Analytical Technologies Singapore

LaVision

LaVision published a paper about the novel Object-aware Lagrangian Particle Tracking (OA-LPT) scheme in the Measurement Science and Technology journal

The measurement of flows around objects such as cars, airfoils and maritime structures often poses major challenges for optical flow diagnostics methods such as Tomo-PIV or Lagrangian Particle Tracking (LPT)/Shake-the-Box (STB) within the measurement fields. Also, many flow reconstruction algorithms simply do not have the capabilities of incorporating such object information.


For this reason, measurements are often limited to observations directly behind the object (characterization of wake flows) or to the stitching of averaged flow fields in sub-sampled regions in order to avoid having negative impacts on the measurement data.


To solve this practical problem, LaVision introduces the novel Object-aware Lagrangian Particle Tracking (OA-LPT) method to seamlessly integrate the knowledge about the presence of view-obstructing objects in the measurement domain during the 3D particle reconstruction.
It minimizes the occurrence of reconstruction artifacts and provides a measurement approach for instantaneous 360° LPT/STB measurements around the objects of interest.

LaVision published a paper about the novel Object-aware Lagrangian Particle Tracking (OA-LPT) scheme in the Measurement Science and Technology journal Read More »

LaVision launches the next generation of PIV cameras – the Imager CX3p Camera Series!

All the advantages of the Imager CX3 camera series, which was successfully introduced last year, were the basis for this further development.

The small and compact cameras of the Imager CX3 camera series, which are equipped with the innovative back-illuminated technology that enables incredible sensitivity and very low noise, have already been a resounding sales success. The small pixels enable very small fields of view for a given lens, and the hardware binning guarantees exceptional frame rates and therefore increased flexibility when using these cameras.

LaVision is now launching the unique Imager CX3p camera series, which is equipped with an integrated Scheimpflug mount for adjusting the angle between camera and lens (Scheimpflug angle) for C-mount and F-mount lenses.This ensures quick and easy alignment of the viewing direction, Scheimpflug angle and sensor orientation.

The integrated Scheimpflug mount offers three independent setting options for tilt, rotation and sensor orientation. All settings are supported by an intuitive DaVis software tool resulting in very quick and easy Scheimpflug adjustment.

Here you can watch our video, showing the easy handling of this camera with all its Scheimpflug settings as well as the adjustment of the Scheimpflug mount supported by our user-friendly DaVis software tool.

LaVision launches the next generation of PIV cameras – the Imager CX3p Camera Series! Read More »

FlameMaster Setup & Installation

Testing of the measurement of flame temperature using FlameMaster
Calibration setup using a filament lamp

LaVision’s Two-Color Pyrometry setup provides a robust system for temperature measurements. It demonstrates the precise measurement of flame temperature, showcasing the system’s accuracy and capability. Additionally, the calibration process is conducted using a filament lamp, ensuring the system’s reliability and accuracy through meticulous calibration procedures.

LaVision Flamemaster Software

The FlameMaster inspex imaging systems apply flame emission spectroscopy to combustion processes.

​The flame emission (chemiluminescence) of flame radicals like OH*, CH*, C2* is used to e.g. visualise the reaction zone or to monitor flame stoichiometry via emission ratios of such radicals. 2-colour pyrometry (blackbody radiation) is used to measure temperature fields in sooty flames.

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Laser Doppler Velocimetry (LDV)

Laser Doppler Velocimetry (LDV) is a technique which allows the measurement of velocity at a point in a flow field with a high temporal resolution. Whenever a micron-sized liquid or solid particle entrained in a fluid passes through the intersection of two laser beams, the scattered light received from the particles fluctuates in intensity.
 
Laser Doppler Velocimetry (LDV) makes use of the fact that the frequency of this fluctuation is equivalent to the Doppler shift between the incident and scattered light, and is thus proportional to the component of particle velocity which lies in the plane of two laser beams.

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Rayleigh scattering

Rayleigh scattering is the elastic scattering of light by particles much smaller than the wavelength of the light. That is the case for gas phase molecules and, therefore, this method is suited for laser imaging in gases. Rayleigh scattering of sunlight by atmospheric molecules is the reason for the observed blue colour of the sky, because the scattering efficiency varies inversely with the fourth power of the wavelength. 

For a single component gas with known scattering cross section the Rayleigh signal is directly proportional to the gas density. The scattered light is almost at the same wavelength as the incident light, i. e. Rayleigh scattering is not species selective. Rayleigh scattering requires either constant gas composition or known mole fractions of all major species for the density measurement of a gas mixture. In some cases Rayleigh scattering is stronger for one species than another, and it can be used to image mixing processes such as fuel – air mixing.

When gas composition and pressure are known Rayleigh imaging allows to measure planar temperature fields (Rayleigh Thermometry). Rayleigh scattering is much weaker than Mie scattering but more than two orders of magnitude stronger than Spontaneous Raman Scattering. Incandescence from soot and Mie scattering are processes that can totally obscure the Rayleigh signal.

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Interferometric Mie Imaging

IMI imaging of single droplets

Interferometric Mie Imaging (IMI) is a sizing technique for the evaluation of the diameter of spherical particles, droplets and bubbles similar to PDI. The working principle is based on the out-of-focus imaging of particles illuminated by a laser light sheet. The optical setup of a standard IMI system consists of a laser-light sheet and a digital camera with a high quality lens. Moving the camera chip to an out-of-focus position an interference fringe pattern becomes visible.

The visible fringe pattern corresponds exactly to the far field scattering which can be calculated by the Mie theory. The number of fringes within the aperture image depends on the diameter of the droplet and the aperture angle. With increasing particle size, the number of fringes increases. The exact size of the particles is determined by analysis of the fringe patterns. The size of the aperture image is a measure for the z-position of the particle along the line-of-sight.

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