High-speed laser for optical measurement of velocities, concentrations and temperatures

• Subject Area: Fluid Mechanics, Technical Thermodynamics and Thermal Energy Engineering
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576096878

This application is being submitted as part of the DFG's equipment renewal programme. The application is for a high-speed laser that will restore the full functionality of two existing high-speed systems procured under Article 91b GG for measuring velocities, concentrations and temperatures using optical measurement methods. The laser previously used as a light source for these systems is no longer fully operational, despite several complex and costly repairs in recent years. Since these two devices are used by the Lab of Fluid Dynamics and Technical Flows for most of its experimental research projects, a complete failure of the laser would cause major difficulties in fulfilling the project programmes, including an SFB/TR. The time-resolved measurement of velocity, concentration and temperature fields is one of the most important measurement tasks in the field of experimental fluid mechanics. The results then allow turbulent flows, which account for the majority of applications, to be accurately analysed and optimised. Similarly, in multiphase flows, the time-resolved recording of the movements of particles and/or bubbles is of great importance for the optimisation of relevant applications, especially in process engineering. In this context, the proposed high-speed laser will restore the full functionality of two high-speed measurement systems (2D and 3D measurements) already available at the chair, whose use is currently very limited due to an original laser that is now very prone to repair. The existing optical measurement systems allow the time- and location-resolved determination of velocity fields in two or three dimensions (3D3C). For this purpose, particle image velocimetry (PIV) is used, in which particles in the flow are illuminated by a laser and the particle images are recorded with high-speed cameras. The velocities in the flow can then be calculated from these. Laser-induced fluorescence (LIF) is used to investigate mixing and mass transport processes. Here, the high-speed laser is used to excite the fluorescence of tracer substances or fluorescent components of the mixture. This enables the time-resolved analysis of such processes for their understanding and optimisation. Temperature fields can also be measured using fluorescence excitation of temperature-dependent tracer substances. The requested high-speed laser, in conjunction with the existing measurement systems, will thus enable measurements in a variety of different flows (mixing processes, separation processes, wind tunnel, water channel, bubble columns, bulk materials, pulsating flows, etc.) to be investigated quantitatively in 2 and 3 dimensions, in detail and with high temporal resolution.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Hochgeschwindigkeitslaser zur optischen Messung von Geschwindigkeiten, Konzentrationen und Temperaturen (Erneuerung)
• Instrumentation Group: 8860 Geschwindigkeitsmeßgeräte (außer 047, 053, 192 und 244)
• Applicant Institution: Otto-von-Guericke-Universität Magdeburg
• Leader: Professor Dr. Dominique Thévenin