A series of single detonation experiments were conducted to study the performance of acetylene-air mixtures in square detonation tube.The ion-probes and pressure transducers were utilized to measure the flame velocity and pressure in the tube

respectively.The process of shock-flame interactions was analyzed through different triggering times between ion-probes and pressure transducers.The results indicate that the compression wave occurs always in front of flame without detonation in the smooth tube.With introduction of detonation tube of BR=0.4

detonation occurs in the tube;the flame is in front of shock within the obstacle section

or reversely outside of obstacle section.