Download or read book Investigation of Interfacial Gas liquid Flows Using the Brightness Based Laser Induced Fluorescence Technique written by João Vasques and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strategies for Planar Laser induced Fluorescence Thermometry in Shock Tube Flows written by Ji Hyung Yoo and published by Stanford University. This book was released on 2011 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis was motivated by the need to better understand the temperature distribution in shock tube flows, especially in the near-wall flow regions. Two main ideas in planar laser-induced fluorescence (PLIF) diagnostics are explored in this thesis. The first topic is the development of a single-shot PLIF diagnostic technique for quantitative temperature distribution measurement in shock tube flow fields. PLIF is a non-intrusive, laser-based diagnostic technique capable of instantaneously imaging key flow features, such as temperature, pressure, density, and species concentration, by measuring fluorescence signal intensity from laser-excited tracer species. This study performed a comprehensive comparison of florescence tracers and excitation wavelengths to determine the optimal combination for PLIF imaging in shock tube flow applications. Excitation of toluene at 248nm wavelength was determined to be the optimal strategy due to the resulting high temperature sensitivity and fluorescence signal level, compared to other ketone and aromatic tracers at other excitation wavelengths. Sub-atmospheric toluene fluorescence yield data was measured to augment the existing photophysical data necessary for this diagnostic technique. In addition, a new imaging test section was built to allow PLIF imaging in all regions of the shock tube test section, including immediately adjacent to the side and end walls. The signal-to-noise (SNR) and spatial resolution of the PLIF images were optimized using statistical analysis. Temperature field measurements were made with the PLIF diagnostic technique across normal incident and reflected shocks in the shock tube core flow. The resulting images show uniform spatial distribution, and good agreement with conditions calculated from the normal shock jump equations. Temperature measurement uncertainty is about 3.6% at 800K. The diagnostic was also applied to image flow over a wedge. The resulting images capture all the flow features predicted by numerical simulations. The second topic is the development of a quantitative near-wall diagnostic using tracer-based PLIF imaging. Side wall thermal boundary layers and end wall thermal layers are imaged to study the temperature distribution present under constant pressure conditions. The diagnostic technique validated in the shock tube core flow region was further optimized to improve near-wall image quality. The optimization process considered various wall materials, laser sheet orientations, camera collection angles, and optical components to find the configuration that provides the best images. The resulting images have increased resolution (15[Mu]m) and are able to resolve very thin non-uniform near-wall temperature layers (down to 60[Mu]m from the surface). The temperature field and thickness measurements of near-wall shock tube flows under various shock conditions and test gases showed good agreement with boundary layer theory. To conclude this thesis, new applications and future improvements to the developed PLIF diagnostic technique are discussed. These suggested refinements can provide an even more robust and versatile PLIF imaging technique capable of measuring a wider range of flow conditions near walls.

Download or read book Annular Two Phase Flow written by Geoffrey Hewitt and published by Elsevier. This book was released on 2013-10-22 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annular Two-Phase Flow presents the wide range of industrial applications of annular two-phase flow regimes. This book discusses the fluid dynamics and heat transfer aspects of the flow pattern. Organized into 12 chapters, this book begins with an overview of the classification of the various types of interface distribution observed in practice. This text then examines the various regimes of two-phase flow with emphasis on the regions of occurrence of the annular flow regime. Other chapters consider the single momentum and energy balances, which illustrate the differences and analogies between single- and two-phase flows. This book discusses as well the simple modes for annular flow with consideration to the calculation of the profile of shear stress in the liquid film. The final chapter deals with the techniques that are developed for the measurement of flow pattern, entrainment, and film thickness. This book is a valuable resource for chemical engineers.

