A mixed-domain, two-phase flow, non-isothermal model is developed to study the water transport phenomena, which has significant effects on the performance of PEM fuel cells. Modelling results show that: the total wate...
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A mixed-domain, two-phase flow, non-isothermal model is developed to study the water transport phenomena, which has significant effects on the performance of PEM fuel cells. Modelling results show that: the total water concentration is decreasing along the channel in anode, while it is increasing in cathode, flooding is most likely to occur at the end of cathode flow channel;liquid water in cathode GDL presents opposite distribution at high current density and low current density, the saturation of liquid water is decreasing from inner side to outer side across the GDL at low current density while it is increasing at high current density.
Hydrogen production by biomass supercritical water gasification is about to develop in the future because the process is closed and clean with high gasification efficiency in addition. Low concentration sodium carboxy...
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ISBN:
(纸本)9781424448128;9781424448135
Hydrogen production by biomass supercritical water gasification is about to develop in the future because the process is closed and clean with high gasification efficiency in addition. Low concentration sodium carboxymethylcellulose (CMC) (2-3% mass fraction) can be mixed with particulate biomass and water to form a uniform and stable viscous paste which can be pumped to the continuous high-pressure reactor. In this paper, the supercritical water gasification of CMC was investigated in the tube flow apparatus to produce gas products consisting essentially of H 2 , CO, CH 4 and CO 2 .
The maximum total recovery from all gas wells are highly desired to be got and the production is to be maintained when the gas well reaches the end of its economic life. Although the injector has been known for about ...
The maximum total recovery from all gas wells are highly desired to be got and the production is to be maintained when the gas well reaches the end of its economic life. Although the injector has been known for about one century, sparse investigations have been performed on the injector of natural gas, and no structural optimization on the natural gas injectors has been reported. In the present paper, the structural parameters of natural gas injectors was optimized numerically with the motive pressure ranging from 2.5 to 3.5 MPa, induced pressure ranging from 0.5 to 1.5 MPa and discharged pressure being 1.5 MPa. The numerical results showed that the optimal values of diffuser gradient, mixing tube length to diameter ratio, mixing chamber length to diameter ratio and mixing chamber gradient were 40, 5, 0 and 0.25, respectively. The performance of optimized injectors was also investigated numerically. The motive natural gas flowrate increased linearly with increase of motive pressure and was independent of induced pressure. The induced flowrate and entrainment ratio of natural gas were both increased with the increase of induced pressure.
The photocatalytic oxidation of dibenzothiophen (DBT) in octance (as solvent) was conducted using O2 in air as the oxidant, TiO2 prepared by sol-gelatin method as the photocatalyst and coupling with ultrasonic. The ef...
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The photocatalytic oxidation of dibenzothiophen (DBT) in octance (as solvent) was conducted using O2 in air as the oxidant, TiO2 prepared by sol-gelatin method as the photocatalyst and coupling with ultrasonic. The effect of light distance, photocatalyst amount, reaction time, DBT initial concentration and ultasonic power on the removal of DBT were investigated deeply. The results show that the degradation rate of DBT increases by 10% by using ultrasonic. Under the conditions of TiO2 dosage of 2 g/L, air flow rate of 800 mL/min, distance of UV light of 20 cm, initial concentration of DBT of 600 mg/L, reaction time of 150 min, ultrasound power of 500 W, the degradation rate of DBT can reach up to 72.6%.
The CdS/M/TiO 2 (M = Ag, Ru, Au, Pd, and Pt) three-component nanojunction systems were constructed using a two-step photodeposition method, and evaluated for their photocatalytic activities through the degradation of ...
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A low mass flux steam jet in subcooled water was experimentally *** transition of flow pattern from stable jet to condensation oscillation was observed at relatively high water *** axial total pressures,the axial and ...
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A low mass flux steam jet in subcooled water was experimentally *** transition of flow pattern from stable jet to condensation oscillation was observed at relatively high water *** axial total pressures,the axial and radial temperature distributions were measured in the jet *** results indicated that the pressure and temperature distributions were mainly influenced by the water *** correlations corrected with water temperature were given to predict the dimen-sionless axial pressure peak distance and axial temperature distributions in the jet region,the results showed a good agreement between the predictions and ***,the self-similarity property of the radial temperature was obtained,which agreed well with Gauss *** present work,all the dimensionless properties were mainly dependent on the water temperature but weakly on the nozzle size under a certain steam mass flux.
In the present paper,the classical pressure correction method was extended into low Mach number compressible flow regime by integrating equation of state into SIMPLE *** self-developed code based on this algorithm was...
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In the present paper,the classical pressure correction method was extended into low Mach number compressible flow regime by integrating equation of state into SIMPLE *** self-developed code based on this algorithm was applied to predicting the lid-driven cavity flow and shock tube prob-lems,and the results showed good agreement with benchmark solutions and the Mach number can reach the magnitude of as low as *** attenuation of sound waves in viscous medium was then *** results agree well with the analytical solutions given by theoretical *** demonstrated that the present method could also be implemented in acoustics field simulation,which is crucial for thermoacoustic simulation.
In this article, using Gibson‐Ashby constitutive model, we suggest a new method for numerical investigation of forced convection heat transfer in porous foam metal, and try to consolidate the study for mechanical pro...
In this article, using Gibson‐Ashby constitutive model, we suggest a new method for numerical investigation of forced convection heat transfer in porous foam metal, and try to consolidate the study for mechanical property and that for thermal characteristic. By available experimental data, we simulated to two cases, namely as the transfer in porous media for diameter is 0.6 mm and porosity is 0.402, and for diameter is 1.6 mm and porosity is 0.462. The result, from our constitutive model for single forced convection heat transfer, corresponds well with the experimental data. As for pressure drop prediction in porous is in good agreement with experiment, and the error is only 5% to 10%, but for transfer is less accurate, the error is about 20%, which is acceptable in practice. So it is done that constitutive model is used to simulate the transfer property.
The laminar burning velocities and Markstein lengths of the hydrogen-air-diluent mixtures were meas-ured at different equivalence ratios (0.4―1.5), different diluents (N2, CO2 and 15%CO2+85%N2) and di-lution ratios (...
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The laminar burning velocities and Markstein lengths of the hydrogen-air-diluent mixtures were meas-ured at different equivalence ratios (0.4―1.5), different diluents (N2, CO2 and 15%CO2+85%N2) and di-lution ratios (0, 0.05, 0.10 and 0.15) by using the outwardly expanding flame. The influences of flame stretch rate on the flame propagation characteristics were analyzed. The results show that both the laminar burning velocities and the Markstein lengths of the hydrogen-air-diluent mixtures decrease with the increase of dilution ratio. The decrease in Markstein lengths means that adding diluents into the hydrogen-air mixtures will decrease the diffusional-thermal instability of the flame front. For a specified dilution ratio, the laminar burning velocities give their maximum values at an equivalence ratio of 1.8. The Markstein lengths increase with the increase of the equivalence ratio monotonously regardless of the diluents. The study shows that CO2 as the diluent has a greater impact on the laminar flame speed and the flame front stability than N2 as the diluent.
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