Andreas Dreizler

Andreas Dreizler
Technical University of Darmstadt | TU · Department of Mechanical Engineering (Dept.16)

Prof. Dr. habil.

About

446
Publications
53,729
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
10,329
Citations

Publications

Publications (446)
Article
Full-text available
Electric motors with high-power densities are required for the implementation of electromobility. To achieve this, direct liquid cooling methods are increasingly being considered, in which oil is injected into the motor compartment. This results in a two-phase flow that can be used for efficient cooling. However, the oil, which can also penetrate t...
Conference Paper
Ensuring fire safety in polymeric materials, which are inherently flammable but widely used in various industries, is of significant societal and economic importance. This study is part of a broader effort to understand polymer combustion and flame retardant effectiveness at a fundamental level. A major focus is the behavior of polymers burning alo...
Conference Paper
Several techniques exist to measure the carrier and dispersed phases in multi-phase flows. Particle image velocimetry (PIV) analyzes the carrier phase by cross-correlating particle images, but its resolution is limited by the size of the interrogation window, making it difficult to resolve fine-scale turbulent structures. Particle tracking algorith...
Data
This database contains the averaged temperature histories and peak temperatures of iron particles burning in the TU Darmstadt laminar flow reactor. The database is complementary to a manuscript entailed "Temperature of burning iron microparticles with in-situ resolved initial sizes" that is still under review. The database will be publicly avai...
Article
Full-text available
Polyhedral Bunsen flames, induced by hydrodynamic and thermo-diffusive instabilities, are characterized by periodic trough and cusp cellular structures along the conical flame front. In this study, the effects of flow velocity, hydrogen content, and equivalence ratio on the internal cellular structure of premixed fuel-lean hydrogen/methane/air poly...
Article
Full-text available
In this study, a new design for a 1D gas-phase Raman spectrometer is presented, utilizing two dedicated tracks to image different properties of the measured signal onto a single charge-coupled device (CCD) chip. Two possible configurations are shown: a polarization-separation configuration, which separates the detected Raman signal into s- and p-po...
Article
As the urgency for decarbonization of economies around the world is becoming more pressing, green energy carriers synthesized with renewable energy are emerging as tradable commodities for connecting regions with abundant renewable energy to those with high energy demand. Among the various options, metals – especially iron – have been identified by...
Article
Full-text available
In this study, a method adapted from gas-phase combustion is presented to determine the local laminar burning velocities of iron dust flames. This method is also applicable for non-stationary flames, which presents a notable advantage for metal dust flames, as temporally stationary flames remain a challenge for practical reasons. This approach reli...
Article
In this publication, we demonstrate the extension of our loss‐less library approach previously limited to fitting ro‐vibrational N 2 CARS spectra for thermometry purposes to accurate and efficient fitting of dual‐pump CARS spectra with multiple species. The fundamental reasoning behind the compression approach is to make use of finite resolution ef...
Article
Full-text available
Local fuel–air equivalence ratios, gas phase temperature and $$\hbox {CO}_2$$ CO 2 mole fractions were measured by a combination of laser-induced fluorescence of nitric oxide used as a tracer and dual-pump coherent anti-Stokes Raman spectroscopy in a vertically oriented partially premixed boundary layer flame under laminar flow conditions. By embed...
Article
An optically accessible single-cylinder spark-ignition engine operated under homogeneous, part-load conditions is experimentally investigated using optical and spark diagnostics to evaluate the relationship between the spark, flow, and flame with increasing dilution using several levels of exhaust gas recirculation (EGR). Voltage and current measur...
Article
Full-text available
Chemical energy carriers are crucial for addressing challenges that arise from the time lag, large distances, and temporal fluctuations in renewable energy production, which lead to unbalanced energy production and demand. However, the thermochemical utilization of chemical energy carriers such as solid fuels must be widely decarbonized to achieve...
Article
Full-text available
With technical progress, combustion pressures have been increased over the years, frequently exceeding the critical pressure of the injected fluids. For conditions beyond the critical point of the injected fluids, the fundamental physics of mixing and evaporation processes is not yet fully understood. In particular, quantitative data for validation...