Download or read book Strategies for Planar Laser induced Fluorescence Thermometry in Shock Tube Flows written by Ji Hyung Yoo and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis was motivated by the need to better understand the temperature distribution in shock tube flows, especially in the near-wall flow regions. Two main ideas in planar laser-induced fluorescence (PLIF) diagnostics are explored in this thesis. The first topic is the development of a single-shot PLIF diagnostic technique for quantitative temperature distribution measurement in shock tube flow fields. PLIF is a non-intrusive, laser-based diagnostic technique capable of instantaneously imaging key flow features, such as temperature, pressure, density, and species concentration, by measuring fluorescence signal intensity from laser-excited tracer species. This study performed a comprehensive comparison of florescence tracers and excitation wavelengths to determine the optimal combination for PLIF imaging in shock tube flow applications. Excitation of toluene at 248nm wavelength was determined to be the optimal strategy due to the resulting high temperature sensitivity and fluorescence signal level, compared to other ketone and aromatic tracers at other excitation wavelengths. Sub-atmospheric toluene fluorescence yield data was measured to augment the existing photophysical data necessary for this diagnostic technique. In addition, a new imaging test section was built to allow PLIF imaging in all regions of the shock tube test section, including immediately adjacent to the side and end walls. The signal-to-noise (SNR) and spatial resolution of the PLIF images were optimized using statistical analysis. Temperature field measurements were made with the PLIF diagnostic technique across normal incident and reflected shocks in the shock tube core flow. The resulting images show uniform spatial distribution, and good agreement with conditions calculated from the normal shock jump equations. Temperature measurement uncertainty is about 3.6% at 800K. The diagnostic was also applied to image flow over a wedge. The resulting images capture all the flow features predicted by numerical simulations. The second topic is the development of a quantitative near-wall diagnostic using tracer-based PLIF imaging. Side wall thermal boundary layers and end wall thermal layers are imaged to study the temperature distribution present under constant pressure conditions. The diagnostic technique validated in the shock tube core flow region was further optimized to improve near-wall image quality. The optimization process considered various wall materials, laser sheet orientations, camera collection angles, and optical components to find the configuration that provides the best images. The resulting images have increased resolution (15[Mu]m) and are able to resolve very thin non-uniform near-wall temperature layers (down to 60[Mu]m from the surface). The temperature field and thickness measurements of near-wall shock tube flows under various shock conditions and test gases showed good agreement with boundary layer theory. To conclude this thesis, new applications and future improvements to the developed PLIF diagnostic technique are discussed. These suggested refinements can provide an even more robust and versatile PLIF imaging technique capable of measuring a wider range of flow conditions near walls.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1994 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser induced Fluorescence particle Tracking System for Stratified Flow Research written by H. J. S. Fernando and published by . This book was released on 1993* with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Induced Fluorescence Gas Puff Density Measurements written by Matthew Thomas Evans and published by . This book was released on 2012 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The double gas puff valve is a device used to inject a supersonic puff of gas to act as a load in z-pinch plasma implosions. The purpose of the annular gas shells is to mimic a cylindrical column along the z-axis in efforts to reduce Rayleigh-Taylor instability. However before integration of the valve into the zpinch pulsed power machine the gas profile needs to be examined. Tuning the density of the gas to fit specific profiles leads to improvement in plasma radiative sources and yields. The axial uniformity of the cylindrical gas column is highly dependent on the nozzle characteristics and shape. Performance is then determined by the density, speed, and symmetry of the gas column. Measurement of the density distribution is performed using a spectroscopic measuring technique called laser-induced fluorescence. LIF is a 1-dimensional imaging technique that maps the concentration of atoms with the aid of a tracer. LIF and the 2-dimensional counterpart planar laser-induced fluorescence (PLIF) examine the gas flow in the r-z plane with sub-millimeter resolution. The tracer molecule fluoresces due to excitation by a laser beam. The fluorescence signal is imaged using a streak camera and a charge-coupled-device (CCD) in combination. The method also allows the study of gas puff reliability. Any differences between gas shells can then be examined and interpreted with reliable certainty. Imaging software is used to determine the density from the intensity of the fluorescence images. A detail account of the process is illustrated in this study. A control system was constructed for operations of the gas puff valve in both LIF and z-pinch experiments. The pressure system is designed to tailor specific profiles as needed. The LIF system is detailed along with any components built for the gas puff valve. Results of these measurements serve to verify the uniformity of flow and determine the density distribution of the gas puff.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Fiber Optics and Laser induced Fluorescence for Remote Measurements of UF6 in Strong Rotation written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced fluorescence (LIF) and other laser-based techniques are being employed in an increasing number of gas and flow field diagnostic applications. In some instances, the necessary instrumentation requires unavailable space and is not portable. Sometimes the process region of interest is relatively inaccessible. These factors complicate and hinder deployment of laser diagnostic techniques. A fiber optics based method for delivering the laser and for returning optical signals can be used to circumvent these problems. Reported here is a demonstration of a fiber optics system for remote monitoring of UF6 density and temperature by the LIF method. The description consists of a discussion of a fiber system that conveys the laser beam to the points of interest and a fiber system which transmits the LIF signal to a photomultiplier tube. Representative results from a static gas cell and a centrifuge are presented.

