Download or read book Application of Laser Induced Fluorescence for Flow Diagnostics in Arc Jets written by Sivaram Arepalli and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Demonstration of the Feasibility of Laser Induced Fluorescence for Arc Jet Flow Diagnostics written by Sivaram Arepalli and published by . This book was released on 1989 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Flow Diagnostics of an Arcjet Using Laser induced Fluorescence written by John G. Liebeskind 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 Tracer based Planar Laser induced Fluorescence Diagnostics written by Brian Ho-yin Cheung and published by Stanford University. This book was released on 2011 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two advances to tracer-based planar laser-induced fluorescence (PLIF) diagnostics are presented in this work. The first improvement is the development of a 3-pentanone fluorescence quantum yield (FQY) database and model for a wide range of conditions in support of quantitative PLIF diagnostics. In addition, this work presents a sensitive, time-resolved tracer-based PLIF diagnostic, accomplished by using a continuous-wave (CW) laser with the high-FQY tracer toluene. Because of its ease of use and desirable photophysical properties, PLIF diagnostics using 3-pentanone as a tracer are common, particularly for internal combustion engine (ICE) diagnostics. Thus, there is a need for 3-pentanone FQY measurements and modeling over a wide range of temperatures, pressures, and excitation wavelengths. For insight into the collisionless process in the FQY model, measurements were made in 3-pentanone vapor at low-pressures across a range of temperatures using a flowing cell. Laser excitation with 248, 266, 277, 308 nm wavelengths were utilized, and Rayleigh scattering of the laser beam was used to calibrate the optical efficiency of the collection optics and detector. This low-pressure data allows calculation of the 3-pentanone fluorescence rate and non-radiative de-excitation rate in the fluorescence model. The vibrational relaxation cascade parameter for 3-pentanone collisions was also determined. Measurements of 3-pentanone FQY were also made over a range of temperatures and pressures relevant to diagnostic applications, and, in particular, combined high-temperature and high-pressure conditions applicable to internal combustion engines (ICE). These data were collected in a custom-built optical cell capable of simultaneous high-pressure and high-temperature conditions. The behavior of the FQY in nitrogen for temperatures up to 745 K and in air up to 570 K was examined for pressures from 1 to 25 bar. These data were used to further optimize the parameters in the FQY model representing collisional processes. The large quantity of data with 308 nm excitation allowed optimization of the nitrogen quenching rate, and data in air were used to optimize the oxygen quenching rate. These data were also used to optimize the vibrational relaxation parameters for nitrogen and oxygen. The model with the updated parameters is consistent with the data collected in the current work, as well as with fluorescence measurements made in optical ICEs up to 1100 K and 28 bar. Another area of tracer-based PLIF diagnostics development is time-resolved imaging. Because PLIF diagnostics are often performed using pulsed lasers, the time resolution of measurements is limited to the pulse rate of laser. Use of a high-powered visible laser with an off-the-shelf cavity frequency doubler is shown to produce a moderate-power CW beam in the ultraviolet wavelength regime. Application of this CW source to excite toluene, a high-FQY tracer, yields a sensitive, time-resolved tracer-based PLIF diagnostic. Fluctuation detection limits for tracer mole fraction were investigated by applying the diagnostic to an atmospheric temperature and pressure nitrogen jet seeded with 4% toluene, and detection limits of better than 1% of the maximum toluene mole fraction were achieved for detection of fluorescence signal at a point, along a line, and over a plane. The diagnostic was also demonstrated on a turbulent jet for line and planar detection and demonstrated the potential for toluene time-resolved PLIF diagnostics with CW lasers.

