Valeri Kirsch

Valeri Kirsch
Carl Zeiss AG

Doctor of Engineering

About

22
Publications
3,248
Reads
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69
Citations
Citations since 2016
18 Research Items
68 Citations
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2016201720182019202020212022051015
Introduction
„See first, think later, then test. But always see first. Otherwise you will only see what you were expecting. Most scientists forget that.“ — Douglas Adams
Additional affiliations
January 2020 - present
RWTH Aachen University
Position
  • PhD Student
July 2014 - December 2019
RWTH Aachen University
Position
  • Research Assistant
June 2014 - March 2015
RWTH Aachen University
Position
  • Research Assistant

Publications

Publications (22)
Conference Paper
Full-text available
In-cylinder mixture formation and combustion are highly influenced by primary breakup of injected fuel. Experimentalinvestigation of this phenomenon directly at the outlet of a diesel injector requires a specialized transmitted light microscopy technique combined with a constant-pressure flow microscopy vessel. The method allows verification of the...
Preprint
Full-text available
A novel transparent direct injection nozzle concept is used to simultaneously visualize nozzle-internal flows and external primary breakup with transmitted light microscopy. Fused silica enables manufacturing of precise 3D internal nozzle geometries with a few micrometer accuracy based on the selective laser etching. To avoid interaction of the met...
Preprint
Full-text available
A new design for transparent high-pressure nozzles is presented in this work. This new design enables using the innovative Selective Laser Etching (SLE) method to manufacture transparent nozzles with outstanding accuracy. Therefore, not only the simultaneous visualization of the flow mechanics inside and outside the nozzle is enabled, but the manuf...
Article
Full-text available
This work presents “pulsed 2D-3cLIF-EET” as a measurement setup for micro-droplet internal temperature imaging. The setup relies on a third color channel that allows correcting spatially changing energy transfer rates between the two applied fluorescent dyes. First measurement results are compared with results of two slightly different versions of...
Conference Paper
Full-text available
E-fuels based on renewable electricity and carbon sources from CO2 have gained much attention in recent years due to ever-increasing stringent emission regulations. Some of these e-fuels have high vapor pressure, which makes them more prone to flash boiling for some operating conditions. In this work, the flash boiling phenomenon of these novel e-f...
Conference Paper
Full-text available
Within the Cluster of Excellence – “The Fuel Science Center,” concerted efforts are being made to develop novel e-fuels based on renewable energy and CO2 as carbon sources. Some of these fuels are highly susceptible to flash boiling at low-pressure conditions. In this study, the flash boiling phenomenon of these e-fuels is numerically investigated...
Conference Paper
Full-text available
Within the Cluster of Excellence - “The Fuel Science Center,” we develop a predictive simulation process for the screening of novel bio-hybrid fuel candidates. Beginning from the molecular structure of the fuel, the thermo-physical properties are predicted, which are then used in a spray model to predict mixing. The ignition delay times and emissio...
Article
Full-text available
The relatively new thermometry technique “pulsed 2cLIF with MDR-enhanced energy transfer” is tested for the first time on micro-droplet streams in a heated air flow. The method allows simultaneous measurements of the droplet internal temperature-field, droplet size and droplet velocity. Plausibility of the measurement results is evaluated by compar...
Article
Full-text available
A new measurement system called “pulsed 2D-2cLIF-EET” has been developed to study temperature fields inside micro-droplets. Pulsed fluorescence excitation allows motion blur suppression and thus simultaneous measurement of droplet size and temperature. Occurrence of morphology-dependent resonances and subsequent stimulated dye emission are accounte...
Conference Paper
Full-text available
A new method for instantaneous measurement of temperature, size and velocity of micro-droplets has been developed.The method is based on the well-known 2-color laser-induced fluorescence (2cLIF) technique, but usesa pulsed laser for 2-dimensional imaging without motion blur and an adjusted dye mixture for suppression of LIFMDRsby utilizing the MDR-...
Chapter
Zur stetigen Optimierung motorischer Brennverfahren sind zwei grundlegende Maßnahmen geeignet: eine Anpassung der motorischen Randbedingungen (wie Geometrie, Ventilstellungen, Einspritzstrategien etc.) oder eine Optimierung der Kraftstoffzusammensetzung. Kraftstoffvariationen haben hohes Potential zur Emissionsminderung, da durch Veränderung der ch...
Article
A microscopic system, consisting of a transmitted light microscope and constant-pressure flow vessel, is specifically designed to enable highly resolved high-pressure primary breakup investigations at engine-like densities. At first mea-surements diesel and two alternative fuels are injected with a standard diesel injector at different ambient pres...
Article
Full-text available
In this work, a new measurement system is presented for studying temperature of micro-droplets by pulsed 2-color laser-induced fluorescence. Pulsed fluorescence excitation allows motion blur suppression and thus simultaneous measurements of droplet size, velocity and temperature. However, high excitation intensities of pulsed lasers lead to morphol...
Conference Paper
The underlying physics of jet breakup is hardly understood due to lack of experimental data. Especially in case of increased ambient densities, optical techniques suffer from obstruction of transmitted light in the near field of optically dense sprays. The inner jet region cannot be analyzed on the basis of conventional highly resolving microscopic...
Conference Paper
Full-text available
The development of new fuels from biomass is one promising technology for future energy supply. In the design process, the mixing efficiency of such novel biofuels needs to be characterized. The analysis of the impact of flow structures down to the characteristic length scales allows to qualitatively and quantitatively assess combus- tion efficienc...
Conference Paper
Full-text available
Even though the atomization process is in focus of spray research for decades, the impact of superimposed mechanisms on the development of primary liquid structures is hardly understood for engine relevant conditions. Especially the impact of variable ambient density on primary breakup is still unclear, since well-founded data on primary liquid str...

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Cited By

Projects

Project (1)
Project
Establish innovative and sustainable processes for the conversion of whole plants into fuels which are tailor-made for novel low-temperature combustion engine processes with high efficiency and low pollutant emissions, paving the way to the 3rd generation of biofuels.