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The Open National Combustion Code (OpenNCC) is applied to the simulation of a realisticcombustor configuration [Energy Efficient Engine (E(exp. 3))] in order to investigate the unsteady flow fields inside the combustor and around the first stage stator of a high pressure turbine (HPT). We consider one-twelfth (24 degrees) of the full annular E(exp. 3) combustor with three different geometries of the combustor exit: one without the vane, and two others with the vane set at different relative positions in relation to the fuel nozzle (clocking). Although it is common to take the exit flow profiles obtained by separately simulating the combustor and then feed it as the inflow profile when modeling the HPT, our studies show that the unsteady flow fields are influenced by the presence of the vane as well as clocking. More importantly, the characteristics (e.g., distribution and strength) of the high temperature spots (i.e., hot-streaks) appearing on the vane significantly alters. This indicates the importance of simultaneously modeling both the combustor and the HPT to understand the mechanics of the unsteady formulation of hot-streaks.

We propose and analyze the use of a Bayesian approach for the investigation of missing reactions, considering both modeling and experimental uncertainties. The main idea is the use of two calibration data sets: one is experimental and the other is articially designed

The objective in this paper is to analyze some stochastic models for estimating the ionization reaction rate constant of atomic Nitrogen (N+e^-->N^++2e^-). Parameters of the models are identified by means of Bayesian inference using spatially resolved absolute radiance data obtained from the Electric Arc Shock Tube (EAST) wind-tunnel. The proposed methodology accounts for uncertainties in the model parameters as well as physical model inadequacies, providing estimates of the rate constant that reflect both types of uncertainties. We present four different probabilistic models by varying the error structure (either additive or multiplicative) and by choosing different descriptions of the statistical correlation among data points. In order to assess the validity of our methodology, we first present some calibration results obtained with manufactured data and then proceed by using experimental data collected at EAST experimental facility. In order to simulate the radiative signature emitted in the shock-heated air plasma, we use a one-dimensional flow solver with Park's two-temperature model that simulates non-equilibrium effects. We also discuss the implications of the choice of the stochastic model on the estimation of the reaction rate and its uncertainties. Our analysis shows that the stochastic models based on correlated multiplicative errors are the most plausible models among the four models proposed in this study. The rate of the atomic Nitrogen ionization is found to be (6.2+/-3.3)x10^1^1cm^3mol^-^1s^-^1 at 10,000K.

Kenji Miki∗, Marco Panesi∗, Ernesto E. Prudencio†, Andre Maurente∗, Sai Hung Cheung∗, Jeremy Jagodzinski∗, David Goldstein‡, Serge Prudhomme§, Karl Schulz¶, Chris Simmons‖, James Strand∗∗ , and Philip Varghese†† Center for Predictive Engineering and Computational Sciences (PECOS), Institute for Computational Engineering and Sciences (ICES), The University of Texas at Austin, 1 University Station C0200, Austin, Texas 78712, USA

of scramjet engines, it is necessary to develop new techniques to increase the mixing and flameholding properties at high Mach numbers of current scramjet designs. This paper investigates the high-temperature chemistry and plasmadynamic eects of a discharge arc in a supersonic shear layer. This is the first step in developing a clear understanding of the physics governing flameholding and mixing in scramjets. Magnetohydrodyamic source terms are included in fluid conservation equations and the electron energy conservation equation is added to the solution set. This allows the modeling of additional terms such as Ohmic heating, ionization energy loss, and heat transfer through electron and heavy particle collision. The large-eddy simulation (LES) equations are derived and closed using a local-dynamic kinetic energy model (LDKM). The magnetohydrodynamic LES equations are solved numerically under the low Magnetic Reynolds assumption, and the magnetohydrodynamic subgrid terms are ignored in the current work, although these assumptions can be easily relaxed. A chemical kinetic model proposed by Chul Park, which uses 11 species and 51 reactions, simulates the radical distributions in the vicinity of the plasma. Results for a plasma source in a supersonic flow are discussed in this paper.

A Local Dynamic Kinetic Energy Model (LDKM) for large-eddy simulation (LES) of magnetohydrodynamicis (MHD) turbulence is proposed. The proposed MHD turbulence model evaluates all model coecients locally and dynamically without any ad hoc averaging. This model does not assume low magnetic Reynolds numbers. The turbulent residual-helicity eect ( -eect) appearing in the magnetic induction equation is successfully modeled and consistently remains a pseudo-scalar. This paper uses the MHD-LDKM LES model to compute high-Re decaying isotropic turbulence in a magnetic field. A decay model is used for validation. It is observed that the energy spectrum follows a k 5/3 law in DNS and LDKM results. For further validation, the long time behavior of ideal invariants: energy (E), cross helicity (Hc), and magnetic helicity (Hm) are examined. The expected selective decay is observed when Hc is finite. This MHD LDKM model is applicable to wide variety of high/low magnetic Reynolds number applications.

1 Abstract A combined experimental-numerical study is underway to validate a new large-eddy simulation (LES) for supersonic combustion studies. Experimental data on fuel-air mixing is being obtained at Georgia Tech and University of Florida while supersonic combustion is being investigated at University of Florida. The results obtained in the first year’s effort are summarized in this paper with particular emphasis on the LES model development and validation.