Liquid crystal test rig


At the liquid crystal test rig of the Institute of Thermal Fluid Machinery, investigations are carried out into the quantitative measurement of wall shear stresses using liquid crystals(research focus: wall shear stress measurement using liquid crystal technology).


Figure 1: Test stand with illumination and camera


  • Large-area, high-resolution, quantitative measurement of wall shear stresses
  • Isolated investigation of numerous parameters on the selectively scattered color signal of the liquid crystals
  • Visualization of boundary layer phenomena
  • Top-light/top-view mode and back-light/back-view mode
  • Application of different optical measurement methods
  • Max. Max. air mass flow: 2.7 kg/s with a max. pressure ratio of up to 1.5
  • Max. Air temperature: adjustable in the range 308 K - 330 K
  • Fully automated data acquisition

Measurement technology & control

  • Measurement of velocity and temperature profiles using miniaturized combined Pitot thermocouple probe
  • Measurement of static pressures using pressure transducers
  • Measurement of surface temperatures using embedded thermocouples
  • Visualization of boundary layer phenomena using liquid crystals
    • BCN192
    • CN/R3
    • CN/R2
  • Data acquisition of shear stress-associated color changes using a commercial camera
  • Data acquisition and test stand control using NI LabVIEW and Beckhoff PLC