Download or read book Development and Application of Advanced Optical Diagnostics for the Study of High Speed Flows in Micro Systems written by and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary goal of this research program is the development and application of laser based flow diagnostics for the study of supersonic micro-nozzles, such as those, which might be employed for flow control and/or small satellite orbit maintenance. In this report we document the significant progress that has been made in FY-02 in the development of Molecular Tagging Velocimetry (MTV), including assessment of experimental accuracy at low (0.10 - 3 torr) static pressure and detailed comparisons between experimental flow field data and computational predictions using the Direct Simulation Monte Carlo (DSMC) method. Progress in the development of micro Planar Doppler Velocimetry (micro PDV) is also described.

Download or read book A Study of High Speed Flows Using Advanced Optical Diagnostics written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few years, we have been working on the development of advanced optical diagnostics to be used in high speed flows. Our focus has been on the techniques based on molecular absorption filters. The focus of this report is on the details of a two-component planar measurement that we call Planar Doppler Velocimetry (PDV) technique. A PDV technique was developed and used to measure two components of instantaneous velocity in an ideally expanded, Mach 2, free jet. The technique utilizes a molecular filter as a frequency discriminator and uses two cameras to resolve two components of velocity on a plane that is illuminated by a laser sheet. Careful formation of the laser sheet, proper calibration of the splitter/recombiner imaging system and precise image registration were found to be critical steps in the technique. The velocity measurements obtained with this technique were compared with reference LDV measurements taken in the same flowfield. The mean velocity results were in very good agreement with the reference measurements and the turbulence results captured only the correct trend. A detailed error analysis describes the error sources inherent in the PDV technique. For the current two-component PDV system the estimated uncertainty for the mean velocity was better than +/-5%. Methods to improve the technique are discussed.

Download or read book Advanced Optical Diagnostics in High Speed Flows written by M. Samimy and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical Diagnostics for Flow Processes written by P. Buchhave and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin of optical methods for fluid flow investigations appears to be nontraceable. This is no matter for surprise. After all seeing provides the most direct and common way for humans to learn about their environment. But at the same time some of the most sophisticated methods for doing measurements in fluids are also based on light and often laser light. A very large amount of material has been published in this area over the last two decades. Why then another publication? Well, the field is still in a state of rapid development. It is characterised by the use of results and methods developed within very different areas like optical physics, spectroscopy, communication systems, electronics and computer science, mechanical engineering, chemical engineering and, of course, fluid dynamics. We are not aware of a book containing both introductory and more advanced material that covers the same material as presented here. The book is the result of a compilation and expansion of material presented at a summer school on Optical Diagnosticsfor Flow Processes,held at RiS0 National Laboratory and the Technical University of Denmark in September 1993. The aim of the course was to provide a solid background for understanding, evaluating, and using modem optical diagnostic methods, addressing Ph. D. students and researchers active in areas of fluid flow research. The disciplines represented by the participants ranged from atmospheric fluid dynamics to biomedicine.

