In this numeri cal study, of hydrogen has been presented with strut flat duct length. The combustor has a single fuel injection parallel to the main flow from the base. Finite rate chemistry model with S-A Model have been used for modeling of combustion. In this paper strut at 60 with flat duct length analyzed for without hydrogen injection, with hydrogen injection and hydrogen injection with combustion. The investigation of the shock system produced by a strut injector with subsequent mixing, ignition and flame stabilization showed that the characteristics of the ignition process is considerably different from the shock induced ignition which has been postulated in the past. The ignition is achieved through the irreversible total pressure loss in the wake of Strut due to flat duct length. Flat duct lengths allow the ignition delay to occur before the pressure and temperature is decreased by the expansion. The presence of a boundary layer in the chamber changes the shock system and the ignition conditions in the chamber considerably. Index Term—supersonic combustion, S-A model, finite rate, stagnation temperature, flame speed, Mach number. I. INTRODUCTION Superson ic is the key enabling technology for sustained hypersonic flights. In scramjet engines of current interest, the combustor length is typically of the order of 1 m, and the residence time of the mixture is of the order of Milliseconds. Due to the high flow speed in the chamber, problems arise in the mixing of the reactants, flame anchoring and stability and completion of within the limited combustor length. The flow field in the scramjet combustor is highly complex. It is shown that when the flight speed is low, the kinetic energy of the air is not enough to be used for the optimal compression. Further compression by machines is needed in order to obtain a higher efficiency. For example, a turbojet employs a turbine machine for further compression. When the flight speed is higher than a certain value, the air flow entering a combustor will remain to be after the optimal compression. With a further compression ( i. e. deceleration), the efficiency of the engine will decrease. Therefore the has to take place under the flow condition. This kind of air-breathing engine, which works under hypersonic flight condition, is called the ramjet (Scramjet). The term of supersonic combustion applied here means the