Andreas Dreizler

Andreas Dreizler
Technische Universität Darmstadt | TU · Department of Mechanical Engineering (Dept.16)

Prof. Dr. habil.

About

380
Publications
36,580
Reads
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8,098
Citations
Citations since 2016
168 Research Items
4989 Citations
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201620172018201920202021202202004006008001,000
201620172018201920202021202202004006008001,000
201620172018201920202021202202004006008001,000

Publications

Publications (380)
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
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
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
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...
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-...
Article
In this study the characteristics of multi-regime combustion are investigated using a multi-regime burner with well-defined inflow boundary conditions. Based on previous findings, the range of operating conditions is extended. Fluid dynamical and thermochemical states are analysed for a variety of fuel/air ratios. Based on comprehensive Raman/Rayle...
Article
Fundamental studies on Flame-Wall Interaction (FWI) are of the utmost importance to unravel the intricate coupling between chemistry and transport in the near-wall region, and to characterize the quenching dynamics. For this purpose, an accurate description of reaction kinetics is especially needed. In this work, the role of chemistry during the wa...
Article
Spatially and temporally resolved information on thermochemical conditions in hydrocarbon/air flames requires concentration and temperature data obtained by spontaneous Raman/Rayleigh scattering. During the combustion of renewable and more complex fuels, such as ethanol, partially oxidized hydrocarbons are created as intermediates in concentrations...
Article
This study focuses on exploring the thermochemistry in flame-wall interaction (FWI) for fully premixed side-wall quenching of a laminar, atmospheric-pressure dimethyl ether flame at equivalence ratio Φ=0.83 by simultaneous measurement of CO2 and CO mole fractions and gas phase temperature T. The applied laser diagnostics are dual-pump coherent anti...
Article
Large-eddy simulations are conducted for Darmstadt turbulent methane-hydrogen flames (MHFs, 20%H2+80%CH4 in volume fraction). Two different flames are investigated: one without stratification at the fuel inlets (MHF5) and the other with stratification (MHF7). Two different flamelet libraries are generated: one based on the unity Lewis number assump...
Article
Thermochemical states of a turbulent, lean premixed dimethyl ether/air flame were assessed for the first time using simultaneous measurements of gas temperature T, CO2 and CO mole fractions with locations as close as 120 μm above the quenching wall. This is realized by combined dual-pump coherent anti-Stokes Raman spectroscopy (DP-CARS) and two-pho...
Article
Full-text available
In this work, an experimental investigation of AdBlue film formation in a generic selective catalytic reduction (SCR) exhaust gas test bench is presented. AdBlue is injected into a generic SCR test bench resulting in liquid film formation on the lower wall of the channel. The thickness of this liquid film is measured using a film thickness sensor b...
Article
Full-text available
Predictions made by climate researchers are highly worrisome and demand rapid action to avoid the threat of climate catastrophe. Global energy systems must be transformed as quickly as possible by minimising or avoiding net greenhouse gas emissions. There is broad agreement on this goal, demonstrated by international treaties such as the Sustainabl...
Article
Transient engine operation of direct-injection spark ignition engines can result in high particulate number emissions. To investigate the causes of soot formation, an engine test rig was developed to perform detailed measurements of real transient operation. For this purpose, a single-cylinder full-metal engine with a real combustion chamber geomet...
Article
Full-text available
The ignition and volatile combustion of single coal particles were investigated under laminar conditions. Relevant physico-chemical processes were analyzed under conventional and oxy-fuel atmospheres with varying O2 contents in experiments and simulations. An optically accessible laminar flow reactor with well-defined boundary conditions measured w...
Article
This article reviews the challenge of expanding the current research focus on water and CO2 electrolysis from catalyst-related insights towards achieving complete understanding of the activity transport nexus within full electrolysis cells. The challenge arises from the complex interaction of a multitude of phenomena taking place at different scale...
Chapter
This study combines advanced optical diagnostics and high-fidelity Direct Numerical Simulations (DNS) to deepen the understanding of wall heat transfer processes in Otto engines under motored and fired conditions. To this end, a combination of optical diagnostics was applied simultaneously: High-resolution Particle Image Velocimetry (PIV) and Parti...
Conference Paper
Full-text available
Oxy-fuel combustion is a promising strategy to minimize the environmental impact of combustion-based energy generation. 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 reactors network analysis in a close...
Poster
Full-text available
Oxy-fuel combustion minimizes 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. Chemical Reactor Network (CRN) modelling guided by Residence Time Distribution (RTD) measurements enables the understanding of the d...
Article
