspectives

Abstract

Cyclone combustors establish chamber-scale strong swirling flow through tangential injection, thereby intensifying fuel-air mixing, hot-product recirculation, particle residence, and ash or slag transport. Their performance is controlled by the coupled effects of inlet momentum, chamber geometry, particle inertia, air staging, wall thermal conditions, and slag-discharge design rather than by swirl intensity alone. This review distinguishes cyclone combustors from conventional swirl burners, cyclone separators, and cyclone gasifiers, and organizes the governing physics using the swirl, Reynolds, Stokes, and Damköhler numbers. It then synthesizes gas-phase recirculation, particle transport, staged solid-fuel conversion, fuel-specific behavior, pollutant formation, ash deposition, and molten-slag tapping. Evidence for pulverized and high-alkali coals, biomass particles, and low-heating-value gases is compared together with the validation requirements of experiments and CFD. The principal unresolved issues are incomplete scale-up criteria, limited high-temperature particle-wall data, weak coupling between combustion and ash/slag models, and inconsistent performance metrics. Engineering progress therefore requires adjustable inlet and air-staging strategies, controlled wall thermal boundaries, experimentally anchored simulation, and multi-objective operating envelopes.