High Energy PLIF Measurement System

• Subject Area: Fluid Mechanics, Technical Thermodynamics and Thermal Energy Engineering
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 525040175

The Lehrstuhl für Öptische Messverfahren für die Energie- und Verfahrenstechnik is a new research group being established at the RWTH Aachen University. The focus of the group is to develop and apply laser and optical measurement techniques for the study of problems of fundamental and applied scientific interest in the field of energy- and process engineering. The goal of this proposal to acquire instrumentation necessary to successfully undertake planned research projects. It is proposed to acquire a laser-based imaging system for use in the spectroscopic measurement technique “planar laser-induced fluorescence” (PLIF) imaging. PLIF is a non-intrusive, laser-based imaging technique that enables a user to capture 2-dimensional, planar images of specific chemical species in a flow. It accomplishes this by using a laser (spread into a 2-dimensional sheet) to excite a specific atom or molecule from a low-energy quantum state to a high-energy one, and imaging the fluorescence emission generated as the atoms or molecules return to the ground state. With appropriate calibration, the PLIF technique yields valuable information on the spatial distribution, number density, temperature and other physical parameters of chemical species in liquid- and gaseous flows. The PLIF measurement system to be acquired is designed to enable the application of PLIF in a variety of experimental configurations. These include A) simultaneous imaging of two chemical species in a high temperature reacting flow, B) simultaneous imaging of a single chemical species in two (parallel- or intersecting-) planes, C) two-shot imaging of a single chemical species to track rapidly developing phenomena such as growth of an ignition kernel, and D) excitation of two different molecular transitions in a single chemical species in order to extract flow temperature via modelling of the Boltzmann distribution. The measurement apparatus to be acquired will consist of two frequency-doubled dye lasers, two intensified cameras and necessary support components such as data-acquisition and control software and timing/triggering systems. The dye lasers will be pumped using flashlamp-pumped solid state lasers. The solid-state lasers will be injection-seeded to ensure narrow line-width necessary for efficient sum-frequency mixing. These components will be integrated into a system, to be delivered by a single vendor.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Hochenergie PLIF Messsystem
• Instrumentation Group: 8860 Geschwindigkeitsmeßgeräte (außer 047, 053, 192 und 244)
• Applicant Institution: Rheinisch-Westfälische Technische Hochschule Aachen
• Leader: Professor Dr. Isaac Boxx