Optical investigation on polyoxymethylene dimethyl ethers spray flame at different oxygen levels in a constant volume vessel

Zheng, Zunqing; Liu, Wei; Liu, Haifeng; Feng, Lei; Cui, Yanqing; Zhang, Shuo; Yao, Mingfa

doi:10.1007/s11431-020-1764-y

Cited by 11 publications

(6 citation statements)

References 55 publications

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“…POMDME optical investigations. POMDME as a sole replacement for compression ignition is optically investigated in constant volume chambers, 46,50,54,[59][60][61][62][63][64] rapid compression expansion machines, optically accessible engines 42,51,65,66 and as blends. 45,51,67 Macroscopically, the spray of OME 3-5 offered a high lift-off length despite a short ignition delay in a constant volume high-pressure chamber, indicative of a favorable mixing behavior with relatively high air-fuelratio -positively affected by the inherent oxygen content -in the fuel-rich zone near the injector.…”

Section: Pilot-ignited Lean-premixed Natural Gas Enginesmentioning

confidence: 99%

“…76 Another study substantiated the findings and connected the oxidation of CO and unburned hydrocarbons with its blue chemiluminescence as the primary contributor to OME flame luminescence. 63 CO oxidation is present in a spectral band peaking around 450 nm. 77 The observed flame tip at the cones emitted high-temperature thermal radiation from combustion products.…”

Section: Pilot-ignited Lean-premixed Natural Gas Enginesmentioning

confidence: 99%

“…POMDME as a sole replacement for compression ignition is optically investigated in constant volume chambers, 46,50,54,59–64 rapid compression expansion machines, optically accessible engines 42,51,65,66 and as blends. 45,51,67…”

Section: Introductionmentioning

confidence: 99%

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Optical study on a heavy-duty natural gas dual-fuel engine applying POMDME as pilot fuel

Mühlthaler,

Prager,

Jaensch

2024

International Journal of Engine Research

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In this study, a fully optically accessible single-cylinder research engine is the basis for the visualization and generation of extensive knowledge about the in-cylinder processes of mixture formation, ignition, and combustion of alternative fuels for the dual-fuel combustion process. POMDME substitutes the fossil pilot fuel as a drop-in, non-sooting alternative to widely eliminate the NOx-PM tradeoff. Furthermore, an optimized ignition behavior, increased degrees of freedom in combustion phasing, and the pilot’s energy content are expected. The flame luminosity transmitted via an optical piston was split in the optical path to record the natural flame luminosity simultaneously with an RGB high-speed camera. The second channel consisted of OH chemiluminescence recording, isolated by a bandpass filter via an intensified monochrome high-speed camera. To investigate the combustion process spectrally, spatially, and temporally resolved in more detail, selected operating points were re-recorded via a high-speed imaging spectrograph. POMDME is benchmarked against regular diesel oil, according to EN590. Synthetic natural gas is applied as the primary gaseous fuel. Experimental sweeps along the overall pilot’s energy content (2%, 5%, 10%), injection pressure (500–1600 bar), and start of energizing (5–55 CAD bFTDC) are carried out. The given conditions result in decreased liquid-penetration length between 25% and 30% for the oxygenate, larger for earlier SOE and higher dilution. The lift-off length is nearer the liquid penetration length, increasing for higher rail pressures. The light-based ignition delay for EN590 is enlarged by 0.8 CAD after adding methane, while the oxygenate is not visibly retarded. Without methane, the oxygenate preceded EN590 by 0.6 CAD. The temporal and spatial position and extent of premixed, diffusive, and OH*, change significantly. RCCI operation at practically relevant 18.4 bar IMEP is demonstrated, highlighting the influence of the start of energizing variation with 51% decreased burn duration in the first half of combustion.

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Section: Pilot-ignited Lean-premixed Natural Gas Enginesmentioning

confidence: 99%

Section: Pilot-ignited Lean-premixed Natural Gas Enginesmentioning

confidence: 99%

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Optical study on a heavy-duty natural gas dual-fuel engine applying POMDME as pilot fuel

Mühlthaler,

Prager,

Jaensch

2024

International Journal of Engine Research

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“…It has been found that with the rising of oxygen level, the ignition delay was shortened, the luminosity intensity in the flame core increased and the shape of the spray flame was shortened and narrowed. In addition to the reason that higher oxygen concentration allowed more fuels to reach the appropriate equivalent ratio more quickly, chemical kinetics also played an important role, which can be proved by the study on oxygen-containing fuel polyoxymethylene dimethyl ethers (PODE) by Zheng et al [13]. They conducted optical investigation on PODE spray flame at different oxygen levels in a constant volume vessel and obtained similar conclusions in the ignition delay, the luminosity intensity in the flame core and the shape of the spray flame.…”

Section: The Chemical Reaction Path Analysismentioning

confidence: 99%

“…Some studies have shown that there are significant differences in the combustion process, NOx, CO, soot and other typical species under oxygen-enriched conditions and air conditions. Zheng et al [13] studied polyoxymethylene dimethyl ethers spray flame at different oxygen levels in a constant volume vessel. Results showed that as the oxygen concentration increases, the flame natural luminosity and propagation speed increased, the position of lift-off region and flame tip moved towards the injector nozzle, and the flame width became narrower.…”

Section: Introductionmentioning

confidence: 99%

Experimental and kinetic modeling studies on oxidation of n-heptane under oxygen enrichment in a jet-stirred reactor

et al. 2022

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Oxygen-enriched combustion can improve thermal efficiency and reduce CO, unburned hydrocarbons and soot emissions in internal combustion engines. There are significant differences in the combustion process and pollutant emissions between oxygen-enriched and air condition. In order to develop an improved understanding of the effect of oxygen concentration on n-heptane oxidation, the jet-stirred reactor oxidation characteristics of n-heptane were experimentally tested at temperatures of 450-950 K and pressures of 1.03 atm with the residence time (τ) of 2 s, under the condition of oxygen mole fractions from 0.055 to 0.6. Meantime, the simulations were performed on CHEMKIN. Results show that, firstly, with the increase of oxygen concentration, the NTC (Negative Temperature Coefficient) effect is weakened, mainly due to the strengthening of low-temperature reaction path, which is also the reason for the improvement of ignition stability in cold-start condition of engines. Secondly, the activity of the reaction system improves with the increase of oxygen concentration. Within 500-750 K, it is due to enhancement of the low-temperature reaction path. When the temperature is higher than 750 K, the improvement is due to the enhancement of decomposition of H2O2 and addition reaction of H and O2. Thirdly, with the increase of oxygen concentration, both the generation and consumption of CO are strengthened, which leads to the tip of the diesel spray flame changing from soot area under air condition to the CO chemiluminescence.

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Measurements and Derivation of the Spray Simulation Required Physical Properties of Polyoxymethylene Dimethyl Ethers (PODEn)

2023

Int J Thermophys

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Optical investigation on polyoxymethylene dimethyl ethers spray flame at different oxygen levels in a constant volume vessel

Cited by 11 publications

References 55 publications

Optical study on a heavy-duty natural gas dual-fuel engine applying POMDME as pilot fuel

Optical study on a heavy-duty natural gas dual-fuel engine applying POMDME as pilot fuel

Experimental and kinetic modeling studies on oxidation of n-heptane under oxygen enrichment in a jet-stirred reactor

Measurements and Derivation of the Spray Simulation Required Physical Properties of Polyoxymethylene Dimethyl Ethers (PODEn)

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