Flame-flow interaction during premixed and stratified swirl flame flashback in an annular swirl combustor

The interaction between a propagating flame and the approach flow is critical to the understanding of boundary layer flashback of swirling flames. In this work, I investigated this interaction during flashback using high-speed luminosity imaging and simultaneous three-dimensional particle image velocimetry. The mean axial velocity through the mixing tube is kept at 2.5 m/s while the hydrogen enrichment of the fuel is varied up to 87%. These flashback experiments are conducted at pressures ranging from 1 to 5 atm. To understand the flame-flow interaction physics, I developed a novel analysis methodology for low-turbulence fully-premixed methane-air swirl flame flashback, by stacking the planar flame profiles and three-dimensional velocity data. In the quasi-reconstructed velocity field, the motion of an approaching fluid parcel is analyzed in the frame-of-reference of the propagating flame. For the first time, the role of inertial forces in swirling flame-flow interaction is revealed. Subsequently, I investigated the effect of fuel-air partial premixing on the flashback behavior at atmospheric and elevated pressures. A swirler-based fuel-injection system was used to create fuel-air stratification in the radial direction. For elevated pressure measurements, an optically accessible elevated pressure chamber was designed and constructed to conduct flashback experiments up to 5 atm. The spatial distribution of the equivalence ratio under non-reacting conditions was investigated using planar laser-induced fluorescence with acetone as the fuel tracer. It was observed that fuel-air pockets were distributed across the mixing tube width, although in an average sense, the fuel-air mixture was radially stratified. The global behavior of upstream flame propagation is reported for different levels of hydrogen-enrichment. For stratified hydrogen-rich flashback, the propagation path of the flame changes from the inner wall to outer wall induced by the faster chemistry of stoichiometric mixtures that are frequently present near the outer wall. This behavior of hydrogen-rich flashback persists even at elevated pressures up to 5 atm, although the propagation of the flame occurs as a wide flame tongue as opposed to the acute-tipped flame structures present in the atmospheric cases.Aerospace Engineerin

Hp-spectral Methods for Structural Mechanics and Fluid Dynamics Problems

We consider the usage of higher order spectral element methods for the solution of problems in structures and fluid mechanics areas. In structures applications we study different beam theories, with mixed and displacement based formulations, consider the analysis of plates subject to external loadings, and large deformation analysis of beams with continuum based formulations. Higher order methods alleviate the problems of locking that have plagued finite element method applications to structures, and also provide for spectral accuracy of the solutions. For applications in computational fluid dynamics areas we consider the driven cavity problem with least squares based finite element methods. In the context of higher order methods, efficient techniques need to be devised for the solution of the resulting algebraic systems of equations and we explore the usage of element by element bi-orthogonal conjugate gradient solvers for solving problems effectively along with domain decomposition algorithms for fluid problems. In the context of least squares finite element methods we also explore the usage of Multigrid techniques to obtain faster convergence of the the solutions for the problems of interest. Applications of the traditional Lagrange based finite element methods with the Penalty finite element method are presented for modelling porous media flow problems. Finally, we explore applications to some CFD problems namely, the flow past a cylinder and forward facing step

Ayurvedic Ethics - Part 2

Asian StudiesHindi Urdu FlagshipSouth Asia Institut

Interest in Naturopathy - Part 3

Mr. Dharampal Arora talks about his interest in naturopathy.Asian StudiesHindi Urdu FlagshipSouth Asia Institut

Demographics, Ethics, Awareness

Ethics in medicine is not a new concern. But it has become much more pronounced in modern times. The issues involved may range from right diagnosis and right treatment to the fees charged to patients, and the administration of insurance and medical bills. This issue cuts across all genres of medicine, traditional as well as conventional. In this section we have video clips that inform us about how doctors following different medical systems talk about fees and ethics in their practice.Asian StudiesHindi Urdu FlagshipSouth Asia Institut

Combining Conventional Medicine with Home Remedies

South Asia in general, and India specifically, are regions with immense diversity in culture and language. Because of this conversations about medicine between doctors and patients takes different forms from one region to another. This is especially true when we look at urban, suburban and rural doctor-patient interactions. Added to these is the element of gender. Owing to the somewhat conservative worldview of gender interactions, even doctor-patients conversations might become colored by it. The clips in this section show variations of patterns of conversation in the practice of conventional medicine.Asian StudiesHindi Urdu FlagshipSouth Asia Institut

Faith in Unani - Part 3

Unani (also spelt Yunani) refers to the tradition of Graeco-Arabic medicine. Like Ayurveda, this also a comprehensive tradition of medicine that goes back of Hippocrates, but owes a lot to the wisdom and experience of Arabic and Persian physicians. India remains one of the most prominent countries encouraging research and education in the field of Unani medicine. Listening to the Unani video clips will make the students aware of not only the concepts used in Unani medicine, but also the integral role of faith in healing.Asian StudiesHindi Urdu FlagshipSouth Asia Institut

Black Dhatura Preparation

Description of the Ayurvedic preparation process for Black Dhatura. Herbs like Amla, Black Dhatura, Karanj, Unga etc. are basic herbs used in Ayurveda for treating numerous ailments. There is a well prescribed process of preparing herbs for medicinal purposes. This process may include cutting, chopping, peeling, drying, leaching and mixing with other herbs before they can be used for treatment. The Ayurvedic doctor has to be very familiar with these processes to prepare the right kind of herbal medicine. Various parts of the same plant may require collection and preparation at different periods of time. The knowledge of this process of medicine preparation can be passed on from father to son, or taught in a formal course of study. Here are vignettes of how some of these are prepared for medicinal use.Asian StudiesHindi Urdu FlagshipSouth Asia Institut

Reasons for Preferring Ayurveda

South Asia in general, and India specifically, are regions with immense diversity in culture and language. Because of this conversations about medicine between doctors and patients takes different forms from one region to another. This is especially true when we look at urban, suburban and rural doctor-patient interactions. Added to these is the element of gender. Owing to the somewhat conservative worldview of gender interactions, even doctor-patients conversations might become colored by it. The clips in this section show variations of patterns of conversation in the practice of conventional medicine.Asian StudiesHindi Urdu FlagshipSouth Asia Institut

Unani Treatment - Part 2

Unani (also spelt Yunani) refers to the tradition of Graeco-Arabic medicine. Like Ayurveda, this also a comprehensive tradition of medicine that goes back of Hippocrates, but owes a lot to the wisdom and experience of Arabic and Persian physicians. India remains one of the most prominent countries encouraging research and education in the field of Unani medicine. Listening to the Unani video clips will make the students aware of not only the concepts used in Unani medicine, but also the integral role of faith in healing.Asian StudiesHindi Urdu FlagshipSouth Asia Institut