Article
The paper presents multi-parameter high-speed optical diagnostics of single iron particle oxidation in a hot laminar flow consisting of O, HO, CO, and N. Prior to luminous combustion, micron-sized particles are visualized using diffuse-backlight-illumination with high temporal and spatial resolutions, enabling in situ particle sizing. The incandesc...
Article
Storing electrical energy for long periods and transporting it over long distances is an essential task of the necessary transition to a CO2-free energy economy. An oxidation–reduction cycle based on iron and its oxides represents a very promising technology in this regard. The present work assesses the potential of converting an existing modern co...
Preprint
The paper presents multi-parameter high-speed optical diagnostics of single iron particle oxidation in a hot laminar flow consisting of O2 , H2O, CO2 , and N2. Prior to luminous combustion, micron-sized particles are visualized using diffuse-backlight-illumination with high temporal and spatial resolutions , enabling in situ particle sizing. The in...
Article
In this study, a method which allows for causal backtracing of turbulent flow phenomena is suggested. Key events in technical processes based on turbulent mixing can thereby be studied by their detailed temporal and spatial convective history. As a demonstration case for this method, a study of cyclic variations in internal combustion engines is us...
Preprint
Full-text available
In the present work, accurate determination of single-particle ignition is focused on using high-speed optical diagnostics combined with machine learning approaches. Ignition of individual particles in a laminar flow reactor are visualized by simultaneous 10 kHz OH-LIF and DBI measurements. Two coal particle sizes of 90-125{\mu}m and 160-200{\mu}m...
Article
Full-text available
This work presents an experimental investigation of solid fuel combustion in a laminar flow reactor with high-speed laser diagnostics. The main focus lays on the development of image evaluation approaches for accurate determination of single-particle ignition based on optical measurement data. Homogeneous ignition of individual bituminous coal part...
Article
Full-text available
The synthetic Diesel fuel oxymethylene ether (OME) is sulfur-free by nature, and due to the low soot formation, no active filter regeneration events are required, limiting the maximum temperatures seen by the exhaust catalysts to ~ 450 °C. These OME-specific ageing requirements will enable the application of new types of catalysts that cannot be us...
Article
The assessment of the efficacy and mode of action of flame retardants in polymers requires a thorough knowledge of the coupling of the presence of chemical inhibitors with the underlying heat and mass transport processes. In this experimental work, we combine a thermal decomposition analysis with optical combustion diagnostics in different test env...
Preprint
Full-text available
Storing electrical energy for long periods and transporting it over long distances is an essential task of the necessary transition to a CO$_2$-free energy economy. An oxidation-reduction cycle based on iron and its oxides represents a very promising technology in this regard. The present work assesses the potential of converting an existing modern...
Article
Full-text available
The performance of a wavelet-based optical flow velocimetry (wOFV) algorithm in extracting high accuracy and high-resolution velocity fields from tracer particle images in wall-bounded turbulent flows is assessed. wOFV is first evaluated using synthetic particle images generated from a channel flow DNS of a turbulent boundary layer. The sensitivity...
Preprint
Full-text available
A combined experimental and numerical investigation of partially premixed laminar methane-air flames undergoing side-wall quenching (SWQ) is performed. A well-established SWQ burner is adapted to allow the seeding of the main flow with additional gaseous products issued from a (secondary) wall inlet close to the flame's quenching point. First, the...
Article
Full-text available
Fundamental studies on the effects of differential diffusion of hydrogen (H2) on flame structure are motivated as the high diffusivity of H2 presents challenges for the modeling and optimization of combustion systems. Polyhedral Bunsen flames are examples of cellular flames mainly induced by the thermal-diffusive and hydrodynamic instabilities, whi...
Article
Full-text available
High-temperature oxidation of single iron particles is experimentally investigated for laminar flow conditions using multi-parameter optical diagnostics. Iron particles with initially porous structures are studied with average diameters of 28 µm (A) and 87 µm (B). Simultaneous diffuse backlight-illumination (DBI) and luminosity imaging (LU) measure...
Article
In the present study, reduced kinetics considering both differential diffusion effects and strong heat losses, based on the Reaction–Diffusion Manifold (REDIM) method, formulated and constructed in generalized coordi-nates, is proposed. The approach fully coupled to a CFD solver is applied to the side-wall quenching (SWQ) of a laminar premixed dime...
