Accession Number : ADA263810

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

Corporate Author : WISCONSIN UNIV-MADISON ENGINE RESEARCH CENTER

Personal Author(s) : Giangregorio, Roberto P. ; Zhu, Yuanxian ; Reitz, Rolf D.

Report Date : 05 MAR 1993

Pagination or Media Count : 17

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.

Descriptors :   *TEMPERATURE, *DIESEL ENGINES, *TURBULENT DIFFUSION, AIR, COMBUSTION CHAMBERS, DIFFUSIVITY, HIGH ENERGY, HOT SPOTS, IONIZATION, LASER BEAMS, LASERS, MONITORING, PROPAGATION, PULSED LASERS, SHOCK, SHOCK WAVES.

Subject Categories : Fluid Mechanics
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE