An Eulerian/Lagrangian numerical simulation is performed on mixed sand transport. Volume averaged Navier-Stokes equations are solved to calculate gas motion, and particle motion is calculated using Newton＇s equation,...
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An Eulerian/Lagrangian numerical simulation is performed on mixed sand transport. Volume averaged Navier-Stokes equations are solved to calculate gas motion, and particle motion is calculated using Newton＇s equation, involving a hard sphere model to describe particle-to-particle and particle-to-wall collisions. The influence of wall characteristics, size distribution of sand particles and boundary layer depth on vertical distribution of sand mass flux and particle mean horizontal velocity is analyzed, suggesting that all these three factors affect sand transport at different levels. In all cases, for small size groups, sand mass flux first increases with height and then decreases while for large size groups, it decreases exponen- tially with height and for middle size groups the behavior is in-between. The mean horizontal velocity for all size groups well fits experimental data, that is, increasing logarithmically with height in the middle height region. Wall characteristics greatly affects particle to wall collision and makes the fiat bed similar to a Gobi surface and the rough bed similar to a sandy surface. Particle size distribution largely affects the sand mass flux and the highest heights they can reach especially for larger particles.
It has been a major challenge to reduce anthropogenic carbon dioxide emissions in *** the trend is the fact that increased carbon dioxide in the air causes global warming and adversely affects natural *** demands for ...
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It has been a major challenge to reduce anthropogenic carbon dioxide emissions in *** the trend is the fact that increased carbon dioxide in the air causes global warming and adversely affects natural *** demands for lowering the burdens on the environment will continue to grow steadily.
Marangoni condensation attracts much attention in recent years, due to the high heat transfer coefficient and pseudo-dropwise condensation mode which could be maintained for a long *** present study focused on the eff...
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Marangoni condensation attracts much attention in recent years, due to the high heat transfer coefficient and pseudo-dropwise condensation mode which could be maintained for a long *** present study focused on the effect of tube diameters on Marangoni condensation heat transfer in the case of ethanol-water mixture vapors condensation.
Large amounts of energy are consumed during the manufacturing of cement especially during the calcination process which also emits large amounts of CO2. A large part of the energy used in the making of cement is relea...
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Large amounts of energy are consumed during the manufacturing of cement especially during the calcination process which also emits large amounts of CO2. A large part of the energy used in the making of cement is released as waste heat. A process to capture CO2 by integrating the recovery and utilization of waste heat has been designed. Aspen Plus software was used to calculate the amount of waste heat and the efficiency of energy utilization. The data used in this study was based on a dry process cement plant with a 5-stage preheater and a precalciner with a cement output of 1 Mt/y. According to the calculations： 1） the generating capacity of the waste heat recovery system is 4.9MW. 2） The overall CO2 removal rate was as high as 78.5%. 3） The efficiency of energy utilization increased after the cement producing process was retrofitted with this integrated design.
The feedwater temperature of thermal power unit always decreases with the electrical *** order to solve this problem, the ejector heat pump is integrated with the regenerative *** live steam is used to inject the extr...
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The feedwater temperature of thermal power unit always decreases with the electrical *** order to solve this problem, the ejector heat pump is integrated with the regenerative *** live steam is used to inject the extraction steam of regenerative system, then the mixture steam is led to the added heater (working in low load condition, named as low load condition heater bellow) to heat the feedwater.
Mg and Mg-based metal hydrides are viewed as one of the most promising hydrogen storage materials due to their high capacity,light weight,low price and little impact on the ***,the practical application is obstructed ...
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Mg and Mg-based metal hydrides are viewed as one of the most promising hydrogen storage materials due to their high capacity,light weight,low price and little impact on the ***,the practical application is obstructed by their high stability,which results in the bad kinetics and high reaction temperature,especially the high operating temperature.
The paper presents a method for monitoring CO 2 leakage in geological carbon dioxide sequestration. The unsteady state dispersion of leakage CO 2 from geosequestration simulation results showed that the ensemble trend...
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The paper presents a method for monitoring CO 2 leakage in geological carbon dioxide sequestration. The unsteady state dispersion of leakage CO 2 from geosequestration simulation results showed that the ensemble trend of elevated concentration caused by CO 2 leakage can be viewed as a concentration step change perturbation to the background variation and the initial stage of dispersion process is an increasing variation. The correlation between O 2 and CO 2 variation is well linear if there is no leakage. The external linear perturbation decreases the correlation coefficient. Moreover, too large step change concentration will also reduce the average correlation coefficient. Therefore, online correlation analysis between O 2 and CO 2 in atmosphere is useful to distinguish the leakage CO 2 from complex background variation especially at the beginning of leakage occurring.
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