Numerical Investigation on Performance of Axisymmetric Variable Geometry Scramjet Combustor Equipped with Strut Flame Holder

This manuscript designed an axisymmetric variable geometry scramjet combustor equipped with a strut flame holder to help the combustor work in a wide flight Mach numbers and conducted a series of numerical calculations and experiments to study the performance of the axisymmetric combustor. The characteristics of the combustor under the different flight Mach numbers (2, 4, 6) are discussed by the numerical calculations, and the results testify that the designed combustor can operate in a large range of the flight Mach number. Then the performances of the combustor in high Ma (4 and 6) are studied. The maximum pressure ratio of the combustor under Ma = 6 is about 6.5. With the divergence ratio increasing, the thermal chock of the combustor decreases under the flight Ma = 4. When the flight Ma is 2, and the divergence ratio is 3.2, the combustor can work well with the fuel injected by the center cone and the wall1. However part of the oxygen near the bottom wall can not be ignited, and the flame distribution is uneven. To solve this problem, the multi-wall fuel injected method is taken. With the wall2 fuel added, the mixing efficiency of the fuel increases, and the flame near the bottom wall is established. The results in this study are valuable for the future axisymmetric variable geometry scramjet combustor design and the optimization of combustion distribution uniformity.