To shorten the axial length of detonation tube

a practicable way was used by replacing straight detonation tube with a curve one. A series of two-dimensional numerical simulations were performed in U-bend square tubes

and the effect laws of ignition position

ignition energy

inner radius of bend-section on formation and diffusion of detonation wave were studied. The simulation results show that the deflagration to detonation transition (DDT) time reduces with the increase of inner radius of bend-section; when the inner radius of bend-section is the maximum

the DDT distance is the shortest; the increasing ignition energy means the increasing shock wave strength in detonation tube and the decreasing DDT time; when the ignition position is set at 300mm after the inlet of the detonation tube

the peak pressure of detonation wave is the highest

and the DDT time is the shortest.