Wall and gas phase temperatures inside a swirled oxy-fuel combustion chamber are important to characterize the combustion process. Wall temperatures were measured by thermographic phosphors and discussed in combination with gas phase temperatures. For gas phase temperatures an O2 vibrational coherent anti-Stokes Raman scattering (CARS) approach was...
Article
Thermochemical interaction – represented by CO mole fraction and gas phase temperature measurements – between flame and cooling air is investigated in a close-to-reality effusion-cooled single sector model gas turbine combustor. To investigate the influence of effusion cooling air mass flow on the thermochemical state, a parametric study is conduct...
Article
Full-text available
Mixing processes between main flow and effusion cooling air are investigated in an effusion cooled, swirl-stabilized pressurized single sector gas turbine combustor using advanced laser diagnostics. Quantitative planar laser-induced fluorescence of the hydroxyl radical (OH-PLIF) and planar laser-induced fluorescence of nitric oxide, seeded to the e...
Article
Oxy-fuel combustion promises efficient and inexpensive carbon dioxide sequestration and is therefore subject to active experimental research. However, the transfer of mature, non-intrusive diagnostic methods for temperature measurement like Coherent Anti-Stokes Raman Spectroscopy (CARS) from air-fed to oxy-fuel systems is challenging due to the def...
Article
Full-text available
The COVID-19 pandemic caused tremendous supply bottlenecks of single-use filtering facepiece respirators (FFRs) leading to a growing need for a potential reuse. This study assesses the impact of multiple mild-steam decontaminations with 121 °C/2000 mbar/20 min on the protection performance of disposable FFRs. It focuses on FFRs of type KN95 that is...
Article
Full-text available
The local heat-release rate and the thermo-chemical state of laminar methane and dimethyl ether flames in a side-wall quenching configuration are analyzed. Both, detailed chemistry simulations and reduced chemistry manifolds, namely Flamelet-Generated Manifolds (FGM), Quenching Flamelet-generated Manifolds (QFM) and Reaction-Diffusion Manifolds (RE...
Article
Full-text available
Near-wall processes in internal combustion engines strongly affect heat transfer and pollutant emissions. With continuously improving capabilities to model near-wall processes, the demand for corresponding measurements increases. To obtain an in-depth understanding of the near-wall processes within spark-ignition engines, flame distributions and fl...
Article
Full-text available
To study combustion fundamentals of complex fuels under well-defined boundary conditions, a novel Temperature Controlled Jet Burner (TCJB) system is designed that can stabilise both gaseous or pre-vaporised liquid fuels. In a first experimental exploratory study, piloted turbulent jet flames of pre-vaporised methanol, ethanol, 2-propanol and 2-buta...
Article
Full-text available
The numerical investigation of quenching distances in laminar flows is mainly concerned with two setups: head-on quenching (HOQ) and side-wall quenching (SWQ). While most of the numerical work has been conducted for HOQ with good agreement between simulation and experiment, far less analysis has been done for SWQ. Most of the SWQ simulations used s...
Article
Full-text available
Ignition and combustion of pulverized solid fuel is investigated in a laminar burner. The two-dimensional OH radical field is measured in the experiments, providing information on the first onset of ignition and a detailed characterization of the flame structure for the single particle. In addition, particle velocity and diameter are tracked in tim...
Article
Flow dynamics and temperatures of solid fuel particles strongly influence flame stabilization, local heat release and fuel conversion inside pulverized solid fuel combustors. To investigate these phenomena, experiments are carried out under well-controlled inflow and boundary conditions inside a gas-assisted, swirled oxy-fuel combustion chamber. Fl...
Article
Full-text available
A loss‐less compressed library scheme is presented in this publication that allows for computationally efficient fitting of coherent anti‐Stokes Raman spectra with no restriction to the number of degrees of freedom for the spectral fit. The compression is achieved by convolving the squared modulus and the real part of the complex susceptibility wit...
Article
Full-text available
Mixing and evaporation processes play an important role in fluid injection and disintegration. Laser-induced thermal acoustics (LITA) also known as laser-induced grating spectroscopy (LIGS) is a promising four-wave mixing technique capable to acquire speed of sound and transport properties of fluids. Since the signal intensity scales with pressure,...
Article
Machine learning (ML) models based on a large data set of in-cylinder flow fields of an IC engine obtained by high-speed particle image velocimetry allow the identification of relevant flow structures underlying cycle-to-cycle variations of engine performance. To this end, deep feature learning is employed to train ML models that predict cycles of...
Article
We present a tomographic spectrometer for the measurement of gas phase species parameter distributions within the cross section of a generic exhaust gas test rig built for the investigation of the physico-chemical processes during exhaust gas aftertreatment with selective catalytic reduction (SCR). A urea-water solution (UWS) is injected into the h...
Article
This paper investigates a self-sustained swirl-stabilized pulverized coal combustion chamber, specially designed to validate numerical models under atmospheric and oxy-fuel conditions. For this purpose, a comprehensive model, which accounts for both atmospheric and oxy-fuel conditions, is developed based on Large Eddy Simulation. To describe the tu...
Article
Full-text available
