As hypersonic vehicles become integrated into the military and commercial applications, often designers are having to balance a myriad of competing design requirements. For simplicity and reliability, fixed geometric configurations are often chosen to optimize performance at a given cruise condition. This results in a desire to improve inlet and isolator performance by optimizing compression ratio and efficiency at the cruise condition which can easily result in less robust operation margins at other conditions such as scramjet engine takeover (end of boost). Specifically, within the system design cycle, the need for improved inlet-isolator performance is often met with the increase in inlet contraction ratio and the elongation of the inlet-isolator system when there is space available. Consequently, design changes in the pursuit of performance and mass-capture gains often make inlet starting and operation under high back pressure more challenging at engine takeover conditions. To facilitate engine starting flow control approaches are generally required and have traditionally included large amounts of bleed air. In fulfilment of this SBIR, GHI will develop, integrate, and determine the efficacy of variety of proposed flow control methodologies with the goal of increasing inlet system recovery and operability while decreasing inlet-isolator length and mitigating flow distortion and other losses. GHI is proposing to work with the Navy to select a suitable inlet design relevant to a desire Navy mission. Several flow control strategies will be investigated to determine improved isolator performance or reduce required isolator lengths. These strategies will also be investigated within the context of optimally locating the required intervention for best performance regarding a variety of competing design goals. A high-level performance requirement and mission sizing would be performed for the vehicle in conjunction with high fidelity numerical simulations of the proposed flow interventions to inform improved vehicle design. Using this new design, a series of wind tunnel experiments would be conducted to produce validation data for the numerical methods that were developed. These results would then be utilized to scale up the technology to prepare for relevant flight scale wind tunnel experiments and real-world testing.
Benefit: GoHypersonic envisions the benefit of this research and development will support government, academic, and industry partners. A successful SBIR would require significant development of computational techniques that have applicability beyond the current development effort. Given the significant number of institutions that utilize a similar toolset to GHI, an expansion of capability in utilizing optimization techniques and expanding a design and analysis toolset would prove useful to many. The ability to perform robust high fidelity scramjet flow path analysis without large upfront development would be helpful to many government and industry partners. Furthermore, if additional analysis toolset development were required for a candidate vehicle GHI could easily support those efforts. Demonstrated efficacy of the flow control mechanism would prove allow for application to other vehicles and there are many in the hypersonics community that would be interested in pursuing partnerships. GHI has significant experience in systems design and subsequent integration into flight vehicles and offering engineering and analysis would be a potential commercial application. As the number of operational hypersonic vehicles in the military and commercial space increase, the ability to expand or provide additional operability to inlets is attractive.
Keywords: Optimal Scramjet Design, Optimal Scramjet Design, Hypersonics, inlet, weapons, Passive Flow Control, isolator
