The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform

Ronald K. Hanson - One of the best experts on this subject based on the ideXlab platform.

  • two color laser absorption near 5 μm for Temperature and nitric oxide sensing in High Temperature Gases
    Journal of Quantitative Spectroscopy & Radiative Transfer, 2017
    Co-Authors: Christopher A Almodovar, Mitchell R Spearrin, Ronald K. Hanson
    Abstract:

    Abstract An infrared laser-absorption technique for in situ Temperature and nitric oxide species sensing in High-Temperature Gases is presented. A pair of quantum cascade lasers in the mid-infrared near 5 μm were utilized to probe rovibrational transitions in nitric oxide's fundamental band. The line parameters of the selected transitions, including line strengths and collision broadening coefficients of nitric oxide with argon and nitrogen, were evaluated during controlled room-Temperature static cell experiments and High-Temperature shock tube experiments at Temperatures between 1000 and 3000 K, and pressures between 1 and 5 atm. These studies provided new insights into the Temperature dependence of nitric oxide collision broadening, Highlighting the inadequacies of the power law over a broad Temperature range. With an accurate spectroscopic model over a broad Temperature range, the quantitative two-color Temperature sensing strategy was demonstrated in non-reactive shock tube experiments from 1000 to 3000 K to validate thermometry and during a nitric oxide formation experiment near 1700 K and 4 atm to Highlight capability for temporally-resolved species measurements at MHz rates. The technique has applicability for sensing in a broad range of flow fields that involve High-Temperature air.

  • wavelength modulation spectroscopy near 1 4 µm for measurements of h2o and Temperature in High pressure and Temperature Gases
    Measurement Science and Technology, 2014
    Co-Authors: Christopher S Goldenstein, R. Mitchell Spearrin, Ian A Schultz, Jay B Jeffries, Ronald K. Hanson
    Abstract:

    The development, validation and demonstration of a two-color tunable diode laser (TDL) absorption sensor for measurements of Temperature and H2O in High-pressure and High-Temperature Gases are presented. This sensor uses first-harmonic-normalized wavelength-modulation spectroscopy with second-harmonic detection (WMS-2f/1f) to account for non-absorbing transmission losses and emission encountered in harsh, High-pressure environments. Two telecommunications-grade TDLs were used to probe H2O absorption transitions near 1391.7 and 1469.3 nm. The lasers were frequency-multiplexed and modulated at 160 and 200 kHz to enable a measurement bandwidth up to 30 kHz along a single line-of-sight. In addition, accurate measurements are enabled at extreme conditions via an experimentally derived spectroscopic database. This sensor was validated under low-absorbance (<0.05) conditions in shock-heated H2O–N2 mixtures at Temperatures and pressures from 700 to 2400 K and 2 to 25 atm. There, this sensor recovered the known Temperature and H2O mole fraction with a nominal accuracy of 2.8% and 4.7% RMS, respectively. Lastly, this sensor resolved expected transients with High bandwidth and High precision in a reactive shock tube experiment and a pulse detonation combustor.

  • multi band infrared co2 absorption sensor for sensitive Temperature and species measurements in High Temperature Gases
    Applied Physics B, 2014
    Co-Authors: R. Mitchell Spearrin, Jay B. B. Jeffries, Ronald K. Hanson
    Abstract:

    A continuous-wave laser absorption diagnostic, based on the infrared CO2 bands near 4.2 and 2.7 μm, was developed for sensitive Temperature and concentration measurements in High-Temperature gas systems using fixed-wavelength methods. Transitions in the respective R-branches of both the fundamental υ3 band (~2,350 cm−1) and combination υ1 + υ3 band (~3,610 cm−1) were chosen based on absorption line-strength, spectral isolation, and Temperature sensitivity. The R(76) line near 2,390.52 cm−1 was selected for sensitive CO2 concentration measurements, and a detection limit of <5 ppm was achieved in shock tube kinetics experiments (~1,300 K). A cross-band, two-line thermometry technique was also established utilizing the R(96) line near 2,395.14 cm−1, paired with the R(28) line near 3,633.08 cm−1. This combination yields High Temperature sensitivity (ΔE” = 3,305 cm-1) and expanded range compared with previous intra-band CO2 sensors. Thermometry performance was validated in a shock tube over a range of Temperatures (600–1,800 K) important for combustion. Measured Temperature accuracy was demonstrated to be better than 1 % over the entire range of conditions, with a standard error of ~0.5 % and µs temporal resolution.

  • Multi-band infrared CO2absorption sensor for sensitive Temperature and species measurements in High-Temperature Gases
    Applied Physics B: Lasers and Optics, 2014
    Co-Authors: R. Mitchell Spearrin, W Ren, Jay B. B. Jeffries, Ronald K. Hanson
    Abstract:

    A continuous-wave laser absorption diagnostic, based on the infrared CO2 bands near 4.2 and 2.7 μm, was developed for sensitive Temperature and concentration measurements in High-Temperature gas systems using fixed-wavelength methods. Transitions in the respective R-branches of both the fundamental υ 3 band (~2,350 cm−1) and combination υ 1 + υ 3 band (~3,610 cm−1) were chosen based on absorption line-strength, spectral isolation, and Temperature sensitivity. The R(76) line near 2,390.52 cm−1 was selected for sensitive CO2 concentration measurements, and a detection limit of

  • tdl absorption sensor for Temperature measurements in High pressure and High Temperature Gases
    50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
    Co-Authors: Christopher S Goldenstein, Jay B. B. Jeffries, Ian A Schultz, Ronald K. Hanson
    Abstract:

    The development and demonstration of a tunable diode laser (TDL) absorption sensor for Temperature measurements in High-pressure and High-Temperature Gases is presented. This sensor uses a wavelength modulation spectroscopy with second-harmonic detection (WMS-2f) technique with a sensor bandwidth of 10 kHz. Two-color thermometry was performed using water vapor absorption features near 1392 and 1469 nm. Sensor performance was validated with measurements in a heated static cell and shock-heated N2-H2O mixtures in the Stanford High-Pressure Shock Tube (HPST). Experiments were conducted at gas Temperatures and pressures between 600-2200 K and 2-22 atm, respectively.

Pavel A. Strizhak - One of the best experts on this subject based on the ideXlab platform.

  • Evaporation of Water in the Process of Movement of its Large Masses Through a High-Temperature Gas Medium
    Journal of Engineering Physics, 2020
    Co-Authors: Alena O. Zhdanova, Geniy V. Kuznetsov, Pavel A. Strizhak
    Abstract:

    A numerical investigation of the heat transfer in large monolithic water masses and water masses with different spaces filled with water vapor and Gases, moving through High-Temperature Gases at Temperatures Higher than 1000 K under the conditions of phase transformations, has been performed. The completeness of evaporation of the water from a water mass moving in a High-Temperature gas medium was numerically estimated with account for the degree of inhomogeneity of the water mass.

  • Droplet evaporation in water jet at the motion through High Temperature Gases
    MATEC Web of Conferences, 2020
    Co-Authors: Pavel A. Strizhak, Roman S. Volkov, Elena Yu. Kurilenko
    Abstract:

    Heat and mass transfer model for the numerical investigation of the evaporation process of a single droplet in water jet when moving through High Temperature Gases was developed. The integral characteristics of the process under investigation were calculated. The macroscopic regularities of water droplet evaporation, as elements of jet, in the High Temperature gas mixture (as exemplified by combustion products of typical condensed substances) were determined.

  • experimental estimation of evaporation rates of water droplets in High Temperature Gases
    Journal of Applied Mechanics and Technical Physics, 2017
    Co-Authors: R. S. Volkov, G. V. Kuznetsov, V E Nakoryakov, Pavel A. Strizhak
    Abstract:

    Evaporation rates of water droplets in High-Temperature Gases were experimentally determined using High-speed video recording cameras and low-inertia thermocouples (for heated air flow as an example). The experiments were carried out for droplets of initial size (radius) 1–3 mm at an air Temperature of 500–1000 K. Dependences of the evaporation rate of water droplets on time and gas Temperature were obtained for various initial droplet sizes.

