Thermodynamic Analysis of SI Engine Operation on Variable Composition Biogas-Hydrogen Blends Using a Quasi-Dimensional, Multi-Zone Combustion Model

Rakopoulos, C.D.; Michos, Constantine N.; Giakoumis, Evangelos G.

doi:10.4271/2009-01-0931

Cited by 24 publications

(15 citation statements)

References 41 publications

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“…16 is the rapid increase of the unburned gas temperature just after the ignition timing, especially for the richer mixtures. This is due to the faster hydrogen combustion occurring in these cases, where the unburned mass is further compressed and heated due to the expansion of the burned gas [47].…”

Section: Investigation Of Nitric Oxide Emissionsmentioning

confidence: 99%

A combined experimental and numerical study of thermal processes, performance and nitric oxide emissions in a hydrogen-fueled spark-ignition engine

Rakopoulos

Kosmadakis

Demuynck

et al. 2011

International Journal of Hydrogen Energy

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A COMBINED EXPERIMENTAL AND NUMERICAL STUDY OF THERMAL PROCESSES, PERFORMANCE AND NITRIC OXIDE EMISSIONS IN A HYDROGEN-FUELED SPARK-IGNITION ENGINE ABSTRACTThis work concerns the study of a spark-ignition engine fueled with hydrogen, using both measured and numerical data at various conditions, focusing on the combustion efficiency, the heat transfer phenomena and heat loss to the cylinder walls, the performance, as well as the nitric oxide (NO) emissions formed, when the fuel/air and compression ratio are varied. For the investigation of the heat transfer mechanism, the local wall temperatures and heat flux rates were measured at three locations of the cylinder liner in a CFR engine. These fluxes can provide a reliable estimation of the total heat loss through the cylinder walls and of the hydrogen flame arrival at specific locations. Together with the experimental analysis, the numerical results obtained from a validated in-house CFD code were utilized for gaining a more complete view of the heat transfer mechanism and the hydrogen combustion efficiency for the various cases examined. The performance of the CFR engine is then identified, since the calculated cylinder pressures are compared with the measured ones, from which performance and heat release rates are calculated and discussed. Further, NO emission studies have been accomplished, with the calculated results not only being compared with the measured exhaust NO ones, but also further processed for conducting an in-depth investigation of the dependence of NO production on the spatial distribution of in-cylinder gas temperature. It is revealed that for lower fuel/air ratio the burned gas temperature is held at low level and the heat loss ratio is quite low. As the load increases and stoichiometric mixtures are used, the wall and in-cylinder gas temperatures increase substantially, together with the heat loss and the NO emissions, owing to the high hydrogen combustion velocity and the consequent high rate of temperature rise. The combustion efficiency is slightly increased, but the indicated efficiency is decreased due to higher heat loss.Keywords: hydrogen; spark-ignition engine; combustion efficiency; heat transfer; NO emissions.

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Section: Investigation Of Nitric Oxide Emissionsmentioning

confidence: 99%

A combined experimental and numerical study of thermal processes, performance and nitric oxide emissions in a hydrogen-fueled spark-ignition engine

Rakopoulos

Kosmadakis

Demuynck

et al. 2011

International Journal of Hydrogen Energy

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“…The flame stretch rate (K) is constituted from the additive contributions of the geometric (K g ) and turbulent (K t ) stretch rates [31] as, (A1.14)…”

Section: Appendices Appendix A1mentioning

confidence: 99%

Experimental Study on the Burning Rate of Methane and PRF95 Dual Fuels

Petrakides¹,

Gao²,

Chen³

et al. 2016

SAE Int. J. Engines

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Natural gas as an alternative fuel offers the potential of clean combustion and emits relatively low CO 2 emissions. The main constitute of natural gas is methane. Historically, the slow burning speed of methane has been a major concern for automotive applications.Literature on experimental methane-gasoline Dual Fuel (DF) studies on research engines showed that the DF strategy is improving methane combustion, leading to an enhanced initial establishment of burning speed even compared to that of gasoline. The mechanism of such an effect remains unclear.In the present study, pure methane (representing natural gas) and PRF95 (representing gasoline) were supplied to a constant volume combustion vessel to produce a DF air mixture. Methane was added to PRF95 in three different energy ratios 25%, 50% and 75%. Experiments have been conducted at equivalence ratios of 0.8, 1, 1.2, initial pressures of 2.5, 5 and 10 bar and a temperature of 373K. At stoichiometric conditions, experiments in an SI engine have been also performed.It has been found that methane and all DFs have their fastest burning rate at stoichiometric conditions whereas PRF95 at rich conditions (Φ=1.2). At lean conditions (Φ=0.8), all DFs resulted in faster combustion than PRF95, whereas methane is the slowest of all. At rich conditions, DF75 and DF50 are slower than methane. The transition mechanism between the constant volume combustion experiments and those in the engine environment resulted in a larger increase in the burning speed of methane and all DFs in comparison to that of the liquid fuel. CITATION:

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“…Also, it gives the worst underestimation 365 of the effect of pressure on u t /u l among the models considered here. It was attempted to include the effect of stretch on the local burning velocity u n by applying the stretch submodels of both Teraji et al [29] and Chung & Law [30,31] …”

Section: Fractalsmentioning

confidence: 99%

The turbulent burning velocity of methanol–air mixtures

Vancoillie

Sharpe²,

Lawes

et al. 2014

Fuel

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Methanol is a sustainable and versatile alternative fuel for spark-ignition engines and other combustion applications. To characterize the combustion behavior of this fuel, a good understanding of the factors affecting its turbulent burning velocity is re-10 quired. This paper presents experimental values of the turbulent burning velocity of methanol-air mixtures obtained in a fan-stirred bomb, for u ′ = 2-6 m/s, φ= 0.8-1.4, T= 358 K and pressures up to 0.5 MPa. In combination with laminar burning velocity values previously obtained on the same rig, these measurements are used to provide better insight into the various factors affecting u t of methanol, and to assess to what degree 15 existing turbulent combustion models can reproduce experimental trends. It appeared that most models correctly accounted for the effects of turbulent rms velocity u ′ . With respect to the effects of φ and pressure, however, models accounting for flame stretch and instabilities, through the inclusion of model terms depending on thermodiffusive mixture properties and pressure, had a slight edge on simpler formulations.

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Thermodynamic Analysis of SI Engine Operation on Variable Composition Biogas-Hydrogen Blends Using a Quasi-Dimensional, Multi-Zone Combustion Model

Cited by 24 publications

References 41 publications

A combined experimental and numerical study of thermal processes, performance and nitric oxide emissions in a hydrogen-fueled spark-ignition engine

A combined experimental and numerical study of thermal processes, performance and nitric oxide emissions in a hydrogen-fueled spark-ignition engine

Experimental Study on the Burning Rate of Methane and PRF95 Dual Fuels

The turbulent burning velocity of methanol–air mixtures

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