Formulation of a General Collisional Radiative Model for NO to Study Nonequilibrium, Hypersonic Flows
Abstract
Optical flow measurements can provide the most direct tests of our modeling of hypersonic non equilibrium, chemically reacting flows. While surface measurements of temperature, heat flux, and pressure, are certainly important for characterizing the boundary layers and materials interactions, only spectroscopic and laser measurements have the potential to allow us to directly sense the high temperature thermochemical nonequilibrium processes occurring within a flow. The key scientific goal of the proposed research is to use the presence of the nitric oxide molecule formed in hypersonic shocks to test our community s thermochemical nonequilibrium models. To that end, we will formulate and develop a three dimensional, collisional radiative (CR) model for NO that will span multiple flow length scales and opacities encountered around a vehicle and two spectral regions. A number of CR models have been developed for molecular nitrogen, but their emphasis has been on flows at much higher enthalpy where its dissociation is significant and they generally have been applied to stagnation region conditions only. The model will be used to design and interpret experiments of the ultraviolet and infrared spectra of the NO molecule and tunable diode laser absorption spectroscopy in the GALCIT facilities but will be sufficiently general that it can be applied to higher Mach numbers obtainable in larger facilities and in flight. The conditions that will be considered will cover a range of Mach numbers from ?7 20, the range of interest to the Air Force, and primarily geometries and Reynolds numbers that are for steady, laminar flows. A portion of the research will also continue to explore the role of nonequilibrium effects on the time behavior of unsteady flows especially when shock boundary layer interactions become important.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501910342
Entities
People
- Deborah Ann Levin
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Illinois Urbana–Champaign