Laser Measurement

  Femto second laser Winandy Femto second laser.

The Institute of Heat and Mass Transfer applies various laser measurement techniques. Engine-related sprays and coal combustion are the main research fields for laser measurements.

For engine-related spray investigations, laser measurements are used to analyze the jet breakup and the mixture formation of fuel and air. Measurements are carried out on microscopic and macroscopic scales. In contrast to other multiphase phenomena, sprays are characterized by very high flow velocities and small scales, which make laser measurement techniques inevitable for the quantification of physical properties. Typical measurement variables are droplet size and velocities, mass fraction and temperature distribution as well as different types of visualizations.

The research field of coal combustion requires laser measurement techniques for a quantification of coal particles in a flame. Moreover, laser measurements are used for an analysis of the combustion emissions. Special feature in this research field is the adaption of the measurement principle to the large scales of the coal combustion chamber.

Measurement techniques

  • Laser Doppler Anemometry (LDA) and Phase Doppler Anemometry (PDA)
  • Laser Correlation Velocimetry (LCV)
  • Particle Image Velocimetry (PIV, Stereo-PIV, High Speed PIV)
  • Mie-scattering visualizations
  • shadowgraphy
  • Raman Spectroscopy
  • Rayleigh
  • Laser Induced Fluorescence (LIF, PLIF,2c-LIF)
  • Ballistic Imaging (BI)
  • Particle size by laser diffraction

Measured Variable

  • droplets/particle size (PDA, laser diffraction)
  • droplet/particle velocity (LDA, PDA)
  • spray jet velocity at nozzle outlet (LCV)
  • flow velocity (PIV)
  • macroscopic and microscopic spray visualizations
  • concentration, mass fraction (Raman, LIF, Rayleigh)
  • temperature (2c-LIF, Raman)
  • visualization of optical dense sprays (BI)