  • Experimental investigation of consecutive water droplets falling down through High-Temperature gas zone
    International Journal of Heat and Mass Transfer, 2016
    Co-Authors: Roman S. Volkov, Geniy V. Kuznetsov, Jean Claude Legros, Pavel A. Strizhak
    Abstract:

    Abstract An experimental investigation of the motion of water droplets falling down in series of 2, 3 and 4 through High-Temperature gas (about 1100 K) was carried out. Sizes of droplets (radii 1–3 mm), initial distances between them (4–36 mm), initial speeds (0.5–2 m/s), as well as up-flow gas velocities (1.5 m/s) are varied within ranges corresponding to some advanced applications. Velocities and evaporation rates of each droplet were measured by High-speed video camera “Phantom” (up to 105 frames per second), associated with the software packages “Tema Automotive” and “Phantom Camera Control” while varying the distance between droplets within wide range. Conditions for coalescence of droplets, their slowing down and acceleration in High-Temperature Gases were determined. Influence of the initial droplet sizes, the distance between droplets, their Temperatures as well as their number during motion in an upstream flux of High-Temperature Gases on the intensification of evaporation was analyzed. One of the most typical mechanisms of droplet coalescence in High-Temperature gas zone was experimentally confirmed.

  • Regularities in Evaporation and Carryover of Polydisperse Water Flow Droplets During Motion Through High-Temperature Gases
    Chemical and Petroleum Engineering, 2015
    Co-Authors: G. V. Kuznetsov, Pavel A. Strizhak, R. S. Volkov
    Abstract:

    The macroscopic regularities of the motion of water droplets (initial size 50–500 μm) moving through a counter-flowing High-Temperature gas at about 1100 K were investigated using panoramic tracer visualization optical methods (Particle Image Velocimetry and Interferometric Particle Imaging). Characteristic velocities of water droplet evaporation, as well as conditions for their retardation and subsequent carryover by High-Temperature Gases, were determined. The limiting initial velocities and sizes of droplets for which the conditions of retardation and carryover are implemented were established. Recommendations for improvement of the effectiveness of thermal (High-Temperature) water cleaning were formulated.

G. V. Kuznetsov - One of the best experts on this subject based on the ideXlab platform.

  • evaporation of water droplets moving through High Temperature Gases
    Journal of Engineering Physics, 2018
    Co-Authors: G. V. Kuznetsov, P A Strizhak
    Abstract:

    With the use of High-speed recording and diagnostic facilities, an experimental study has been made of the evaporation of droplets (of characteristic size Rm ≈ 0.05–0.035 mm) of atomized flow of water-based suspensions with typical soil impurities (silt and clay) moving in a High-Temperature (about 1100 K) gaseous medium (with the example of acetone combustion products). The relative mass concentration of soil components in the suspension was varied over the range of γ = 0–1%. A strong influence of the above impurities on the main characteristic of evaporation — the relative change in the droplet radius ΔR — has been established. The influence of the initial Temperature (varied over the range of Tw = 278–320 K) of the atomized suspension on the evaporation rate of the latter has been determined. It has been shown that the values of integral characteristics of the process of evaporation of suspensions with soil impurities can be much (2–3 times) Higher than for water without these components.

  • experimental estimation of evaporation rates of water droplets in High Temperature Gases
    Journal of Applied Mechanics and Technical Physics, 2017
    Co-Authors: R. S. Volkov, G. V. Kuznetsov, V E Nakoryakov, Pavel A. Strizhak
    Abstract:

    Evaporation rates of water droplets in High-Temperature Gases were experimentally determined using High-speed video recording cameras and low-inertia thermocouples (for heated air flow as an example). The experiments were carried out for droplets of initial size (radius) 1–3 mm at an air Temperature of 500–1000 K. Dependences of the evaporation rate of water droplets on time and gas Temperature were obtained for various initial droplet sizes.

