Flame acceleration and transition to detonation in a pre-/main-chamber combustion system

Numerical simulations are performed to study the mechanism of deflagration detonation transition (DDT) in a pre-/main-chamber combustion system with stoichiometric ethylene–oxygen mixture. A Godunov algorithm, fifth-order space, and third-order time, is used solve fully compressible Navier–Stokes equations on dynamically adapting mesh. single-step, calibrated chemical diffusive model described by Arrhenius kinetics for energy release conservation between fuel product. The two-dimensional simulation shows that laminar flame grows pre-chamber then develops into jet as it passes through orifice. strong shock forms immediately ahead flame, reflecting off walls interacting front. shock–flame interactions crucial development instabilities, which trigger subsequent development. DDT arises due shock-focusing mechanism, where multiple shocks collide at explosive mode analysis (CEMA) criterion developed ignition mode. Preliminary one-dimensional computations propagating fast deflagration, Chapman–Jouguet conducted demonstrate validity CEMA chemical-diffusive model, well determine proper conditioning value diagnostic. indicates initiated can form thermal expansion region front features large positive eigenvalues dominance local autoignition Thus, proposed this provides robust diagnostic identifying autoignition-supported DDT, emergence excessive found be precursor. effect grid size, initial temperature, orifice size evaluated, results show although close-chamber highly stochastic, initiation remains robust.