Download or read book Advanced Optical and 3D Reconstruction Diagnostics for Combustion and Fluids Research written by Qian Wang and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Imaging based optical diagnostics have played an important role in combustion and fluids studies. However, most imaging techniques are two dimensional. The increasing interest in accurate whole field measurement has heightened the need for developing three dimensional methods. Furthermore, many flows are inherently 3D in nature. One aim of this study is to develop an innovative 3D schlieren/shadowgraph system based on conventional schlieren/shadowgraph techniques. Furthermore, several research issues related to fluid mechanics and combustion are investigated using multi optical methods, including high speed direct/schlieren imaging, stereo imaging and 3D reconstruction and PIV techniques, etc. Firstly, a stereoscopic shadowgraph system has been developed using two sets of conventional z-type schlieren configurations. The test volume is set at the intersection of two inclined converging beams formed by two pairs of parabolic mirrors. Two synchronised high speed cameras are used to record the shadowgraph image pairs simultaneously. A precisely etched metal mesh plate is used to calibrate the stereoscopic shadowgraph system. The fully developed MATLAB code is employed to obtain calibration parameters and 3D coordinates reconstruction. A crystal block with internal 3D images is acted as a static model for point reconstruction. The 3D coordinates obtained are in good agreement with the real dimensions. The technique has been subsequently applied to investigate the bursting dynamics of a bubble. The 3D curve reconstruction is also accomplished successfully. The stereoscopic shadowgraph technique has been shown to be an effective method for both 3D visualisation and quantitative measurement. Secondly, the spark induced hot gas jet of a gas turbine combustor igniter has been investigated using optical methods with the combination of high speed schlieren and stereo imaging. A spherical shockwave and a hot gas jet are observed after spark initiation. The 3D velocity vectors of the flying off metal bits are calculated by a stereo imaging and reconstruction algorithm. It has been found that the amount and velocity distributions of the eroded metal bits are very different even at a fixed input voltage to the igniter, which contrasts with the quite consistent hot gas jet development. The 3D structures of the interaction boundaries between hot gas and ambient air are reconstructed for the first time using stereoscopic shadowgraph technique. Thirdly, the vortex dynamics and structures of methane-air diffusion flames are investigated under different co-flow conditions. The schlieren and PIV images show that the visible flame flickering is dominated by the dynamics of the external toroidal vortices outside. The co-flow air is observed to push the initiation point of toroidal vortices beyond the visible flame height and suppress flame flickering completely. The velocity vectors and vorticity contours at different air flow rates are presented and analysed. The shedding frequency of the toroidal vortex is found to be consistent with the result obtained from a photomultiplier. The investigation indicates that co-flow helps to depress flame instability by changing the vortex evolution. Finally, a laminar diffusion flame is studied under external acoustic excitation at different frequencies (6 Hz-100 Hz). The flame structures and vortex evolutions are investigated using high-speed stereo/schlieren imaging and digital imaging processing techniques. The flame frequency shows obvious nonlinear response to both the excitation frequency and amplitude. Several typical nonlinear phenomena were observed and analysed, which may serve as proof for relevant numerical simulation.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Research and Technology Program Digest written by United States. National Aeronautics and Space Administration and published by . This book was released on with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research Awards Index written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research and Technology Program Digest Flash Index written by and published by . This book was released on 1967 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical Diagnostics for Thin Film Processing written by Irving P. Herman and published by Elsevier. This book was released on 1996-10-23 with total page 815 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume describes the increasing role of in situ optical diagnostics in thin film processing for applications ranging from fundamental science studies to process development to control during manufacturing. The key advantage of optical diagnostics in these applications is that they are usually noninvasive and nonintrusive. Optical probes of the surface, film, wafer, and gas above the wafer are described for many processes, including plasma etching, MBE, MOCVD, and rapid thermal processing. For each optical technique, the underlying principles are presented, modes of experimental implementation are described, and applications of the diagnostic in thin film processing are analyzed, with examples drawn from microelectronics and optoelectronics. Special attention is paid to real-time probing of the surface, to the noninvasive measurement of temperature, and to the use of optical probes for process control. Optical Diagnostics for Thin Film Processing is unique. No other volume explores the real-time application of optical techniques in all modes of thin film processing. The text can be used by students and those new to the topic as an introduction and review of the subject. It also serves as a comprehensive resource for engineers, technicians, researchers, and scientists already working in the field. The only volume that comprehensively explores in situ, real-time, optical probes for all types of thin film processing Useful as an introduction to the subject or as a resource handbook Covers a wide range of thin film processes including plasma etching, MBE, MOCVD, and rapid thermal processing Examples emphasize applications in microelectronics and optoelectronics Introductory chapter serves as a guide to all optical diagnostics and their applications Each chapter presents the underlying principles, experimental implementation, and applications for a specific optical diagnostic

Download or read book Aeronautical Engineering written by and published by . This book was released on 1991 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and Application of High Speed Optical Diagnostic Techniques for Conducting Scalar Measurements in Internal Combustion Engines written by James D. Smith and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Briefs written by and published by . This book was released on 1990 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1996 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modern Optical Methods in Gas Dynamic Research written by Darshan Dosanjh and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is based on material prepared by the contributors to the symposium on "Progress in Gas Dynamic Research by Optical Methods", held on May 25-26, 1970 in the Department of Mechanical and Aerospace Engineering at Syracuse University. The contents focus on experimental and analytical aspects of contemporary op tical methods as applied in modern research on high speed and/or high temperature gaseous flows. State of the art, recent research results and possible research applications of spectroscopy, spectral interferometry, pulse laser holographic interferometry, laser as a diagnostic and plasma generating tool and the analysis of plasma by light scattering constitute part of the subject matter of this vol ume. The emerging importance and impact of recent laser developments on optical diagnostics of gas dynamic and gas-physics phenomena is a recurring theme throughout the volume. Diverse applications of the shock tube to process gases to high temperature equilibrium conditions and the study of important char acteristics of these radiating gases by contemporary spectroscopic methods are discussed in papers by Nicholls, Wurster and Wares, et al. Refractivity index measurements have long been extensively used for investigating gas dynamic and aerodynamic flows. However, the recent availability of the laser as a light source has brought sig nificant improvements in the more conventional optical methods such as schlieren photography and interferometry as reported here in Alcock's paper. More recent laser developments have resulted in several com pletely new optical diagnostic methods.

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt: