Application of Schlieren Optical Techniques for the Measurement of Gas Temperature and Turbulent Diffusivity in a Diesel Engine,

Abstract

A new technique which is based on optoacoustic phenomena has been developed for measuring in-cylinder gas temperature and turbulent diffusivity. In the experiments, a high energy Nd:YAG pulsed laser beam was focused to cause local ionization of air at a point in the combustion chamber. This initiates a shock wave and creates a hot spot. The local temperature and turbulent diffusivity are determined by monitoring the shock propagation and the hot spot growth, respectively, with a schlieren photography system. In order to assess the validity and accuracy of the measurements, the technique was also applied to a turbulent jet. The temperature measurements were found to be accurate to within 3%. Results from the turbulent jet measurements also showed that the growth rate of the hot spot diameter can be used to estimate the turbulent diffusivity.... I.C. Engines, Diesel, Temperature measurement, Optics, Schlieren.

Document Details

Document Type
Technical Report
Publication Date
Mar 05, 1993
Accession Number
ADA263810

Entities

People

  • Roberto P. Giangregorio
  • Rolf D. Reitz
  • Yuanxian Zhu

Organizations

  • University of Wisconsin–Madison

Tags

DTIC Thesaurus Topics

  • Chambers
  • Combustion
  • Combustion Chambers
  • Diesel Engines
  • Diffusivity
  • Engines
  • High Energy
  • Hot Spots
  • Laser Beams
  • Measurement
  • Photographic Materials
  • Photography
  • Pulsed Lasers
  • Schlieren Photography
  • Shock Waves

Fields of Study

  • Physics

Readers

  • Fluid Mechanics and Fluid Dynamics.
  • Internal Combustion Engine (ICE) Technology.
  • Optical Physics and Photonics.

Technology Areas

  • Directed Energy