Planar Laser-induced Fluorescence (PLIF) by TSI Inc.

plif-perex.jpg Planar laser-induced fluorescence is an advanced optical measuring method for investigation of scalar fields in liquids and gases (concentration, temperature, pH, composition). It is also employed in spray research where it is known as optical patternation – a method for determination of liquid concentration. Fluorescence-active molecules contained in the fluid are excited with a pulse UV laser as they absorb the light. When recovering their energy level prior to the excitation, they emit light at greater wave length. The intensity of the light emitted corresponds to the volume of the excited molecules, and thus to concentration. Based on the fluorescence image record with a CCD camera, instantaneous distribution of temperature or concentration in a plane can be evaluated. Our department makes use of high performance, custom-made PLIF system produced by TSI Incorporated.


  • high energy pulse Nd:YAG laser, beam energy 80 mJ at 266 nm, 100 mJ at 365 nm and 250 mJ at 532 nm
  • light sheet thickness between 0.5 and 2 mm and width of 100 mm
  • stereoscopic arrangement of CCD cameras with Scheimpflug lens, image resolution 1280 x 1024 pixels
  • image capture frequency up to 10 Hz

Typical applications

  • spray analysis: optical patternation (measurement of liquid concentration and mass flow rates), measurement of Sauter mean diameter in sprays
  • diagnostics of combustion, reactants and products analysis
  • studies on substances mixing, high speed, reactive mixing etc.
  • evaluation of temperature fields in liquids and sprays
  • input data for validation of computational models (CFD)

Provided outcomes

  • instantaneous and averaged (mean and rms) images of concentration and temperature in a plane
  • Sauter mean diameter of droplets in a plane
  • a complete picture of a 3D domain can be obtained by sequential measurement over a number of layers
  • when combined with PIV method, mass flow rates in fluids can be evaluated (the arrangement available at the department)

Related publications

Contact person

Jan Jedelsky, Ph.D., Associate Professor
phone: +420 54114 3266 | e-mail: jedelsky@fme_vutbr_cz

Energy Institute, Department of Thermodynamics and Environmental Engineering
Faculty of Mechanical Engineering, Brno University of Technology
Technicka 2896/2, 616 69 Brno, Czech Republic

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