Article
In premixed flame propagation of lean hydrogen or hydrogen-enriched blends, both hydrodynamic and thermo-diffusive instabilities are governing the flame front shape and affect its propagation velocity. As a result, different types of cellular patterns can occur along the flame front in a laminar scenario. In this context, an interesting phenomenon...
Article
Hydrogen is a carbon-free energy carrier that can substantially support the decarbonization of the power generation and transportation sector in the near future. Blending H2 into natural gas represents a feasible option to continue using the current infrastructure, allowing a smooth transition to pure H2 combustion technologies. In the present stud...
Article
Chemical energy vectors will play a crucial role in the transition of the global energy system, due to their essential advantages in storing energy in form of gaseous, liquid, or solid fuels. Ammonia (NH3) has been identified as a highly promising candidate, as it is carbon-free, can be stored at moderate pressures, and already has a developed dist...
Article
Velocities and flame front locations are measured simultaneously in a turbulent, side-wall quenching (SWQ) V-shaped flame during flame-wall interaction (FWI) at 1 and 3 bar by means of particle image velocimetry (PIV) and planar laser-induced fluorescence of the OH radical (OH-PLIF). The turbulent flame brush is characterized based on the spatial d...
Article
The combustion of renewable fuels such as methanol or ethanol produces comparatively large concentrations of formaldehyde (CH2O) as a combustion intermediate. This intermediate needs to be quantitatively measured using non-intrusive laser diagnostics to provide a better understanding of the chemical processes in the reaction zone. Spontaneous Raman...
Article
Turbulent mixing processes and species transport govern many important properties like stability and pollutant formation of reactive systems. We propose spectrally resolved absorption tomography as a viable tool to quantitatively assess species transport by imaging tracer pulses at high time resolution. Measurements on a gas-assisted solid-fuel com...
Article
The interaction of coal particles and recycled/recirculated flue gas (RFG) with elevated temperatures and low levels of oxygen occurs in various pulverised coal combustion scenarios. In this work, the effect of oxygen level and temperature on single coal particle combustion characteristics and NO x formation in N 2 diluent is studied by means of fu...
Article
The introduction of fibrous aspherical biomasses for the substitution of coal as a sustainable solid fuel causes complex particle-turbulence interactions, which need to be captured using minimally invasive laser-based diagnostics. High-resolution two-phase particle image velocimetry (PIV) of high-velocity biomass-laden turbulent flows require laser...
Article
A combined experimental and numerical investigation of partially premixed laminar methane-air flames undergoing side-wall quenching (SWQ) is performed. A well-established SWQ burner is adapted to allow the seeding of the main flow with additional gaseous products issued from a (secondary) wall inlet close to the flame’s quenching point. First, the...
Article
The importance of near-wall processes in internal combustion engines, such as near-wall heat transfer, will increase with the current trend toward engine downsizing. Engine boundary layers have been shown to differ from canonical steady-state turbulent boundary layers. A comprehensive understanding of the structure and behaviour of engine boundary...
Chapter
Full-text available
A fundamental understanding of droplet dynamics is important for the prediction and optimization of technical systems involving drops and sprays. The Collaborative Research Center (CRC) SFB-TRR 75 was established in January 2010 to focus on the dynamics of basic drop processes, and in particular on processes involving extreme ambient conditions, fo...
Chapter
Full-text available
Physics of supercritical fluids is extremely complex and not yet fully understood. The importance of the presented investigations into the physics of supercritical fluids is twofold. First, the presented approach links the microscopic dynamics and macroscopic thermodynamics of supercritical fluids. Second, free falling droplets in a near to supercr...
Article
Full-text available
The present work reports an experimental study of particle group combustion of pulverized bituminous coal in laminar flow conditions using advanced multi-parameter optical diagnostics. Simultaneously conducted high-speed scanning OH-LIF, diffuse backlight-illumination (DBI), and Mie scattering measurements enable analyses of three-dimensional volat...
Article
Full-text available
A combined numerical and experimental investigation is carried out to analyze the cycle-to-cycle variations (CCV) in an optically accessible spark-ignition engine with port fuel injection. A stable and an unstable operating condition is considered. Well-established turbulence, combustion, and ignition models are employed in the large-eddy simulatio...