Download or read book NO2 based Laser induced Fluorescence LIF Technique to Measure Cold flow Mixing written by A. Gulati and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Fiber Optics and Laser induced Fluorescence for Remote Measurements of UF6 in Strong Rotation written by Stephen William Allison and published by . This book was released on 1983 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced fluorescence (LIF) and other laser-based techniques are being employed in an increasing number of gas and flow field diagnostic applications. In some instances, the necessary instrumentation requires unavailable space and is not portable. Sometimes the process region of interest is relatively inaccessible. These factors complicate and hinder deployment of laser diagnostic techniques. A fiber optics based method for delivering the laser and for returning optical signals can be used to circumvent these problems. Reported here is a demonstration of a fiber optics system for remote monitoring of UF6 density and temperature by the LIF method. The description consists of a discussion of a fiber system that conveys the laser beam to the points of interest and a fiber system which transmits the LIF signal to a photomultiplier tube. Representative results from a static gas cell and a centrifuge are presented.

Download or read book Laser Induced Fluorescence Modulation Techniques for Velocity Measurements in Gas Flows written by C. Hassa and published by . This book was released on 1987 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Broadband fluorescence of iodine, excited at 514.5 nm by a single-mode argon-ion laser tuned to the quasi-linear part of an absorption line, was used to detect the Doppler shift and hence the velocity of iodine molecules seeded in a nitrogen jet flow. The slope of the absorption line profile was measured directly using a frequency shift introduced by acoustooptic modulators (AOMs). A velocity of 36 m/s was measured in a jet of N2 at 60 Torr in 2 ms with an accuracy of 11%. To reduce experimental noise, the laser beams were switched at 125 KHz and signal-tuned amplification was used. Keywords: velocity, Iodine, Laser, Fluorescence.

Download or read book Advances in Chemical Engineering written by and published by Academic Press. This book was released on 2009-09-01 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-scale analysis and simulation of chemical processing and reactions have received unprecedented attention in recent years; however, measurement technology focused on multi-scale structures, particularly on meso-scale phenomena, has not been sufficiently addressed. This volume of Advances in Chemical Engineering focuses on the "Characterization of Flow, Particles and Interfaces" to alert the chemical engineering community to this challenging issue presenting six meso-scale measurement technologies.

