Modeling of Recombination in Hypersonic Flows: A Combined Theoretical and Experimental Approach
Abstract
The development of hypersonic weapons, frequently noted as a game-changing capability in military superiority, critically relies on the availability of computationally efficient and accurate models for the description of non-equilibrium flows. This proposal aims to construct a reduced-order model for the description of recombining flows. The importance of an accurate modeling of recombination is twofold: i) the study of gas-surface interaction and material response physics, which strongly depend on the state of the gas in correspondence of the vehicle surface; ii) for the characterization of the free-stream in hypersonic test facilities, where non-equilibrium effects ensue as a result of the rapid acceleration of the gas in nozzles. The most physically consistent description of non-equilibrium flows relies on the solution of the master equations for each internal level of the gas particles. However, such a detailed description is impractically expensive. The proposed approach will thus leverage the maximum entropy principle, subject to a series of moment constraints, to reconstruct the logarithm of the distribution function expressed as a power series in internal energy. This approach seeks for an optimal reduced-order representation of the distribution function by grouping together individual energy states that are likely to quickly equilibrate with each other, thus maximizing the accuracy of the reconstruction, and drastically reducing the computational cost. The model constructed will be validated using targeted experimental data collected on an in-house Inductively Coupled Plasma wind tunnel. To this aim, the plasma, generated in the inductor of the plasma facility, is quickly cooled by passing the flow through a water-jacketed brass tube of varying lengths thus tailoring the extent on non-equilibrium. Optical emission spectroscopic and laser absorption techniques will be used to characterize the state of the gas during the recombination.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 21, 2022
- Source ID
- FA95502210039XX0
Entities
People
- Marco Panesi
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Illinois Urbana–Champaign