Article
Full-text available
Cyclic variability is investigated in an optically accessible single-cylinder spark-ignition research engine by introducing artificial exhaust gas in controlled amounts to the homogenous air–fuel mixture before ignition. A skip-fire scheme ensures the absence of internal exhaust gas recirculation (EGR) and allows the engine to be fired continuously...
Article
Full-text available
Motion and swelling behavior of single bituminous coal particles during volatile combustion are investigated in a laminar flow reactor using a joint experimental and numerical approach. Three different particle samples with mean diameters of 90, 120, and 160 µm are studied in a conventional N2/O2 atmosphere with 20 vol% O2 mole fraction. Diffuse ba...
Conference Paper
Full-text available
A novel single-cavity laser system with flexible pulsing schemes suitable for particle image velocimetry (PIV) measurements is presented. The system is based on the concept of picking selected pulse pairs from an ultra-high repetition rate fiber laser which enables time-resolved and conventional dual-pulse PIV at highly flexible recording frame rat...
Conference Paper
The development of combustion processes to achieve higher efficiencies has led to a continuous increase in operating pressures that exceed the critical point of the injected fluids. Especially for supercritical atmospheric conditions with respect to the injected fluid, the fundamental physics of the occurring mixing and evaporation processes are no...
Article
Full-text available
A novel single-cavity laser system with flexible pulsing schemes suitable for particle image velocimetry (PIV) measurements is presented. The system is based on the concept of picking selected pulse pairs from an ultra-high repetition rate fiber laser which enables time-resolved and conventional dual-pulse PIV at highly flexible recording frame rat...
Article
The performance of a wavelet-based optical flow velocimetry (wOFV) algorithm in extracting high accuracy and high resolution velocity fields from tracer particle images in wall-bounded flows is as sessed. wOFV is first evaluated using a DNS database of a turbulent boundary layer, which served as ground truth synthetic data. The sensitivity of wOFV...
Article
A novel, pressurized side-wall quenching (SWQ) burner test rig enabling investigations on flame-wall interactions (FWI) of a fully premixed V-shaped flame at conditions mimicking some characteristics of practical devices, e.g. increased pressures and Reynolds numbers, is introduced within this study. Two operating cases featuring turbulent flow con...
Article
Full-text available
The application of a compact pulsed fiber laser for high-speed time-resolved particle image velocimetry (TR-PIV) measurements in the potential core of a turbulent round jet is presented at repetition rates of up to $$500\,\hbox {kHz}$$ 500 kHz . The master oscillator power amplifier laser architecture consists of a pulsable seed diode whose emissio...
Conference Paper
The feasibility of a recently developed eddy-resolving model of turbulence, termed as Very LES (Large-Eddy-Simulation), was tested by simulating the flow dynamics in two moving piston-cylinder assemblies. The first configuration deals with the compression of a tumbling vortex generated during the intake process within a cylinder with the square cro...
Conference Paper
The feasibility of a recently developed eddy-resolving model of turbulence, termed as Very LES (Large-Eddy-Simulation), was tested by simulating the flow dynamics in two moving piston-cylinder assemblies. The first configuration deals with the compression of a tumbling vortex generated during the intake process within a cylinder with the square cro...
Article
A single-cylinder full-metal engine with a real combustion chamber geometry was used to investigate particulate number emissions resulting from transient engine operation. The formation of particulate number emissions depends on mixture formation influenced by the in-cylinder flow and injection, and the formation of fuel films on the in-cylinder wa...
Article
Chemical energy carriers synthesized from renewable energy sources such as ethanol or oxymethylene ethers (OME) will become increasingly important for CO2-neutral thermochemical energy conversion processes. Therefore, it is important to make these processes efficient and clean. This needs more predictive numerical simulation tools and an improved u...
Article
Full-text available
Oxy-fuel combustion is a promising strategy to minimize the environmental impact of combustion-based energy conversion. Simple and flexible tools are required to facilitate the successful integration of such strategies at the industrial level. This study couples measured residence time distribution with chemical reactor network analysis in a close-...