Download or read book Laser Ablation in Liquids written by Guowei Yang and published by CRC Press. This book was released on 2012-02-22 with total page 1166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the fundamental concepts and physical and chemical aspects of pulsed laser ablation of solid targets in liquid environments and its applications in the preparation of nanomaterials and fabrication of nanostructures. The areas of focus include basic thermodynamic and kinetic processes of laser ablation in liquids, and its applic

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Encyclopedia Of Thermal Packaging Set 1 Thermal Packaging Techniques A 6 volume Set written by and published by World Scientific. This book was released on 2012-09-25 with total page 1582 pages. Available in PDF, EPUB and Kindle. Book excerpt: remove This Encyclopedia comes in 3 sets. To check out Set 2 and Set 3, please visit Set 2: Thermal Packaging Tools and Set 3: Thermal Packaging Applications /remove Thermal and mechanical packaging — the enabling technologies for the physical implementation of electronic systems - are responsible for much of the progress in miniaturization, reliability, and functional density achieved by electronic, microelectronic, and nanoelectronic products during the past 50 years. The inherent inefficiency of electronic devices and their sensitivity to heat have placed thermal packaging on the critical path of nearly every product development effort in traditional, as well as emerging, electronic product categories.Successful thermal packaging is the key differentiator in electronic products, as diverse as supercomputers and cell phones, and continues to be of pivotal importance in the refinement of traditional products and in the development of products for new applications. The Encyclopedia of Thermal Packaging, compiled in multi-volume sets (Set 1: Thermal Packaging Techniques, Set 2: Thermal Packaging Tools, Set 3: Thermal Packaging Applications, and Set 4: Thermal Packaging Configurations) will provide a comprehensive, one-stop treatment of the techniques, tools, applications, and configurations of electronic thermal packaging. Each of the author-written sets presents the accumulated wisdom and shared perspectives of a few luminaries in the thermal management of electronics.Set 1: Thermal Packaging TechniquesThe first set of the Encyclopedia, Thermal Packaging Techniques, focuses on the technology “building blocks” used to assemble a complete thermal management system and provide detailed descriptions of the underlying phenomena, modeling equations, and correlations, as well as guidance for achieving the optimal designs of individual “building blocks” and their insertion in the overall thermal solution. Specific volumes deal with microchannel coolers, cold plates, immersion cooling modules, thermoelectric microcoolers, and cooling devices for solid state lighting systems, as well as techniques and procedures for the experimental characterization of thermal management components. These “building blocks” are the essential elements in the creation of a complete, cost-effective thermal management system.The four sets in the Encyclopedia of Thermal Packaging will provide the novice and student with a complete reference for a quick ascent on the thermal packaging ';learning curve,'; the practitioner with a validated set of techniques and tools to face every challenge, and researchers with a clear definition of the state-of-the-art and emerging needs to guide their future efforts. This encyclopedia will, thus, be of great interest to packaging engineers, electronic product development engineers, and product managers, as well as to researchers in thermal management of electronic and photonic components and systems, and most beneficial to undergraduate and graduate students studying mechanical, electrical, and electronic engineering.

Download or read book Encyclopedia of Thermal Packaging Set 1 Thermal Packaging Techniques a 6 Volume Set written by Avram Bar-Cohen and published by World Scientific. This book was released on 2012-02-01 with total page 1582 pages. Available in PDF, EPUB and Kindle. Book excerpt: Packaging, the physical design and implementation of electronic systems is responsible for much of the progress in miniaturization, reliability and functional density achieved by the full range of electronic, microelectronic and nanoelectronic products during the past several decades. The inherent inefficiency of electronic devices and their sensitivity to heat have placed thermal management on the critical path of nearly every organization dealing with traditional electronic product development, as well as emerging, product categories. Successful thermal packaging is the key differentiator in electronic products, as diverse as supercomputers and cell phones, and continues to be of critical importance in the refinement of traditional products and in the development of products for new applications.The Encyclopedia of Thermal Packaging, compiled into four 5-volume sets (Thermal Packaging Techniques, Thermal Packaging Configurations, Thermal Packaging Tools and Thermal Packaging Applications), will provide comprehensive, one-stop treatment of the techniques, configurations, tools and applications of electronic thermal packaging. Each volume in a set comprises 250–350 pages and is written by world experts in thermal management of electronics.