Early flame propagation of hydrogen enriched methane-air mixtures at quasi laminar conditions in a rapid compression expansion machine

Kammermann, Thomas; Giannakopoulos, George; Koch, Jann; Soltic, Patrik; Boulouchos, Konstantinos

doi:10.1016/j.ijhydene.2019.08.155

Cited by 7 publications

(2 citation statements)

References 38 publications

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“…High energy densities and temperature gradients in the transition between plasma expansion and flame formation are achieved if spark discharge is accomplished in the shortest possible time interval [3]. Ultrafast highly powerful discharges should lead to a fast and repeatable transition from ignition to the early flame kernel to turbulent flame propagation [5]. With nanosecond pulsed discharge, the energy input is applied mainly during the breakdown phase, where hightemperature gradients should lead to high flame speeds [6].…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Breakdown With Nanosecond Pulses for Spark-Ignition Engines

et al. 2021

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The influence of pulse rise rate and pulse duration for ignition purposes in engines is investigated. A constant volume cell is used to characterize the breakdown voltage under nanosecond pulsed voltages with automotive sparkplugs having electrode gaps ranging from 0.2 mm to 1 mm. Two pulse generators are used to compare pulses with durations of 10 ns and 50 ns. Different pulse amplitudes are used, and air gaps with breakdown voltages ranging from 4 kV to 15 kV are investigated. The cell is filled with synthetic air with densities gap distances products that are relevant for internal combustion engines. This study shows that the pulse shape and rise rate influence the breakdown voltage. Under pulsed discharge, the breakdown voltage is always above the static breakdown voltage. The probability of pulsed discharge breakdown increases as both the pulse amplitude and duration increases. Furthermore, the breakdown voltage value increases with increasing pulse rise rate. The delay time between reaching the static breakdown voltage and the actual breakdown voltage decreases with increasing overvoltage. The delay time is constituted by statistical and formative times. Both the statistical and formative times decrease with increasing overvoltage. For ignition purposes, the pulse rise rate should be as high as possible to deliver a larger energy input in the breakdown phase. Furthermore, for reduced electrode erosion, the pulse duration should be short (10-20 ns) to reduce the probability for a transition to an arc.

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Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Breakdown With Nanosecond Pulses for Spark-Ignition Engines

et al. 2021

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“…RCEMs (rapid compression and expansion machines) can be positioned somewhere between constant volume cells and optical single cylinder engines. They provide a single compression and expansion stroke comparable to real engines and have therefore no difficulties to work in premixed [19][20][21] or dual fuel combustion modes [22,23]. The filling and emptying process of the cylinder volume is decoupled from the fast compression and expansion, respectively; thus, no large intake and exhaust valves are required that limit the optical access.…”

Section: Introductionmentioning

confidence: 99%

The Flex-OeCoS—a Novel Optically Accessible Test Rig for the Investigation of Advanced Combustion Processes under Engine-Like Conditions

et al. 2020

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A new test rig has been designed, built and commissioned, and is now jointly pursued to facilitate experimental investigations into advanced combustion processes (i.e., dual fuel, multi-mode) under turbulent conditions at high, engine-like temperature and pressure levels. Based on a standard diesel engine block, it offers much improved optical access to the in-cylinder processes due to its separated and rotated arrangement of the compression volume and combustion chamber, respectively. A fully variable pneumatic valve train and the appropriate preconditioning of the intake air allows it to represent a wide range of engine-like in-cylinder conditions regarding pressures, temperatures and turbulence levels. The modular design of the test rig facilitates easy optimizations of the combustion chamber/cylinder head design regarding different experimental requirements. The name of the new test rig, Flex-OeCoS, denotes its Flexibility regarding Optical engine Combustion diagnostics and/or the development of corresponding Sensing devices and applications. Measurements regarding in-cylinder gas pressures, temperatures and the flow field under typical operating conditions are presented to complete the description and assessment of the new test rig.

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Effects of hydrogen-enriched methane combustion on latent heat recovery potential and environmental impact of condensing boilers

Bălănescu

Homutescu

2021

Applied Thermal Engineering

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Early flame propagation of hydrogen enriched methane-air mixtures at quasi laminar conditions in a rapid compression expansion machine

Cited by 7 publications

References 38 publications

Experimental Analysis of Breakdown With Nanosecond Pulses for Spark-Ignition Engines

Experimental Analysis of Breakdown With Nanosecond Pulses for Spark-Ignition Engines

The Flex-OeCoS—a Novel Optically Accessible Test Rig for the Investigation of Advanced Combustion Processes under Engine-Like Conditions

Effects of hydrogen-enriched methane combustion on latent heat recovery potential and environmental impact of condensing boilers

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