High Pressure Single Pulse Shock TubeKenneth Brezinsky, Mechanical and Industrial Engineering

Sponsors: Department of Energy, National Science Foundation, National Aeronautical Space Administration, Office of Naval Research

1) “Shock Tube Study of Thermal Rearrangement of 1,5-Hexadiyne over Wide Temperature and Pressure Regime”, J. Phys. Chem. A 2004, 108, 3406-34152) “A High Pressure Model for the Oxidation of Toluene”, In Press, Proc. Int. Comb. Symp. 30, 2004 3) “High Pressure, High Temperature Oxidation of Toluene”, Combustion and Flame, 139(4), 340-350, 2004 4) “Ethane Oxidation and Pyrolysis from 5 bar to 1000 bar: Experiments and Simulation”.,In Press, International Journal of Chemical Kinetics, 2004 5) “Chemical Kinetic Simulations behind Reflected Shock Waves”, Submitted, Int. J. Chem. Kin., 20056) “Isomeric Product Distributions from the Self Reaction of Propargyl Radicals”, Submitted, J. Phys. Chem. 2005

High Pressure Shock Tube:5 atm < Pressure < 1000 atm800 K < Temperature < 3000 K0.5 ms < time < 2.0 ms

Oxidation of Aromatic Compounds

Soot Formation Chemistry

High Pressure Carbon Monoxide Combustion

Rocket Nozzle Erosion Chemistry

High-Rate Synthesis of Carbon Nanostructures in Oxy-FlamesInvestigators: Lawrence A. Kennedy, MIE; Alexei V. Saveliev, MIE

Prime Grant Support: National Science Foundation, Air Liquide

Problem Statement and Motivation

Technical Approach Key Achievements and Future Goals

• Carbon nanotubes are materials of the future and

synthesis techniques are required for their high quality production at commercial rates

• At present, oxy-flames are the major industrial source of pyrolytic (black) carbon. The development of high-rate synthesis method of carbon nanotubes and carbon nanofibers with controlled structure and morphology will open new horizons stimulating numerous applications requiring large volumes of carbon nanomaterials

• Formation of carbon nanomaterials in opposed flow flames of methane and oxygen enriched air is studied experimentally at various oxygen contents

• A catalytic probe is introduced in the flame media, the products are analyzed using transmission and scanning electron microscopy

• An electric field control of carbon nanomaterial growth is implemented applying combinations of internal and external fields

• A model of carbon nanotube interaction with electric field is developed and applied for the result interpretation

• The method of high-rate synthesis of vertically aligned CNTs with high purity and regularity has been developed

• It is shown experimentally that application of controlled electrostatic potential to a catalytic probe in a flame induces uniform growth of CNT layer of multi-walled nanotubes

• The mechanism of the electric field growth enhancement has been studied experimentally and theoretically. It is found that the major influence of the electric field is related to the polarization alignment of growing nanotubes and charge induced stresses acting on the catalytic particles

~40μm0.34nm

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(b)

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Quantifying the Effects of Fluid Flow Characteristics Near the Nozzle Tip on Diesel Engine Particulate Emissions

• This research is being performed in collaboration with ANL.

• ANL’s Advanced Photon Source (APS) is used to obtain quantitative data of CAT HEUI 315B fuel injector spray.

• State-of-art flame diagnostic tools will be used to obtain in-cylinder images and data of the fuel injector spray and combustion in a CAT single cylinder engine.

• In collaboration with CAT the KIVA-3V code will be developed further and various sub-models, such as for fluid breakup, will be improved.

• Parametric studies will be performed to quantify the effects of fuel injection pressure, tip orifice size and geometry on engine performance, emissions, and particulate formation.

Gravitational Effects on Partially Premixed Flames

• Fire suppression on Earth and in space.• Multi-scale modeling of combustion and

two-phase phenomenon.• Application of advanced CFD methods

using detailed chemistry and transport models to characterize the effective of various fire suppressants..