The volatile combustion of Colombian high-volatile bituminous coal was experimentally studied in a laboratory laminar flow reactor. The volatile flames corresponding to the single particle and particle group combustion were visualized using non-intrusive multi-parameter optical diagnostics. In the present study, high-speed laser-induced fluorescenc...
Article
Full-text available
High-speed, three-dimensional (3D) scalar-velocity field measurements are demonstrated in a lifted partially-premixed dimethyl-ether/air jet flame using simultaneous laser-induced fluorescence (LIF) of formaldehyde (CH 2 O) and tomographic particle image velocimetry (TPIV). The 3D LIF measurements are performed by raster scanning the laser beam fro...
Article
Full-text available
The transition from single to group high-volatile bituminous (hvb) coal particle combustion is experimentally investigated in a laminar flow reactor using state-of-the-art laser diagnostics. Simultaneous volumetric OH-LIF imaging using a novel laser scanning technique is combined with time-resolved diffuse backlight-illumination (DBI) providing fun...
Article
The numerical investigation of quenching distances in laminar flows is mainly concerned with two setups: head-on quenching (HOQ) and side-wall quenching (SWQ). While most of the numerical work has been conducted for HOQ with good agreement between simulation and experiment, far less analysis has been done for SWQ. Most of the SWQ simulations used s...
Preprint
Full-text available
Resolving fluid transport at engine surfaces is required to predict transient heat loss, which is becoming increasingly important for the development of high-efficiency internal combustion engines (ICE). The limited number of available investigations have focused on non-reacting flows near engine surfaces, while this work focuses on the near-wall f...
Preprint
Full-text available
Fuel sprays produce high-velocity, jet-like flows that impart turbulence onto the ambient flow field. The spray-induced turbulence augments fuel-air mixing, which has a primary role in controlling pollutant formation and cyclic variability in engines. This paper presents tomographic particle image velocimetry (TPIV) measurements to analyse the 3D s...
Preprint
Full-text available
Understanding the detailed flame transport in IC engines is important to predict ignition, rate of heat release and assess engine performance. This is particularly important for RANS and LES engine simulations, which often struggle to accurately predict flame propagation and heat release without first adjusting model parameters. Detailed measuremen...
Article
In this work, the flame structures of the recent Darmstadt turbulent premixed/stratified flame series with 20% volume fraction H2 addition (Schneider et al., PCI, 2019) are analyzed using flamelet tabulated manifolds. Three different methane/hydrogen flames (MHFs) with increasing complexity are studied. The effects of differential diffusion, stretc...
Article
Recent investigations on a novel multi-regime burner (MRB) configuration showed significant deviations in the CO flame structure compared to the limiting cases of premixed and non-premixed flames. However, a prior analysis revealed that major species and temperature are captured by both limiting cases (Butz et al., Combust. Flame, 2019 [1]). In the...
Article
Mean temperatures of acetone, millimeter-sized, freely falling droplets in a nitrogen atmosphere are studied at two different locations downstream a capillary-type injector. Injection and ambient temperatures have been varied independently between 433 and 513 K and pressures from 2 to 6 MPa. The ratio of simultaneously measured laser-induced phosph...
Article
High-speed Mie scatter imaging and in-cylinder pressure measurements are performed in an optically accessible four-stroke spark-ignition engine to investigate cycle-to-cycle variations (CCVs). Droplet Mie scattering is used to measure the cross-sectional flame contour. Machine learning (ML) methods are applied to predict combustion cycles of high m...
Article
Full-text available
Records of the time-varying temperature profile at flight relevant operating conditions are acquired at the exit of a combustion chamber fitted with a staged, lean-burn fuel injector using high-speed laser induced fluorescence (LIF) at a sample rate of 10 kHz. Temperatures are estimated from the concentration dependent fluorescence of the hydroxyl...
Technical Report
Full-text available
Die Vorhersagen der Klimaforschung sind hochgradig besorgniserregend. Gleichzeitig spornen sie zu raschem Handeln an. Um die drohende Klimakatastrophe zu vermeiden, muss das globale Energiesystem schnellstmöglich so umgestaltet werden, dass nahezu keine Treibhausgase mehr in die Atmosphäre entweichen. In diesem Ziel ist man sich weitgehend einig. D...
Article
This paper analyses a new gas-assisted pulverized coal combustion chamber, specially designed for the validation of numerical models under oxy-fuel atmospheres. For this purpose, an overall method is developed based on Large Eddy Simulation (LES) for oxy-fuel pulverized coal combustion chambers. One essential aspect of this is the embedding of a 4D...
Article
Coal combustion is strongly influenced by the interaction of gas phase turbulence, particle dynamics and chemistry. To advance the understanding of these mutually coupled processes, experiments under well-controlled inflow and boundary conditions are needed that provide access to non-intrusive multi-parameter measurement techniques. Following this...
Conference Paper
Particle image velocimetry measurements of the in-cylinder flow in an optically accessible single-cylinder research engine were taken to better understand the effects of intake pressure variations on the flow field. At a speed of 1500 rpm, the engine was run at six different intake pressure loads from 0.4 to 0.95 bar under motored operation. The av...