  • experimental study of the effects of collision of water droplets in a flow of High Temperature Gases
    Journal of Engineering Physics, 2016
    Co-Authors: D V Antonov, G. V. Kuznetsov, R. S. Volkov, P A Strizhak
    Abstract:

    Using High-speed video recording and cross-correlation "tracer" visualization, the authors have investigated the regularities of the processes of collision of water droplets (characteristic parameters: radii 0.025–0.25 mm, velocities of motion 0.5–12 m/s, and relative concentration 0.001–0.0012 m3 of liquid droplets in 1 m3 of the gas) in their motion in a flow of High-Temperature (about 1100 K) Gases. The characteristic effects of collision of two droplets, at which combined droplets are formed (coagulation occurs) and conditions for spreading or fragmentation of the latter are implemented, have been singled out. The values of the Weber and Reynolds numbers for droplets before and after the collisions have been established. The influences of the velocities of motion, the dimensions, and the angles of intersection of mechanical trajectories of droplets on the effects of collisions have been determined.

  • effect of the volume concentration of a set of water droplets moving through High Temperature Gases on the Temperature in the wake
    Journal of Applied Mechanics and Technical Physics, 2015
    Co-Authors: G. V. Kuznetsov, P A Strizhak
    Abstract:

    The processes of heat and mass transfer and phase transformations during motion of a set of water droplets through High-Temperature Gases have been studied numerically. The regimes and conditions of formation of zones of significant joint influence of the droplets on the integral characteristics of heat and mass transfer are determined. The values of the dimensionless parameters describing the dependence of the Temperature of the Gases in the wake of a small set droplets on their volume concentration and arrangement are calculated. The variations in these dimensionless parameters during motion of droplets through High-Temperature Gases are described.

  • Regularities in Evaporation and Carryover of Polydisperse Water Flow Droplets During Motion Through High-Temperature Gases
    Chemical and Petroleum Engineering, 2015
    Co-Authors: G. V. Kuznetsov, Pavel A. Strizhak, R. S. Volkov
    Abstract:

    The macroscopic regularities of the motion of water droplets (initial size 50–500 μm) moving through a counter-flowing High-Temperature gas at about 1100 K were investigated using panoramic tracer visualization optical methods (Particle Image Velocimetry and Interferometric Particle Imaging). Characteristic velocities of water droplet evaporation, as well as conditions for their retardation and subsequent carryover by High-Temperature Gases, were determined. The limiting initial velocities and sizes of droplets for which the conditions of retardation and carryover are implemented were established. Recommendations for improvement of the effectiveness of thermal (High-Temperature) water cleaning were formulated.

P A Strizhak - One of the best experts on this subject based on the ideXlab platform.

  • evaporation of water droplets moving through High Temperature Gases
    Journal of Engineering Physics, 2018
    Co-Authors: G. V. Kuznetsov, P A Strizhak
    Abstract:

    With the use of High-speed recording and diagnostic facilities, an experimental study has been made of the evaporation of droplets (of characteristic size Rm ≈ 0.05–0.035 mm) of atomized flow of water-based suspensions with typical soil impurities (silt and clay) moving in a High-Temperature (about 1100 K) gaseous medium (with the example of acetone combustion products). The relative mass concentration of soil components in the suspension was varied over the range of γ = 0–1%. A strong influence of the above impurities on the main characteristic of evaporation — the relative change in the droplet radius ΔR — has been established. The influence of the initial Temperature (varied over the range of Tw = 278–320 K) of the atomized suspension on the evaporation rate of the latter has been determined. It has been shown that the values of integral characteristics of the process of evaporation of suspensions with soil impurities can be much (2–3 times) Higher than for water without these components.

