Liquid LIF system

Measurement of velocity, concentration and temperature in liquid flows using Laser Induced Fluorescence

Concentration measurements in liquid flows

Dantec Dynamics' liquid planar-LIF system is an optical measurement tool to acquire whole-field concentration data using the planar laser-induced fluorescence (planar-LIF) technique. Quantitative analysis is based on calibration images that map the response at every pixel of the camera with respect to both local concentration and local laser light energy.

Applications

With Dantec Dynamics' planar-LIF solutions, quantitative information can be obtained in many concentration applications, including:

• The mixing performance of e.g. chemical processes
  
  
• The role of coherent mixing structures on the transport of a marker
  
  
• The interaction between large-scale and smaller-scale in turbulent mixing
  
  
• The dispersion of pollutants in model ocean systems, etc.

Synchronised velocity/concentration measurements

A liquid planar-LIF system can combine planar laser-induced fluorescence with particle image velocimetry (PIV) to get whole-field synchronised velocity and concentration data in liquid flows. The methodology is ideal for acquiring experimental information on the physics of mixing in the flow.

The solution features:

• Combination of flow visualisation with accurate quantitative analysis
  
  
• Statistical analysis of concentration and velocity measurements
  
  
• Investigation of scalar transport through Reynolds fluxes (see illustration below)

Working principles

The liquid flow is seeded with small tracer particles and a fluorescent marker is injected at a given position in the flow to give the PIV and LIF signals respectively. The system separates and samples the two signals simultaneously: the PIV camera (equipped with a filter corresponding to the laser wavelength) detects particle displacement and the LIF camera (equipped with a filter corresponding to the wave of fluorescence) detects the fluorescence levels in the liquid.

The system then processes the PIV and LIF images into instant whole-field velocity and concentration maps. Additional methods may be applied to further process the data.

Temperature measurements

Dantec Dynamics' liquid Planar-LIF solution can also be used to acquire whole-field temperature data. Quantitative analyses are based on temperature calibration images that map the response at every pixel of the camera with respect to local temperature (and local laser light energy if required).

Applications

With this technique, quantitative information can be obtained on:

• Heat transfer phenomena in heat exchangers, pumps and other devices for e.g. improvement of apparatus performance and equipment design
  
  
• Temperature distribution in fluids of engineering interests such as foodstuffs, paints, etc.

Synchronised velocity/temperature measurements

The liquid Planar-LIF system can naturally combine temperature planar laser-induced fluorescence with particle image velocimetry (PIV) to get whole-field synchronised velocity and temperature data in liquid flows. The methodology is ideal for acquiring fundamental information on the physics of heat transfer (without mixing) in various flow configurations.

The system features:

• Built-in calibration methods for temperature and laser energy
  
  
• Precise and accurate analyses of instant temperature and velocity fields (see illustration below)
  
  
• Statistical analysis of temperature and velocity measurements

Working principles