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 Micro and Macro Mixing written by Henning Bockhorn and published by Springer Science & Business Media. This book was released on 2009-12-26 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: The homogenization of single phase gases or liquids with chemical reactive components by mixing belongs to one of the oldest basic operations applied in chemical engineering. The mixing process is used as an essential step in nearly all processes of the chemical industry as well as the pharmaceutical and food ind- tries. Recent experimentally and theoretically based results from research work lead to a fairly good prediction of the velocity fields in differend kinds of mixers, where as predictions of simultaneously proceeding homogeneous chemical re- tions, are still not reliable in a similar way. Therefore the design of equipment for mixing processes is still derived from measurements of the so called “mixing time” which is related to the applied methods of measurement and the special - sign of the test equipment itself. The cooperation of 17 research groups was stimulated by improved modern methods for experimental research and visualization, for simulations and nume- cal calculations of mixing and chemical reactions in micro and macro scale of time and local coordinates. The research work was financed for a six years period within the recently finished Priority Program of the German Research Foundation (DFG) named “Analysis, modeling and numerical prediction of flow-mixig with and without chemical reactions (SPP 1141)”. The objective of the investigations was to improve the prediction of efficiencies and selectivities of chemical re- tions on macroscopic scale.
Download or read book 30th Aerospace Sciences Meeting and Exhibit 92 0490 92 0528 written by and published by . This book was released on 1992 with total page 520 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 International Aerospace Abstracts written by and published by . This book was released on 1992 with total page 1666 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Direct Low Pressure Laser induced Fluorescence Measurement Technique for NO2 Ambient Measurements and Urban NOx Chemistry written by Linda Acha George and published by . This book was released on 1991 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Micromechanical Systems written by and published by . This book was released on 1992 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Commissioning a Commercial Laser Induced Fluorescence System for Characterization of Static Mixer Performance written by Madhumitha Ezhilan and published by . This book was released on 2017 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent mixing with a static mixer is studied using the Laser Induced Fluorescence (LIF) technique. In this study, a comparison of the blending effectiveness with and without the static mixer is drawn. The blending efficiency of the mixer is quantified by coefficient of variation (CoV), where a value of 0.05 signifies very good mixing. The lower the value of CoV, the better the blending quality. Two types of CoV, instantaneous and time-averaged, are determined to study the blending quality. For industrial purposes, the time-averaged CoV is typically used to characterize the mixing system. Data is collected at different Reynolds numbers and different distances from the point of injection of the dye. A commercial laser imaging software, DaVis, is used for the analysis of the data. The study shows that the software uses a different approach than what is expected to calculate the average instantaneous CoV which is incorrect and lower than the time-averaged CoV. A macro developed by Casselbury (2016) is adopted to calculate the average instantaneous CoV. Results show that mixing quality increased with increase in flow rate or mixing length. Also, the CoV values for tests with the static mixer are found to be lower than the empty pipeline which indicated that better mixing is achieved when the static mixer is used.
Download or read book 92 3335 92 3364 written by and published by . This book was released on 1992 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ASME Technical Papers written by and published by . This book was released on 1997 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Low pressure Laser Induced Fluorescence for Measuring Temperature Profiles in a Rarefied Gas written by Thomas Orville Leimkuehler and published by . This book was released on 2000 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a rarefied gas, heat transfer in the transition regime (i.e., Knudsen number range of 0.1 to 10) is affected by molecular as well as gas-surface interactions. Theoretical results for the heat transfer can be obtained through computational solutions of the Boltzmann equation and appropriate intermolecular and gas-surface interaction models. As with all computational and phenomenological models, experimental verification is required. In this work, a low-pressure laser induced fluorescence (LIF) technique is investigated for measuring temperature profiles between parallel flat plates, and the results are compared to theoretical predictions. Iodine vapor is used as the gas medium due to its attractive spectral properties. Two surfaces of a closed, short cylindrical iodine cell are employed as a parallel flat plate geometry and are maintained at different temperatures. Cold and hot plate temperature combinations of (1) 20°C and 70°C, respectively, and (2) 20°C and 115°C, respectively, were used. Calibration measurements were performed at uniform temperatures of 45°C and 70°C, Solid iodine stem temperatures of 0°C and -20°C, corresponding to pressures of 30 mtorr and 3 mtorr, respectively, and Knudsen numbers of 0.05 and 0.5, respectively, were investigated. The data shows the expected trends, indicating observable temperature jumps at the surfaces and matching well with the theoretical predictions in the bulk gas. Deviations from the theory were largest near the surface, possibly a result of the limitations of the theoretical models for this particular experimental case. In addition, problems stemming from fluctuations of the chamber pressure as well as attenuation of the excitation laser beam affected collection of definitive temperature profile measurements. However, much progress with the low-pressure LIF technique has been made, and the technique continues to look promising for obtaining accurate and reliable temperature profile measurements in the transition regime.
Download or read book Paper written by and published by . This book was released on 1997 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Springer Handbook of Experimental Fluid Mechanics written by Cameron Tropea and published by Springer Science & Business Media. This book was released on 2007-10-09 with total page 1570 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accompanying DVD-ROM contains ... "all chapters of the Springer Handbook."--Page 3 of cover.
Download or read book Demonstration of the Feasibility of Laser Induced Fluorescence for Arc Jet Flow Diagnostics written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser Induced Fluorescence (LIF) studies are carried out on nitric oxide and oxygen molecules in the arc jet flows at the NASA Johnson Space Center Reentry Testing Facility. Measurements are taken in the free stream and from a blunt body shock layer. Tests are performed under different flow conditions to determine the feasibility and sensitivity of the LIF technique for various species. This is developed as a part of high enthalpy flow diagnostics and will be useful to elucidate the rotational and vibrational temperatures. Adequate sensitivity for the detection of O(2) and NO is demonstrated. Proposed improvements of the existing system are presented. Arepalli, Sivaram Unspecified Center NAS9-17900...
Download or read book Kinetics and Magnetic Field Effects on Laser Induced Fluorescence in NO2 written by Gary Raymond Gust and published by . This book was released on 1978 with total page 452 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 . 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 O2 I Laser Oxygen Iodine Mixing Studies Using LIF Laser Induced Fluorescence written by Y. D. Jones and published by . This book was released on 1987 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser - Induced Fluorescence (LIF) was incorporated to study the degree of mixing in two subsonic nozzle variations for the O-I laser system. The studies were performed using a testbed version of COIL-IV, an O-I laser. I was injected through the nozzles and excited with an Ar laser to produce fluorescence. The observed jet trajectories could then be compared to trajectories predicted by computer models. Velocity distributions were measured at several flow rates. The LIF allowed for an evaluation of the relative degree of mixing produced by the two nozzles resulting in a modification of the O-I laser. Keywords: Oxygen iodine, Laser induced fluorescence, Nozzle, Fluid dynamics, Subsonic mixing.