  • experimental study of the effects of collision of water droplets in a flow of High Temperature Gases
    Journal of Engineering Physics, 2016
    Co-Authors: D V Antonov, G. V. Kuznetsov, R. S. Volkov, P A Strizhak
    Abstract:

    Using High-speed video recording and cross-correlation "tracer" visualization, the authors have investigated the regularities of the processes of collision of water droplets (characteristic parameters: radii 0.025–0.25 mm, velocities of motion 0.5–12 m/s, and relative concentration 0.001–0.0012 m3 of liquid droplets in 1 m3 of the gas) in their motion in a flow of High-Temperature (about 1100 K) Gases. The characteristic effects of collision of two droplets, at which combined droplets are formed (coagulation occurs) and conditions for spreading or fragmentation of the latter are implemented, have been singled out. The values of the Weber and Reynolds numbers for droplets before and after the collisions have been established. The influences of the velocities of motion, the dimensions, and the angles of intersection of mechanical trajectories of droplets on the effects of collisions have been determined.

  • effect of the volume concentration of a set of water droplets moving through High Temperature Gases on the Temperature in the wake
    Journal of Applied Mechanics and Technical Physics, 2015
    Co-Authors: G. V. Kuznetsov, P A Strizhak
    Abstract:

    The processes of heat and mass transfer and phase transformations during motion of a set of water droplets through High-Temperature Gases have been studied numerically. The regimes and conditions of formation of zones of significant joint influence of the droplets on the integral characteristics of heat and mass transfer are determined. The values of the dimensionless parameters describing the dependence of the Temperature of the Gases in the wake of a small set droplets on their volume concentration and arrangement are calculated. The variations in these dimensionless parameters during motion of droplets through High-Temperature Gases are described.

  • influence of radiative heat and mass transfer mechanism in system water droplet High Temperature Gases on integral characteristics of liquid evaporation
    Thermal Science, 2015
    Co-Authors: Dmitrii O Glushkov, G. V. Kuznetsov, P A Strizhak
    Abstract:

    Physical and mathematical (system of differential equations in private derivatives) models of heat and mass transfer were developed to investigate the evaporation processes of water droplets and emulsions on its base moving in High-Temperature (more than 1000 K) gas flow. The model takes into account a conductive and radiative heat transfer in water droplet and also a convective, conductive and radiative heat exchange with High-Temperature gas area. Water vapors characteristic Temperature and concentration in small wall-adjacent area and trace of the droplet, numerical values of evaporation velocities at different surface Temperature, the characteristic time of complete droplet evaporation were determined. Experiments for confidence estimation of calculated integral characteristics of processes under investigation - mass liquid evaporation velocities were conducted with use of cross-correlation recording video equipment. Their satisfactory fit (deviations of experimental and theoretical velocities were less than 15%) was obtained. The influence of radiative heat and mass transfer mechanism on characteristics of endothermal phase transformations in a wide Temperature variation range was established by comparison of obtained results of numerical simulation with known theoretical data for “diffusion” mechanisms of water droplets and other liquids evaporation in gas.

  • influence of the initial parameters of spray water on its motion through a counter flow of High Temperature Gases
    Technical Physics, 2014
    Co-Authors: R. S. Volkov, G. V. Kuznetsov, P A Strizhak
    Abstract:

    The motion of spray water through a counter flow of High-Temperature Gases is experimentally studied on a macroscopic level using optical techniques for diagnostics of two-phase liquid-gas and vapor-liquid flows. It is found that the initial Temperature, concentration of typical impurities, and dispersity of water influence the component composition of the forming gas-vapor-droplet mixture. The integral characteristics of evaporation of solitary droplets with initial sizes (conditional characteristic radii) of 3–5 mm and a spray water flow with droplets less than 0.5 mm across through a High-Temperature gaseous medium are compared.

R. S. Volkov - One of the best experts on this subject based on the ideXlab platform.

  • experimental estimation of evaporation rates of water droplets in High Temperature Gases
    Journal of Applied Mechanics and Technical Physics, 2017
    Co-Authors: R. S. Volkov, G. V. Kuznetsov, V E Nakoryakov, Pavel A. Strizhak
    Abstract:

    Evaporation rates of water droplets in High-Temperature Gases were experimentally determined using High-speed video recording cameras and low-inertia thermocouples (for heated air flow as an example). The experiments were carried out for droplets of initial size (radius) 1–3 mm at an air Temperature of 500–1000 K. Dependences of the evaporation rate of water droplets on time and gas Temperature were obtained for various initial droplet sizes.

