Aerodynamic Particle Size Measurement by Laser-Doppler Velocimetry PDF Download

Author: James Charles Wilson
Publisher:
ISBN:
Category :
Languages : en
Pages : 468

View

Book Description

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
A method of measuring the aerodynamic diameter of aerosol particles was investigated. The method consists of accelerating particles in a coverging nozzle and measuring their velocities near the exit of th nozzle with a laser--Doppler velocimeter. The experimental studies utilized a test nozzle with a converging angle of approximately 15° and an exit diameter of about .1 cm. The pressure drop across the nozzle was varied from 2.54 to 276 cm of H2O, and particle velocity was observed to vary from approximately 0.5 to 1.0 times the gas velocity at the exit of the nozzle. A theoretical analysis utilized boundary layer theory to predict the velocity of the gas in the nozzle, and then the equations of particle motion were integrated to give the theoretical particle velocities. These values agreed with the experimental values to within a few percent. The effects of nozzle geometry, flow rate, particle density, and particle size were studied using the results of calculations made with dimensionless equations. The velocity of a particle in a given nozzle and flow depends upon the aerodynamic diameter of the particle and the particle density. The geometry and flow can be chosen to minimize the effect of particle density. Assuming that the density of particles in the atmosphere ranges from 1 g/cm3 to 3 g/cm3, the aerodynamic diameter of particles can be measured with an uncertainty of +- 10% in the size range from .5 .mu.m to 10 .mu.m.

Author: Howard Doyle Thompson
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 586

View

Book Description
Contents: A Historical Review of Laser Velocimetry. Developments in Instrumentation, Data Analysis, Combustion Measurements, Measurements in Turbulent Flows, Measurements in Internal Combustion Engines, General Applications, Particle Diagnostics, Wild Card Session, and Panel Discussion.

Author: William Joseph Yanta
Publisher:
ISBN:
Category : Laser Doppler velocimeter
Languages : en
Pages : 104

View

Book Description
Turbulence measurements with a Laser Doppler Velocimeter (LDV) using the dual scatter or differential Doppler mode have been made in a subsonic, fully developed channel flow. The measurements were made using only those light scattering particles occurring naturally in air. Results include mean velocity profiles, turbulence intensities, Reynolds stress distributions and a skewness measurement of the velocity distribution function across the channel. Statistical techniques were used to obtain the various turbulence parameters. Guidelines have been established for the amount of data needed to obtain results with a specified accuracy and confidence level. Measurements have also been made to determine the particle-size distribution. An aerodynamic means was used to determine the size distribution, in contrast to the usual optical procedures. (Modified author abstract).

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
Measurement techniques for in-situ simultaneous measurements of particle size distributions and particle velocities using the dual beam laser Doppler velocimeter (LV) were analytically and experimentally investigated. This investigation examined the different signal characteristics of the LV for determination of particle size and particle velocity, simultaneously. The different size related signal components were evaluated not only singularly but also as simultaneous measurements to determine which characteristic, or combination of characteristics, provided the best measure of particle size. The evaluation concentrated on the 0.5 to 5 .mu.m particle size range, in which the LV light scattering characteristics are complex often non-monotonic functions of the particle size as well as functions of index of refraction, the laser light wavelength, laser intensity and polarization, and the location and response characteristics of the detector. Different components of the LV signal were considered, but analysis concentrated on Doppler phase, visibility and scatter-intensity because they show the greatest promise. These signals characteristics were initially defined analytically for numerous optical configurations over the 0.5 to 5 .mu.m diameter range with 0.1 .mu.m segmentation, for refractive index values from 1.0 to 3.0 with absorptive (imaginary) components varied form 0 to 1.0. Collector orientation and effective f/No., as well as fringe spacing, beam polarization and wavelength, were varied in this analytical evaluation. 18 refs., 42 figs., 5 tabs.

Author: Pramod Kulkarni
Publisher: John Wiley & Sons
ISBN: 0470387416
Category : Science
Languages : en
Pages : 920

View

Book Description
Aerosol Measurement: Principles, Techniques, and Applications Third Edition is the most detailed treatment available of the latest aerosol measurement methods. Drawing on the know-how of numerous expert contributors; it provides a solid grasp of measurement fundamentals and practices a wide variety of aerosol applications. This new edition is updated to address new and developing applications of aerosol measurement, including applications in environmental health, atmospheric science, climate change, air pollution, public health, nanotechnology, particle and powder technology, pharmaceutical research and development, clean room technology (integrated circuit manufacture), and nuclear waste management.

Author: William Joseph Yanta
Publisher:
ISBN:
Category : Aerodynamics, Supersonic
Languages : en
Pages : 64

View

Book Description
Results are presented for an experimental program which investigated the application of an LDV technique in supersonic flows. This paper presents an analysis of the behavior of light-scattering particles in rapidly accelerating or shock decelerated flows, an evaluation of particle production techniques and the results of several velocity measurements. Measurements included the velocity distribution along the nozzle centerline and flow over a diamond airfoil in a Mach 3 tunnel and velocity profiles for a turbulent boundary layer in a Mach 4.8 facility. It is demonstrated that LDV measurements can be made consistently with errors of less than five percent if the particle lag is considered. (Author).

Author: Dana G. Andrews
Publisher:
ISBN:
Category : Doppler effect
Languages : en
Pages : 86

View

Book Description
The intensity of laser light back-scattered from a particle and transmitted by a Fabry-Perot interferometer is used to determine particle-size. The instrument's optics and electronics are calibrated by examining stationary particles of known diameter resting on a non-reflective glass slide. The response of the instrument is determined by comparing measured intensities with theoretical values calculated as a complex function of particle size, refractive index and ray geometry. The results show that the measured intensities do approximate the theoretical variation with particle size and in the range of particle diameters measured (1-10 microns), the error is less than one micron. (Author).

Author: William J. Yanta
Publisher:
ISBN:
Category : Laser Doppler velocimeter
Languages : en
Pages : 240

View

Book Description
Turbulence measurements with a Laser Doppler Velocimeter (LDV) using the dual scatter or differential Doppler mode have been made in a subsonic, fully developed channel flow. The measurements were made using only those light scattering particles occurring naturally in air. Results include mean velocity profiles, turbulence intensities, Reynolds stress distributions and a skewness measurement of the velocity distribution function across the channel. Statistical techniques were used to obtain the various turbulence parameters. Guidelines have been established for the amount of data needed to obtain results with a specified accuracy and confidence level. Measurements have also been made to determine the particle-size distribution. An aerodynamic means was used to determine the size distribution, in contrast to the usual optical procedures. (Modified author abstract).

Author: Naomichi Yamamoto
Publisher: Elsevier
ISBN: 0323859704
Category : Science
Languages : en
Pages : 498

View

Book Description
Fundamentals of Bioaerosols Science: From Physical to Biological Dimensions of Airborne Biological Particles covers both the physical and biological aspects of bioaerosol science. It is assumed that researchers with a physics background are often unfamiliar with the biological aspects (e.g., molecular biology, PCR, and DNA sequencing), and researchers with a biology background are often unfamiliar with the physical aspects (e.g., aerosol physics, air sampling, and aerodynamic diameter) of bioaerosol science. This book aims to bridge the interdisciplinary gap between the fields of bioaerosol science. Fundamentals of Bioaerosols Science include topics such as bioaerosol physical properties, sampling and monitoring methods, analytical methods, control techniques, and relationship to climate. Presents an in-depth explanation of the fundamentals of bioaerosols science Includes an introduction to the latest knowledge and technologies related to bioaerosol science Features interdisciplinary contents that are useful even for those without specialized knowledge