Ignition delay times of the 1-pentene/O2/Ar mixtures and n-pentane/O2/Ar mixtures were measured behind the reflected shock wave at 10 atm, stoichiometric equivalence ratio, in the temperature range of 1100 K to 1580 K...
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Ignition delay times of the 1-pentene/O2/Ar mixtures and n-pentane/O2/Ar mixtures were measured behind the reflected shock wave at 10 atm, stoichiometric equivalence ratio, in the temperature range of 1100 K to 1580 K. Empirical correlations of the ignition delay time for 1-pentene and n-pentane were obtained through regression analysis. The simulations with the updated natural gas model show well agreement with the experimental data. Both the experimental and simulation results show a crossover in the ignition delay time of these two mixtures. Reaction pathways and sensitivity analysis are conducted to understand the oxidation process of 1-pentene and n-pentane. The chain branching reaction R1(H+O2O+OH) shows a strong promoting effect while the resonantly stablized allyl radical may be responsible for the longer ignition delay time of 1-pentene in the high temperature region.
Measurement on turbulent premixed CH4/H2/air flames was studied experimentally. Hydrogen blending ratio is defined as the ratio of hydrogen to fuel, while CO2 dilution ratio is defined as the mole fraction of CO2 to t...
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Flame front structure of turbulent premixed CH4/air and C3H8/air flames was obtained using OH-PLIF technique, laminar flame properties were calculated and the effect of turbulence intensity on turbulent flame structur...
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Flame front structure of turbulent premixed CH4/air and C3H8/air flames was obtained using OH-PLIF technique, laminar flame properties were calculated and the effect of turbulence intensity on turbulent flame structure and flame speed was analyzed. The results showed that the flame front wrinkled was promoted as the turbulence intensity increases. The correlation between flame speed and turbulence intensity was obtained.
Consisting of steam cooler, condensation zone and drain cooler, the three-stage feedwater heater is widely used in the thermal power plants. To study the variable condition characteristics of three-stage feedwater hea...
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As one of the most promising clean alternative fuels, natural gas has been widely used in automobile engines. However, due to the slow burning velocity of natural gas and its poor lean-burn ability, hydrogen is often ...
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As one of the most promising clean alternative fuels, natural gas has been widely used in automobile engines. However, due to the slow burning velocity of natural gas and its poor lean-burn ability, hydrogen is often added to improve its combustion behavior. Researches on the fundamental laminar premixed flame characteristics of CH4/H2 blends are of great significance to understand the combustion process in practical combustors. The intrinsic instability of laminar flame is one of the classic issues in flame dynamics, which presents the dynamic response of laminar premixed flamelets to weak perturbations. By studying dynamic mechanism of intrinsic instability, we can estimate the burning velocity more accurately and gain a deeper insight into the turbulent combustion process in spark ignition engines. In this study, the cellular instabilities of laminar premixed CH4/H2/air flat flames were studied using McKenna burner with OH-PLIF technique. It was found that the addition of H2 can broaden the lean combustion limit on flat flame burner with which the cellular instabilities were brought. The digital and OH-PLIF images were obtained to calculate the quantitative parameters of cellular length scale, which is associated with the properties of fuel mixtures such as Lewis number, Markstein number et al. Through the theoretic analysis, we make a thorough investigation on the mechanism about how the cellular scales were determined.
*** Collision of two droplets in a gaseous environment plays an essential role in many natural and industrial processes,such as raindrop and cloud formation,insecticide spraying,spray painting,and spray combustion in ...
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*** Collision of two droplets in a gaseous environment plays an essential role in many natural and industrial processes,such as raindrop and cloud formation,insecticide spraying,spray painting,and spray combustion in various liquid-fueled *** the most symmetrical event,namely the head-on collision between two identical droplets,it has been experimentally and theoretically-demonstrated that,
作者:
Ren, YuxunJing, DengweiXi'An Jiaotong University
International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering 28 Xianning West Road Xi'an Shaanxi710049 China
When dispersed in water, nanoscale photocatalysts can aggregate into microscale secondary particles due to their high surface energy. The interaction between the incident photons and the aggregated particles is expect...
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To better understand the MELCOR oxidation and degradation models, past work compared the MELCOR model to a CORA experiment (CORA Test 13). These MELCOR analyses specifically focused on fuel bundle heatup and clad oxid...
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To better understand the MELCOR oxidation and degradation models, past work compared the MELCOR model to a CORA experiment (CORA Test 13). These MELCOR analyses specifically focused on fuel bundle heatup and clad oxidation when compared to CORA test data. The comparison allowed the authors to investigate differences between hydrogen generation data and simulation results. Several potential reasons were considered for hydrogen generation rate differences, including MELCOR input power, heat transfer modeling, the clad solid-phase oxidation model, and the gaseous steam diffusion model. This work focuses on the possible uncertainty in the clad oxidation models used in MELCOR. First, the MELCOR nodalization approach for the CORA test was reviewed. Then, the temperature history and spatial variation were examined. One main focus was to consider other clad solid-phase oxidation models to compare the MELCOR models. This was accomplished by developing a separate model, MYCOAC, using MELCOR temperature predictions as input. Finally, the mass transfer resistance of steam diffusion to the clad surface was examined and found to be a small effect. While the Baker-Just solid-phase oxidation model showed better agreement with CORA data at low temperatures, the conclusion in this paper is that the oxidation models are not the major source of uncertainty in hydrogen generation rate differences. Future work will focus on heat transfer modeling of the CORA test.
Labyrinth seal is a key component for the safe and reliable operation of a turbine unit. This paper sets up a three-dimensional numerical model of a labyrinth seal with a tilting rotor based on a compressor eye seal w...
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