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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Computational Analyses of Complex Flows with Chemical Reactions

January 2012 (has links)
abstract: The heat and mass transfer phenomena in micro-scale for the mass transfer phenomena on drug in cylindrical matrix system, the simulation of oxygen/drug diffusion in a three dimensional capillary network, and a reduced chemical kinetic modeling of gas turbine combustion for Jet propellant-10 have been studied numerically. For the numerical analysis of the mass transfer phenomena on drug in cylindrical matrix system, the governing equations are derived from the cylindrical matrix systems, Krogh cylinder model, which modeling system is comprised of a capillary to a surrounding cylinder tissue along with the arterial distance to veins. ADI (Alternative Direction Implicit) scheme and Thomas algorithm are applied to solve the nonlinear partial differential equations (PDEs). This study shows that the important factors which have an effect on the drug penetration depth to the tissue are the mass diffusivity and the consumption of relevant species during the time allowed for diffusion to the brain tissue. Also, a computational fluid dynamics (CFD) model has been developed to simulate the blood flow and oxygen/drug diffusion in a three dimensional capillary network, which are satisfied in the physiological range of a typical capillary. A three dimensional geometry has been constructed to replicate the one studied by Secomb et al. (2000), and the computational framework features a non-Newtonian viscosity model for blood, the oxygen transport model including in oxygen-hemoglobin dissociation and wall flux due to tissue absorption, as well as an ability to study the diffusion of drugs and other materials in the capillary streams. Finally, a chemical kinetic mechanism of JP-10 has been compiled and validated for a wide range of combustion regimes, covering pressures of 1atm to 40atm with temperature ranges of 1,200 K - 1,700 K, which is being studied as a possible Jet propellant for the Pulse Detonation Engine (PDE) and other high-speed flight applications such as hypersonic missiles. The comprehensive skeletal mechanism consists of 58 species and 315 reactions including in CPD, Benzene formation process by the theory for polycyclic aromatic hydrocarbons (PAH) and soot formation process on the constant volume combustor, premixed flame characteristics. / Dissertation/Thesis / Ph.D. Aerospace Engineering 2012
2

Thermal Decomposition Of Haloethanols And Ignition Of JP-10

Chakravarty, Harish Kumar 08 1900 (has links) (PDF)
In this thesis, the thermal decomposition investigation of haloethanols namely 2-chloroethanol and 2-bromoethanol are reported both experimental and theoretical. Computational calculation of enthalpy of formation haloethanols using isodesmic and atomization reactions has also been reported. Finally, the chemistry of JP-10 ignition has also been investigated using shock tube. Chapter 1 gives a brief introduction to the experimental shock tube technique. Brief surveys of literature pertinent to haloethanols and JP-10 have also been discussed. The importance of thermal rate coefficient and detection techniques in shock tube chemistry is presented. Details of the theoretical methods used in the determination of thermal rate coefficients have been described at the end of the chapter. In Chapter 2, I have discussed experimental methods used in carrying out this work. The details of the experimental shock tube set-up employed in this work have been elaborated in this chapter. Kinetic simulations performed to understand the mechanism of chemical transformation of haloethanols at high temperature have also been presented. In chapter 3, thermal decomposition results obtained for 2-chloroethanol have been described. The kinetic data have been obtained in the temperature range of 930-1100 K behind the reflected shock wave in a shock tube. Analyses of pre and post shock mixture using FT-IR and gas chromatographic techniques are presented. Chemical kinetic simulation performed to simulate the product distribution is presented. The reduced kinetic model has also been presented which was obtained using the sensitivity analysis and was validated by comparison to the shock tube measurements. The details of the β-substitution effect have been shown. The kinetic parameters of the unimolecular elimination of HCl and H2O have been presented both experimentally and theoretically. Theoretical results were obtained by transition state theory using quantum chemistry calculations HF, MP2 (FULL) and B3LYP/6-311++G** level of theory. The details of intrinsic reaction coordinate calculation and potential energy surface calculations have also been described. These experimental and theoretical results suggest that the rate of HCl elimination is faster than that of H2O and HOCl elimination reaction. In chapter 4, I have reported thermal decomposition results obtained for 2-bromoethanol. The kinetic data have been obtained in the temperature range of 910-1102 K behind the reflected shock wave in a shock tube. Analyses of pre and post shock mixture using FT-IR and gas chromatographic techniques are discussed. Chemical kinetic simulation performed to simulate the product distribution is presented. The details of the β-substitution effect are explained. Both experimental and theoretical kinetic parameters of the unimolecular elimination of HBr and H2O have been presented. Theoretical results were obtained by transition state theory using quantum chemistry calculations at the HF, MP2 (FULL) and B3LYP/6-311++G** level of theory. The intrinsic reaction coordinate calculation and potential energy surface have been investigated in details. From this experimental and theoretical studies, it has been concluded that the rate of HBr elimination much faster than that of H2O. However, the experiments show that the rate of HOBr elimination is faster than that of the H2O. In chapter 5, I have reported the computational calculation of enthalpy of formation of haloethanols. The enthalpy of formation of haloethanols of the general formula XC2H4OH were calculated by the HF, MP2, B3LYP, G2, G3, G2MP2, G3B3, G3MP2B3, CBS-Q, CBS-QB3 and CCSD/cc-pVDZ level of theories applying isodesmic and atomization reactions. Results obtained using the Benson’s group and bond additivity methods have also been described at 298.15 K and at 1 atm in the gaseous state. In chapter 6, ignition delay measurement on neat jet propellent-10 (JP-10) and JP-10 + Triethyl amine (TEA) mixture have been reported. The JP-10 (Exo-tetrahydrodicyclopentadiene, C10H16) ignition delay times were measured behind a single pulse reflected shock wave in a shock tube. Experiments were performed over high temperature, high pressure, and three equivalence ratio and for different composition. It has been shown that the TEA can reduce the ignition delay of JP-10. A higher level quantum chemistry calculation has also been presented that were performed to obtain the bond dissociation energies of C-H bonds in JP-10. Chapter7 is the concluding chapter where the main work done in this thesis is summarized and future direction is presented.

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