In this paper, the exothermic distribution of fuel was studied detailedly through conducting thermal equilibrium experiment when the vehicle gasoline engine was at different working conditions. Considering the charact...
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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.
Detailed Laser-Doppler Velocimeter (LDV) measurements have been carried out in a turbulent rectangular channel flow with smooth and rough surfaces at different Reynolds numbers. The measured distributions of turbulenc...
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ISBN:
(纸本)9781617829130
Detailed Laser-Doppler Velocimeter (LDV) measurements have been carried out in a turbulent rectangular channel flow with smooth and rough surfaces at different Reynolds numbers. The measured distributions of turbulence statistics across the half channel height at different wall conditions, including mean velocity, turbulence intensity, skewness factor, flatness factor and Reynolds shear stress are all reported and compared. The turbulent statistical quantities on different surfaces exhibit significant differences in both the inner and the outer region, which suggests that the roughness element has an important role on turbulent flow structure extending into the whole layer. There is a significant increase in the streamwise turbulence intensity and a slight increase in the normal turbulence intensity and the Reynolds shear stress over the rough surface. The profiles of the streamwise skewness factor become flatter over the rough walls, while the flatness factor distributions are nearly the same for different surfaces.
In order to investigate the special heat transfer characteristics of supercritical water in the entrance region, series of experiments have been conducted in 3-m and 6-m long vertical upward tubes with 20.0-mm interna...
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Oxy-fuel combustion is one of the near-zero emission clean coal technologies, which can realize large-scale CO2 capture. In this paper, catalyzed reactivities of synthetic model coal incorporating Fe 2O3, TiO2, and Mn...
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Oxy-fuel combustion is one of the near-zero emission clean coal technologies, which can realize large-scale CO2 capture. In this paper, catalyzed reactivities of synthetic model coal incorporating Fe 2O3, TiO2, and MnO2 under oxy-fuel conditions have been investigated using thermal analysis method. Experimental results show that all three catalysts present a certain extent catalytic action on the combustion behaviors of synthetic model coal under oxy-fuel conditions. The catalytic activity in main combustion process of model coal could be described as follows: Fe2O3 > TiO2 > MnO2. The increase of catalyst content causes the model coal combustion process to slightly shift to lower-temperature zone. The ignition temperature Ti shows almost no variation as Fe2O 3 or TiO2 is added into the samples. The catalysts present a not very obvious catalytic activity on the pyrolysis behaviors of synthetic model coal. In addition, TiO2 shows the greatest catalytic activity on the model coal gasification performance, while MnO2 plays an unfavorable role. The catalytic activity in gasification process of model coal could be described as follows: TiO2 > Fe2O3 > MnO2.
Based on the fundamental conservation principles-the mass,momentum,and energy conservation equtions of liquid films and the momentum conservation equation of vapor core,a theoretical three-fluid model has been develop...
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Based on the fundamental conservation principles-the mass,momentum,and energy conservation equtions of liquid films and the momentum conservation equation of vapor core,a theoretical three-fluid model has been developed to predict the dryout point of upward annular flow in vertical narrow annuli with bilateral *** range of the parameters are:pressure from 0.5 to 5.0 MPa;mass flow Through numerically solving the model,the relationships among the parameters of the critical quality (Xc),critical heat flux (QCHF),mass flow rate,system pressure,and the ratio of heat flux on the inner wall of the outer tube to that on the outer wall of the inner tube (qo/qi) are obtained and *** predicted results accurately match with the experimental *** a fixed qo,Xc will increase with the decreases in the gap size and the tube curvature when the dryout point occurs on the outer wall of the inner ***,for a fixed qi,when the dryout point occurs on the inner wall of the outer tube,the parametric trend is *** the dryout point on the inner and outer walls occurs simultaneously,Xc reaches a peak value,and the ratio of qo/qi at this position changes with the gap size and the tube curvature.
Pyridine has been chosen as the nitrogenous model fuel to research the effect of metal oxide (CaO, MgO and Fe2O3) on the emission of nitrogen oxides in the range of fluidized bed combustion temperature. The experiment...
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Pyridine has been chosen as the nitrogenous model fuel to research the effect of metal oxide (CaO, MgO and Fe2O3) on the emission of nitrogen oxides in the range of fluidized bed combustion temperature. The experiment was presented in a fixed bed reactor with metal oxide layer, and FT-IR gas analyzer was used to monitor the emission of N2O and NO. When there is no metal oxide loaded, results show that the maximum peak of N2O is at 725°C. Under the rich oxygen condition, NO increases monotonically with temperature increasing, however, under the lean oxygen condition there is a maximum peak of NO at 675°C, NO decreases to a minimum value at 725°C, and then increases slowly. With the addition of metal oxide, the loaded experimental results show that the addition will not change the general trend of nitrogen oxides, but it affects the emission in a certain extent and the effect has relation to temperature, oxygen atmosphere and metal oxide added. Under the lean oxygen condition, both CaO and Fe2O 3 inhibit the formation of N2O and NO in all temperature range;the effect of Fe2O3 on NO is negligible above 900°C;MgO inhibits N2O at temperature higher than 725°C, and inhibits NO only from 625°C to 700°C. Under the rich oxygen condition, CaO and MgO decrease the N2O emission efficiently, but Fe 2O3 can only act at the temperature higher than 700°C. For the NO emission, CaO and MgO inhibit NO just above 775°C, however, Fe2O3 promotes NO greatly especially below 700°C, and it even promotes NO2 to 122.65ppm at 625°C. The results and discussion are helpful to demonstrate the effect of metal elements on the emission of nitrogen oxides in fluidized bed combustion.
Mixed convection heat transfer in heated tubes has been studied extensively in the past decades, which is widely used in various industrial fields such as cooling of a nuclear reactor core. The secondary flow, which i...
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In this paper, solar power tower stations with different configurations of steam generators are proposed, and a detailed dynamic model of one-dimensional distributed parameters is established and verified. The respons...
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Zhundong coalfield has a super-large reserve of coal resources. However, its high-alkali feature deteriorates the phenomenon of ash deposition and slagging in coal-fired boilers. Oxy-fuel combustion is a clean and eff...
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