Engineering assessment of modeled near-wall thermal-sink effects on early premixed hydrogen-air flame propagation in a semi-open channel

Early premixed hydrogen–air flame propagation in semi-open passages couples front motion, pressure development, induced flow, and localized energy removal. This study uses a prescribed near-wall volumetric thermal-sink region as a controlled reduced-order treatment for screening the response to wall-adjacent energy removal when resolved wall-coupled thermal modeling is outside the study scope. A fixed three-dimensional semi-open channel was evaluated with a baseline case (L0) and three increasing modeled-sink cases (L1–L3). Comparisons used a common 15–30 mm front-position interval defined by T ≥ 1200 K, together with front-ahead pressure and streamwise velocity, remote outlet-layer velocity, and threshold/window sensitivity checks. L1 remained close to L0, whereas L2 was slightly slower. L0 yielded an interval-averaged front speed of 52.94 m s − 1 and a pressure increment of 3.240 kPa; L3 reached 65.22 m s − 1 and 10.758 kPa. At matched front positions, L3 also exhibited the largest increases in front-ahead pressure and streamwise velocity relative to L0, while the remote outlet-layer velocity at a 30 mm front position remained negligible. The observed case ordering therefore supports a non-monotonic coupled pressure–flow response rather than a universal damping sequence. The numerical-assurance checks indicate that the principal L3-over-L0 relative ordering is reasonably robust within the tested settings, but they do not establish fully converged absolute front-speed or pressure values. This conclusion is restricted to the prescribed source-region model, the fixed geometry, and the early front-position interval.