Effects Of Sidewall On The Performance Of 2-d Supersonic Inlet

As an important component of ramjet, the supersonic inlet's performance can make tremendous impact on the engine behavior. Across a wide Mach number range, the inlet should always has excellent property such as good starting characteristics, high air flow capture coefficient, high total pressure recovery coefficient, good exit flow field and great capacity to resist high-pressure from the combustion (resistance to anti-pressure capability) to meet the ramjet engine's requirement. These properties are closely related with the inlet geometry.In this paper, effects of the sidewall on the 2-D supersonic inlet performance were investigated through numerical simulation and wind tunnel tests. Firstly, flow field around the inlet head and the flow capture characteristic of two inlets (Model A and Model B) with different sidewall configurations were studied. The Model A has a much better overall performance than Model B in most working conditions, in considerations of flow capture coefficient, resistance to anti-pressure capability and drag coefficient from the perspective of inlet. Secondly, with Model A as a base, the performance of inlets with sidewalls on different locations (degree of sidewall shade) under different Mach number and sideslip angle were studied. Finally, for a simple single-ramp inlet with rectangle intersection, numerical simulation and wind tunnel test were conducted. The performance of the inlet and the pressure distribution with different sidewall shade were obtained under the conditions of sideslip or not. The investigations indicate that:1. With the decrease of degree of sidewall shade, the flow capture coefficient will decline, the external drag and additional drag will increase, the cowl drag is almost constant.2. For the inlet with smaller degree of sidewall shade, the flow coefficient and total pressure recovery are not sensitive to the sideslip angle.3. Thanks to the overflow of the forward-swept sidewall inlet, the separate region on the top wall generated due to the forward transmission of the back-pressure can escape from both sides, and the bow shock would not likely to form, so that the inlet would have a wider sub-critical range and the starting performance of the inlet will be improved.4. The inlet with smaller degree of sidewall shade has a lower back pressure limit, and would get into unstart status easier. So it is recommended to modify the compression ramp according to the degree of sidewall shade, after the 2-D design.5. The study on the single ramp inlet with different degree of sidewall shade has indicated that numerical simulation results are basically consistent with wind tunnel test results. For the inlet with smaller degree of sidewall shade, the overflow sidewall installed on both sides of the top wall can make both the flow coefficient and the total pressure recovery coefficient increased, while improving the sideslip performance significantly.