Exergy losses in premixed flames of dimethyl ether and hydrogen blends

Zhao, Tianfeng; Zhang, Jiabo; Ju, Dehao; Huang, Zhen; Han, Dong

doi:10.1007/s11708-019-0645-8

Cited by 8 publications

(3 citation statements)

References 46 publications

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“…Several studies have suggested that blending hydrogen with carbon oxides (i.e., methane or DME, etc.) as the fuel can reduce the emission of carbon oxides, exergy losses, and the likelihood of blow-off [12][13][14][15]. This is because hydrogen addition enhances the combustion intensity of the CH 4 /air flame.…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of the Effect of Hydrogen Ratio on the Flame Stabilization and Blow-Off Dynamics of a Lean CH4/H2/Air Bluff-Body Flame

Cheng,

Zhang,

Peng

et al. 2024

Applied Sciences

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This study investigated the flame structure and dynamics of a bluff-body flame when numerically close to blow-off conditions. This includes the impact of the hydrogen ratio on lean CH4/H2/air flame stabilization and blow-off characteristics. In this study, we assessed the impacts of four different hydrogen ratios: 0%, 30%, 60%, and 90%. Large eddy simulation (LES) was coupled with a thickened flame (TF) model to determine the turbulent combustion using a 30-species skeletal mechanism. The numerical results were progressively validated using OH-PLIF and PIV techniques. The results obtained from the numerical simulations showed minor differences with the experimental data on the velocity field and flame structure for all conditions. The presented results reveal that the flame is stabilized in higher-strain-rate spots more easily in the presence of high hydrogen ratios. Moreover, the flame location moves away from the concentrated vortex area with an increasing hydrogen ratio. The results of our blow-off investigation indicate that the blow-off sequence of a premixed bluff-body flame can be separated into two stages. The entire blow-off process becomes shorter with an increase in the hydrogen ratio. The primary reason for global extinction is a reduction in the heat release rate, and enstrophy analysis implies that blending hydrogen can reduce the enstrophy values of flames at the downstream locations. The dilatation and baroclinic torque terms decrease close to blow-off, but their decline is not significant in high-hydrogen-ratio conditions.

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Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of the Effect of Hydrogen Ratio on the Flame Stabilization and Blow-Off Dynamics of a Lean CH4/H2/Air Bluff-Body Flame

Cheng,

Zhang,

Peng

et al. 2024

Applied Sciences

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“…The reactions with H2, H, and H2O as reactants were inhibited, decreasing the loss from chemical reaction. Zhao et al [22] increased H2 substitution in a DME/H2/air flame mixture and found that the addition of H2 reduced the exergy losses from chemical reactions and heat conduction, increased the exergy losses from incomplete combustion, and overall reduced the exergy losses. In terms of energy requirement and cost, taking China as an example, the White Paper on China's Hydrogen Energy and Fuel Cell Industry states that it is predicted that the total hydrogen demand in China will reach 30 million tons by 2025 and 35 million tons by 2030 [23].…”

Section: Introductionmentioning

confidence: 99%

Effects of Hydrogen Addition on the Thermal Performance and Emissions of Biomass Syngas Combustion in a Horizontal Boiler

Suxing,

Yu,

et al. 2024

Energies

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Due to its low calorific value, abnormal phenomena such as incomplete combustion and flameout may occur during the combustion process of biomass syngas. The applicability of adding hydrogen can assist in the combustion of biomass syngas in boilers to overcome the above defects, and the effects need to be investigated. In this study, a multi-mechanism model is employed to numerically simulate the flow and combustion of a horizontal boiler burning biomass syngas. The reliability verification of the model is conducted by comparing it with the experimental results of combustion in a domestic boiler with biomass syngas. From the views of multi-fields and synergy, the effects of hydrogen addition on the thermal performance and emissions of biomass syngas are further expounded. Two scenarios are taken into consideration: hydrogen addition at a constant fuel volume flow rate and constant heat input. The result indicates that hydrogen addition significantly affects the multi-field synergy, which is advantageous for improving the heat transfer performance and combustion efficiency of biomass syngas. However, when the hydrogen addition ratio exceeds 20% at a constant fuel volume flow rate and 25% at constant heat input, its impact may be reduced. When the hydrogen content increases, the outlet temperature of the combustion chamber decreases, and pollutant emissions are effectively controlled. The turbulent kinetic energy at the reversal section decreases, and the uniformity of the flow field improves. These results provide certain guidance for the efficient utilization of biomass syngas and the operation of boilers burning biomass syngas.

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“…This method can not only recycle the exhaust heat, but also enable the engine to be closer to the constant volume cycle, and, thus, the thermal efficiency of the engine is improved (Ji et al, 2013). In addition, dissociated methanol gas is rich in hydrogen, and mixing hydrogen with a hydrocarbon fuel for combustion can increase the flame speed (Zhao et al, 2019), and extend the lean-burn limit (Jaimes et al, 2018). Lean combustion enables the fuel to burn completely, which further increases the thermal efficiency, and may reduce the emissions of CO (Liu and Dumitrescu, 2019).…”

Section: Introductionmentioning

confidence: 99%

An Investigation of the Kinetic Modeling and Ignition Delay Time of Methanol—Syngas Fuel

et al. 2022

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The recycling of exhaust heat in internal combustion engines to dissociate the methanol, followed by its blending with methanol to produce engine fuel, is promising for improving the efficiency of engines, and reducing emissions. The kinetic model MEOHSYNGAS1.0 for the methanol–syngas fuel is proposed by reducing the detailed chemical kinetic model (Mech15.34). Shock tube experiments are conducted to measure the ignition delay time of methanol blended with dissociated methanol gas at different dissociated methanol ratios (0, 30, 50, and 100%). The model is validated by the experimental data of the present work and with data from the literature. The effects of the equivalence ratio, pressure, and dissociated methanol ratio on the ignition delay time are investigated through reaction path analysis and sensitivity analysis. When the dissociated methanol ratio does not surpass 50%, the ignition delay time increases with the increase in the dissociated methanol ratio, which is more obvious in the low temperature range, and but decreases with the increase in temperature.

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Exergy losses in premixed flames of dimethyl ether and hydrogen blends

Cited by 8 publications

References 46 publications

Large Eddy Simulation of the Effect of Hydrogen Ratio on the Flame Stabilization and Blow-Off Dynamics of a Lean CH4/H2/Air Bluff-Body Flame

Large Eddy Simulation of the Effect of Hydrogen Ratio on the Flame Stabilization and Blow-Off Dynamics of a Lean CH4/H2/Air Bluff-Body Flame

Effects of Hydrogen Addition on the Thermal Performance and Emissions of Biomass Syngas Combustion in a Horizontal Boiler

An Investigation of the Kinetic Modeling and Ignition Delay Time of Methanol—Syngas Fuel

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