Simulation of Partially Premixed Flames Burning a Variety of Fuels

• Blending Hydrogen to primary reference fuels to improve combustion and emission characteristics.

• Flame structure, extinction, and emission characteristics of high pressure flames with different fuels [H2, CH4, n-heptane, Synthetic Gas] in engine-like conditions.

• Innovative strategies to reduce combustion-generated pollutants.

• Extensive use of computer graphics and animation.

• Experimental and numerical investigation of structure and emission characteristics of n-heptane flames.

Achievements• Developed comprehensive CFD-based reacting flow codes using

detailed chemistry and transport models for a variety of flames.

• Application of these codes to investigate

structure and emission characteristics of high-pressure partially premixed flames (PPF).

stabilization, liftoff, and blowout of nonpremixed and partially premixed flames in Earth and Space environments.

effect of hydrogen blending with hydrocarbon fuels on flame stability and emissions of NOx, soot, etc.

combustion and emission characteristics of alternative fuels, such as hydrogen, synthetic gas, ethanol, and bio-diesels.

• Develop innovative strategies including partial premixing, alternative fuels, and fuel blending to improve combustor performance and reduce pollutants emissions.

Combustion and Emissions Research Relevant to Practical SystemsS. K. Aggarwal, MIE/UIC; I. K. Puri, Virginia Tech; V. R. Katta, ISSI; D. Longman, ANL.

Primary Sponsors: ANL, NASA, NSF

Large-Scale Simulation of Complex FlowsInvestigators: F. Mashayek, MIE/UIC; D. Kopriva/FSU; G. Lapenta/LANL

Prime Grant Support: ONR, NSF

Problem Statement and Motivation

Technical Approach Key Achievements and Future Goals• Pioneered DNS of evaporating/reacting droplets in compressible flows.

• Developed a multidomain spectral element code for large clusters.

• Developed user-defined functions (UDFs) for implementation of improved models in the CFD package Fluent.

• Developed several new turbulence models for particle/droplet-laden turbulent flows.

• In the process of development of a new LES code with unstructured grid.

• Investigating advanced concepts for liquid fuel combustors based on counter-current shear flow.

The goal of this project is to develop advanced computational techniques for prediction of various particle/droplet-laden turbulent flows without or with chemical reaction. These techniques are implemented to investigate, in particular, liquid-fuel combustors for control of combustion and design of advanced combustors based on a counter-current shear concept. The experimental components are conducted at the University of Minnesota and the University of Maryland.

• Turbulence modeling and simulation• Direct numerical simulation (DNS)• Large-eddy simulation (LES)• Reynolds averaged Navier-Stokes (RANS)

• Droplet modeling• Probability density function (PDF)• Stochastic

• Combustion modeling• PDF• Eddy-breakup• Flamelet

• Flow simulation• Spectral element• Finite volume• Finite element

Droplet Impact on Solid Surfaces Investigator: C. M. Megaridis, Mechanical and Industrial Engineering

Prime Grant Support: Motorola, NASA

Problem Statement and Motivation

Technical Approach Key Achievements and Future Goals

• Droplet impact ubiquitous in nature and relevant to many practical technologies (coatings, adhesives, etc.)

• Spreading/recoiling of droplets impacting on solid surfaces (ranging from wettable to non-wettable) features rich inertial, viscous and capillary phenomena

• Objective is to provide insight into the dynamic behavior of the apparent contact angle and its dependence on contact-line velocity VCL at various degrees of surface wetting

• Perform high-speed imaging of droplet impacts under a variety of conditions

• By correlating the temporal behaviors of contact angle and contact-line speed VCL, the vs. VCL relationship is established

• Common wetting theories are implemented to extract values of microscopic wetting parameters (such as slip length) required to match the experimental data

• Surface wettability has a critical influence on dynamic contact angle behavior

• There is no universal expression to relate contact angle with contact-line speed

• Spreading on non-wettable surfaces indicates that only partial liquid/solid contact is maintained

• The present results offer guidance for numerical or analytical studies, which require the implementation of boundary conditions at the moving contact line