Expanding Hypersonic Flow
Abstract
Flow phenomena in thermochemical equilibrium conditions can be modelled with ease because equilibrium fluid properties depend only on few macroscopic parameters. When equilibrium cannot be attained within the convective time scales of the flow, fluid properties and the rates of transport, reaction and relaxation processes depend on a large number of microscopic parameters. As a consequence, designing and operating hypersonic vehicles and research facilities where non-equilibrium flows exist is expensive and technically challenging. The purpose of this proposal is to study non-equilibrium effects experimentally and numerically under well controlled conditions attained in expanding flows. Non-equilibrium conditions can be established in expanding flows because the rapid drop in temperature accompanying expansion inhibits chemical and energy relaxation processes. Expanding flows are also common in high-speed flight around areas of high surface curvature and have intrinsic engineering value. In the experimental part of this work, spectroscopy and flow measurements will be taken in shock tubes equipped with nozzles designed to obtain well controlled expansion rates and to allow direct optical access to the flow path. In the numerical work, fast and efficient tools will be developed to model expanding flows in shock tubes using measured quantities to directly inform simulations and remove uncertainties. The combination of high-quality measured data and specifically designed simulation tools will lead to improvements in microscopic understanding and continuum-based models for non-equilibrium hypersonic flows. The improvements will result in more realistic approximations for quantities such as recombination and electron capture reactions rates, and other approximations to quantities that depend on detailed distributions of energy levels and velocity.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 22, 2024
- Source ID
- FA86552317043
Entities
People
- Luca Di Mare
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Oxford