FEDSM

Dr. D. R. Reddy
Deputy Chief, Propulsion Division
NASA Glenn Research Center (GRC)
Cleveland, Ohio 

FEDSM2017-69576
Plenary Presentation
An Overview of Aerospace Propulsion Research at NASA Glenn Research Center

NASA Glenn Research center is the recognized leader in aerospace propulsion research, advanced technology development and revolutionary system concepts committed to meeting the increasing demand for high performance, and light weight propulsion systems for affordable and safe aviation with environmental compatibility and space transportation needs to reduce travel times as well as increase payload capability for deep space missions. The technologies span a broad range of areas, including air-breathing propulsion, combined cycle propulsion, chemical rocket components and engines, electric and plasma-based propulsion systems, and advanced propulsion concepts for commercial and military aviation as well as in-space propulsion applications. The scope of work includes fundamentals, components, processes, and system interactions. Technologies developed use both experimental and analytical approaches.

Recent technology advancement efforts in gas turbine engines used for aviation propulsion have been focused on achieving significant improvement in performance at the system level with the overall goals of reducing engine weight, fuel burn, emissions, and noise to meet the national challenges in the areas of energy efficiency and environmental compatibility. These goals translate to aggressive designs of all the engine components well beyond the state of the art. Compressors and turbines would need highly loaded turbomachinery resulting in dramatic increase of work absorption and output with high efficiencies as well as adequate stable operability margins. Inlets and nozzles should be able to diffuse and expand the flow in much smaller regions maintaining minimum total pressure losses and satisfying operability, cost, weight, signature, life, and acoustic requirements simultaneously. Combustor designs need to deliver targeted emission reductions through efficient combustion at lower peak temperatures in order to eliminate or significantly reduce NOX, CO2, and unburnt hydrocarbons.

In the area of in-space propulsion, the areas of focus for research and technology development have included advanced chemical propulsion technology aimed at innovative low cost component design and manufacturing; non toxic and advanced propellants; nuclear thermal propulsion (NTP) research, technology and system analysis; electric and plasma based propulsion systems technology aimed at very high specific impulse devices such as ion and hall-effect thrusters, magneto plasmadynamic and pulsed inductive thrusters utilizing electrostatic and electromagnetic acceleration mechanisms; and advanced propulsion concepts to meet the performance and life requirements for deep space missions.

The presentation provides an overview of the current research and technology development activities at NASA Glenn Research Center in the areas mentioned above to enable the future aerospace propulsion system designs to meet the aggressive mission goals.

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Dr. Eric Nielsen
Research Scientist
Computational AeroSciences Branch
NASA Langley Research Center (LaRC)
Hampton, Virginia

FDSM2017-69357
Plenary Presentation
Adjoint-Based Aerodynamic Design of Complex Aerospace Configurations

An overview of twenty years of adjoint-based aerodynamic design research at NASA Langley Research Center is presented. Adjoint-based algorithms provide a powerful tool for efficient sensitivity analysis of complex large-scale computational fluid dynamics (CFD) simulations. Unlike alternative approaches for which computational expense generally scales with the number of design parameters, adjoint techniques yield sensitivity derivatives of a simulation output with respect to all input parameters at the cost of a single additional simulation. With modern large-scale CFD applications often requiring millions of compute hours for a single analysis, the efficiency afforded by adjoint methods is critical in realizing a computationally tractable design optimization capability for such applications.

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ASME Fluids Engineering Award Plenary Lecture

Professor Michael W. Plesniak
Department of Mechanical and Aerospace Engineering
The George Washington University

