Three-dimensional detonation structures and effects of thermal confinement in a linear channel

This study employs three-dimensional (3D) numerical simulations to investigate the detonation wave propagation in an unwrapped annular combustor configuration, focusing on thermal confinement effects on detonation structures and blast dynamics. The compressible Navier-Stokes equations are solved for stoichiometric kerosene-air mixtures under three distinct wall boundary conditions: (1) adiabatic (uncooled), (2) isothermal at 300 K (representing actively cooled walls), and (3) hybrid adiabatic-isothermal configurations. Results reveal that wall temperature critically governs detonation morphology: adiabatic boundaries produce regular cellular structures via ‘multi-kernel’ formation (intersections of four transverse waves), while cooled walls (300 K) generate stripe-like ‘line-kernel’ (formed through two-wave intersections), accompanied by double-wave structures, increased pressure fluctuations, and unburned fuel pockets. The hybrid case demonstrates asymmetric detonation development, with stable propagation on the adiabatic side contrasting with elongated cells and intensified wave-wall interactions on the cooled side. Quantitative analysis shows that cooled boundaries reduce the detonation wave height compared to adiabatic cases and promote irregular cell sizes due to suppressed boundary layer reactions. These findings present the first systematic evidence of 3D thermal confinement effects on RDW dynamics, revealing a critical trade-off in combustor design: while lower wall temperatures enhance material durability, they compromise combustion efficiency through increased flow unsteadiness and incomplete fuel consumption. The study advances the fundamental understanding of detonation physics in practical thermal gradients and provides actionable insights for optimizing cooling strategies in rotating detonation engines.