  • experimental study of the effects of collision of water droplets in a flow of High Temperature Gases
    Journal of Engineering Physics, 2016
    Co-Authors: D V Antonov, G. V. Kuznetsov, R. S. Volkov, P A Strizhak
    Abstract:

    Using High-speed video recording and cross-correlation "tracer" visualization, the authors have investigated the regularities of the processes of collision of water droplets (characteristic parameters: radii 0.025–0.25 mm, velocities of motion 0.5–12 m/s, and relative concentration 0.001–0.0012 m3 of liquid droplets in 1 m3 of the gas) in their motion in a flow of High-Temperature (about 1100 K) Gases. The characteristic effects of collision of two droplets, at which combined droplets are formed (coagulation occurs) and conditions for spreading or fragmentation of the latter are implemented, have been singled out. The values of the Weber and Reynolds numbers for droplets before and after the collisions have been established. The influences of the velocities of motion, the dimensions, and the angles of intersection of mechanical trajectories of droplets on the effects of collisions have been determined.

  • Regularities in Evaporation and Carryover of Polydisperse Water Flow Droplets During Motion Through High-Temperature Gases
    Chemical and Petroleum Engineering, 2015
    Co-Authors: G. V. Kuznetsov, Pavel A. Strizhak, R. S. Volkov
    Abstract:

    The macroscopic regularities of the motion of water droplets (initial size 50–500 μm) moving through a counter-flowing High-Temperature gas at about 1100 K were investigated using panoramic tracer visualization optical methods (Particle Image Velocimetry and Interferometric Particle Imaging). Characteristic velocities of water droplet evaporation, as well as conditions for their retardation and subsequent carryover by High-Temperature Gases, were determined. The limiting initial velocities and sizes of droplets for which the conditions of retardation and carryover are implemented were established. Recommendations for improvement of the effectiveness of thermal (High-Temperature) water cleaning were formulated.

  • experimentally determining the sizes of water flow droplets entrained by High Temperature Gases
    Thermal Engineering, 2015
    Co-Authors: R. S. Volkov, G. V. Kuznetsov, A O Zhdanova, Pavel A. Strizhak
    Abstract:

    Regularities pertinent to counter mixing of the flows of High-Temperature (1000 K) Gases and water (with the characteristic droplet sizes from 0.05 to 0.5 mm) are experimentally investigated using High-speed (105 snapshots per second) cross-correlation video recording equipment and panoramic optic digital “tracer” visualization methods (called the Particle Image Velocimetry and Interferometric Particle Imaging techniiques). The sizes of droplets entrained by High-Temperature Gases and their motion velocities acquired after having been mixed with Gases (with the gas motion velocities varied in the range of 0.1–2.5 m/s) are established. The initial droplet motion velocities were varied from 0.5 to 5.0 m/s. Two characteristic water droplet motion modes in the counter flow of High-Temperature Gases under the conditions of intense phase transformations were established. It is demonstrated that the droplet motion pattern in the counter flow of High-Temperature Gases, as well as the droplet evaporation intensity depend in the main on the initial sizes of liquid droplets. The integral dependence Redr = f(Reg) using which it is possible to predict the droplet motion modes and trajectories, as well as phase transformation intensity with the a priori known droplet sizes and steam-droplet and gas flow velocities is obtained.

  • influence of the initial parameters of spray water on its motion through a counter flow of High Temperature Gases
    Technical Physics, 2014
    Co-Authors: R. S. Volkov, G. V. Kuznetsov, P A Strizhak
    Abstract:

    The motion of spray water through a counter flow of High-Temperature Gases is experimentally studied on a macroscopic level using optical techniques for diagnostics of two-phase liquid-gas and vapor-liquid flows. It is found that the initial Temperature, concentration of typical impurities, and dispersity of water influence the component composition of the forming gas-vapor-droplet mixture. The integral characteristics of evaporation of solitary droplets with initial sizes (conditional characteristic radii) of 3–5 mm and a spray water flow with droplets less than 0.5 mm across through a High-Temperature gaseous medium are compared.