Studies of Unsteady Flows Inspired by Biomedical Applications

Pulsatile flows, unsteady phenomena, coherent vortical structures, and transitional or turbulent flows at low Reynolds numbers occur in the human body. Examples of pathological blood flow in which unsteadiness, separation and turbulence are important include regurgitant heart valves, stenoses or blockages, stents, and arterial branches and bifurcations. Speech production involves unsteady pulsatile flow and turbulent structures that affect the aeroacoustics and fluid-tissue interaction. The overall goal of our cardiovascular-inspired research program is to understand secondary flow structures in arteries and to assess their potential impact on vascular health and disease progression.  The richness of morphologies and physics of secondary flow vortical structures and their formation and subsequent loss of coherence during deceleration phases suggests implications related to the blood flow in diseased, stented and stent-fractured conditions. The goal of our human phonation research program is to investigate the dynamics of flow past the vocal folds (VF) and the aerodynamic interaction with the VF. Studies are performed under both normal and pathological conditions of speech.  In particular, recent attention has been focused on understanding the role of polyps (growths on the VF) in altering voice quality.  This has led to very fundamental studies of 3D flow separation in pulsatile flows. Our overarching motivation for studying flows relevant to biomedical applications is to facilitate evaluation and design of treatment interventions and for surgical planning, i.e. to enable physicians to assess the outcomes of surgical procedures by using faithful computer simulations.  Such simulations are on the horizon with the advent of increasingly more powerful high performance computing and cyberinfrastructure, but they still lack many of the necessary physical models.

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Freeman Scholar Award Lecture

Professor Sivaramakrishnan-Balachandar
Department of Mechanical and Aerospace Engineering
University of Florida

An Improved Point-Particle Approach That Captures Fully-Resolved Physics Euler-Lagrange point-particle (EL-PP) technique has been increasingly employed for solving particle, droplet and bubble-laden flows. Since flow around the individual particles is not resolved, the accuracy of the technique depends on the fidelity of the force law used for representing the fluid-particle momentum exchange that occurs at the microscale. In the first part of the talk we will discuss the generalized Faxén form of the force law, which allows accurate accounting of the coupling between the flow and the particle even under complex conditions, where the length and time scales of the flow are comparable to those of the particle (such as during shock-particle interaction).

The applicability of the above approach is however still limited to particles of size much smaller than the grid scale and to dilute flows where inter-particle interaction is weak. In the second part of the talk we will discuss recent fundamental developments that begin to ease these limitations. With increasing numerical resolution, as the grid size approaches the particle size, we face the unpleasant prospect of force law becoming less accurate. This is due to the self-induced flow generated at the particle location, which corrupts the estimation of undisturbed flow velocity that is needed in the force evaluation. We will discuss theoretical approached to properly correcting for the self-induced flow. Finally, we will present the pairwise interaction extended point-particle (PIEP) model which rigorously extends the point-particle technique to higher volume fractions. This model systematically accounts for the precise location of all the neighboring particles in computing the hydrodynamic force on each particle. The model assumes pairwise interaction so that the perturbation flow induced by each neighbor can be considered separately and superposed. The generalized Faxén form is then used to quantify the perturbation force due to the presence of the neighbors. The PIEP model predictions are compared against corresponding DNS in a number of test problems.

Bio: S. "Bala" Balachandar got his undergraduate degree in Mechanical Engineering at the Indian Institute of Technology, Madras in 1983 and his MS and PhD in Applied Mathematics and Engineering at Brown University in 1985 and 1989. From 1990 to 2005 he was at the University of Illinois, Urbana-Champaign, in the Department of Theoretical and Applied Mechanics. From 2005 to 2011 he served as the Chairman of the Department of Mechanical and Aerospace Engineering at the University of Florida. Currently he is a distinguished professor at the University of Florida. He is the William F. Powers Professor of Mechanical & Aerospace Engineering and the Director of College of Engineering Institute for Computational Engineering.

Bala received the Francois Naftali Frenkiel Award from American Physical Society (APS) Division of Fluid Dynamics (DFD) in 1996 and the Arnold O. Beckman Award and the University Scholar Award from University of Illinois. He is Fellow of ASME and the American Physical Society Division of Fluid Dynamics. He is currently an editor of the International Journal of Multiphase Flow and the Theoretical and Computational Fluid Dynamics.

He is currently an editor of the International Journal of Multiphase Flow and the Theoretical and Computational Fluid Dynamics.