Download or read book Characterization of Arc jet Flows Using Laser induced Fluorescence written by Douglas J. Bamford and published by . This book was released on 1994 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 Applications of Planar Laser induced Fluorescence Imaging Diagnostics to Reacting Flows written by P. H. Paul and published by . This book was released on 1990 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical Diagnostics in Fluid and Thermal Flow written by Soyoung S. Cha and published by SPIE-International Society for Optical Engineering. This book was released on 1993 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Application of Laser Induced Fluorescence as a Plasma Diagnostic Technique written by Susan Hilary Law and published by . This book was released on 1986 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Emission and Laser induced Fluorescence Diagnostics of a Supersonic Jet of Plasma heated Nitrogen written by Lawrence Mark Cohen and published by . This book was released on 1990 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiplexed Laser Induced Fluorescence and Non Equilibrium Processes in Arcjets written by and published by . This book was released on 1994 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the past five years there has been an ongoing experimental and analytical program at the University of Tennessee Space Institute (UTSI) to improve our understanding of arcjet physics. A computational model that assumed local thermodynamic equilibrium was first used to simulate arcjet thrusters operating on ammonia, hydrogen, and argon. The UTSI arcjet code was later extended to include a two temperature, finite rate kinetic model for hydrogen plasma. Recently, this code has been used to simulate a radiation-cooled arcjet (MARC thruster) experiment and a water-cooled arcjet (TT1 thruster) experiment performed at The Universitat Stuttgart Institut fur Raumfahrtsysteme. The results of these simulations are presented along with a review of UTSI arcjet computation code development. A two-beam multiplexed laser induced fluorescence (LIF) technique was developed at UTSI to provide detailed measurements of arcjet flows near the nozzle exit plane. Comparison of detailed flowfield measurements with predictions of the computation model were used to provide insight into the physical models used in the arcjet code. The method was first demonstrated using a small, 300 W, water-cooled arcjet operated with argon propellant. The method was then applied to a 1 kW arcjet operated with hydrogen and nitrogen propellant mixtures using the Balmer alpha line of hydrogen. Recently, the method has been extended to use an excited state line in nitrogen. The results of this most recent research are presented. (MM).

Download or read book Applications of Laser induced Fluorescence to Medical Diagnostic Problems written by S. J. Davis and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Hypersonics written by Bertin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: These three volumes entitled Advances in Hypersonics contain the Proceedings of the Second and Third Joint US/Europe Short Course in Hypersonics which took place in Colorado Springs and Aachen. The Second Course was organized at the US Air Force Academy, USA in January 1989 and the Third Course at Aachen, Germany in October 1990. The main idea of these Courses was to present to chemists, com puter scientists, engineers, experimentalists, mathematicians, and physicists state of the art lectures in scientific and technical dis ciplines including mathematical modeling, computational methods, and experimental measurements necessary to define the aerothermo dynamic environments for space vehicles such as the US Orbiter or the European Hermes flying at hypersonic speeds. The subjects can be grouped into the following areas: Phys ical environments, configuration requirements, propulsion systems (including airbreathing systems), experimental methods for external and internal flow, theoretical and numerical methods. Since hyper sonic flight requires highly integrated systems, the Short Courses not only aimed to give in-depth analysis of hypersonic research and technology but also tried to broaden the view of attendees to give them the ability to understand the complex problem of hypersonic flight. Most of the participants in the Short Courses prepared a docu ment based on their presentation for reproduction in the three vol umes. Some authors spent considerable time and energy going well beyond their oral presentation to provide a quality assessment of the state of the art in their area of expertise as of 1989 and 1991.

Download or read book Application of Laser Induced Fluorescence LIF to Liquid Propellant Rocket Engine Testing written by C. Brasier and published by . This book was released on 1997 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion exhausts present a challenging problem for researchers due to the extremely harsh environment, and nonintrusive diagnostics are often sought to provide flow property information. Laser induced fluorescence (LIF) is one technique in which a chosen flow molecule or marker is probed to yield gross flow properties, such as static temperature and flow velocities. The work presented herein describes the application of LIF to the combustion exhausts of several full-scale liquid-propellant rocket engines spanning a wide range of operational parameters. The method is based upon the use of CW ring-dye lasers which scan in frequency over either the Na D1 or D2 line at 5896 and 5890 A. Na is used as a basis for this approach since it occurs as a trace element in both hydrogen and amine rocket fuels. The generic apparatus is described, including a discussion of the collection and interpretation of the LIF signal to yield radial and temporal profiles of radial flow velocity, static temperature, and fuel distribution. It was found that the LIF technique provides quality data in most cases. Certain stressing situations were also found in which data on the flow properties were not obtainable. Also, computational fluid dynamics (CFD) modeling of the plumes was used to provide baseline estimates of the exhaust flow properties. The model reasonably predicted the gross behavior of the flow as determined by the LIF technique, although some items of fine spatial structure were not reproduced very well.

Download or read book Emission and laser induced fluorescence diagnostics of a supersonic jet of plasma heated nitrogen written by Lawrence M. Cohen and published by . This book was released on 1992 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: