Diagnostic Assessment of Detonation-Drivers for Hypervelocity Expansion Tube Ground Testing
Abstract
A significant challenge to advancing national hypersonic flight capabilities is recreating the flight environment in ground tests, including test flow characterization. Only a handful of large-scale facilities capable of reproducing flight velocity and altitude exist in the US. Expansion tubes have recovered favorable interest after Paull and Stalker identified acoustic noise sources that limited the operation of the first facilities from the 1960s. However, a key limitation to facility capability predictions and to flow quality in expansion tube/tunnel operation is the rupture of the primary diaphragm. Typically, 1 to 2 sheets of mm-thick metal across the diameter of a large-scalefacility, primary diaphragm rupture results in departure from ideal facility operation, shot-to-shot variation of burst pressure, and the generation of particulates - or in the worst-case, fragments - that can contaminate the test gas and, propagating at km/s, destroy models.We are building on our expertise in high-enthalpy hypersonic testing and detonation physics to design, build, test, and characterize detonation drivers for expansion facility operation. With this proposal, we request equipment to build on existing capabilities to characterize the gas dynamics of detonation-driven facility operation and quantify the flow quality consisting of timeresolved schlieren imaging of unsteady processes and shock shape, quantitative high-speed imaging of post-shock and free-stream density fields using interferometry, quantitative point measurements of test flow fluctuations using heterodyne detection, and spectroscopicmeasurements of detonation product species.The equipment would enhance three projects conducted by the PIs with DoD support: Development and assessment of detonation-drivers for hypervelocity expansion tube ground testing (ONR.142212141), Spectroscopic measurements and nonequilibrium modeling of highenthalpy air (FA9550-23-1-0446), and Decoding fluid-structuralcoupling during shock-boundary layer interactions acting on compliant surfaces (FA9550-22-10063). In addition, the knowledge gainedwill transfer to national efforts designing shock tunnels and research in detonation-based propulsion systems.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 09, 2024
- Source ID
- N000142512007
Entities
People
- Joseph E. Shepherd
Organizations
- California Institute of Technology
- Office of Naval Research
- United States Navy