The solar chimney power plant (SCPP) has been accepted as one of the most promising approaches for future large-scale solar energy applications. This paper reports on a heat transfer model that is used to compare the ...
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The experiment was made of boiling heat transfer of FC-72 on micro-pin-finned chips with submerged jet *** experimental conditions cover two different liquid subcooling degrees (25, 35 K), three different jet velociti...
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The experiment was made of boiling heat transfer of FC-72 on micro-pin-finned chips with submerged jet *** experimental conditions cover two different liquid subcooling degrees (25, 35 K), three different jet velocities (Vj =0.5, 1, 1.5 m/s) in the direction perpendicular to chip surface.
This paper proposes a new 1D model to predict ejector performance at critical and sub-critical operational modes, while most previous 1D models have only predicted ejector performance at critical mode operation. Const...
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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,...
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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.
Experiments were conducted to study pool boiling heat transfer on ultra-light porous metal foam surfaces,with deionized water as working *** metal foams have pore densities from 30 to 60ppi(pores per inch) and thickne...
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ISBN:
(纸本)9781479933372
Experiments were conducted to study pool boiling heat transfer on ultra-light porous metal foam surfaces,with deionized water as working *** metal foams have pore densities from 30 to 60ppi(pores per inch) and thickness from2.0 to *** effects of heat flux,surface superheat,liquid temperature and characteristic parameters of metal foam on pool boiling heat transfer were *** is found that metal foam surfaces can significantly enhance pool boiling heat transfer and lower the surface superheat at the boiling *** density and thickness exists an optimal value to strengthen boiling heat *** boiling heat transfer coefficient on the metal foam surfaces is about 2~3 times of those on the plain *** significant reasons are due to the distinct nature of high porosity and multi-scale pore sizes of metal *** larger pores help to release the created vapor while the smaller pores help to suck the liquid toward the heater surface,decreasing the shear stress at the vaporliquid interface for the counter-current flow.
Combined with a simple phase change model,the Volume of Fluid(VOF)method is used for simulating the seed bubble triggered boiling in a single circular microchannel with 6.5mm *** results show that the introduction of ...
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Combined with a simple phase change model,the Volume of Fluid(VOF)method is used for simulating the seed bubble triggered boiling in a single circular microchannel with 6.5mm *** results show that the introduction of seed bubbles improves the heat transfer performance and suppresses the flow instability *** seed bubbles are triggered into the microchannel for f=2000 Hz,passing by only about five numbers of periods,the wall superheats remarkably decreased,a complete thermal equilibrium between the liquid and vapor phases is approached,the flow instability can be controlled *** the stable flow stage,the heat transfer which can reach more than 3 times the single liquid phase heat transfer dominated by the local liquid film thickness,which is the actual heat transfer length-scale in the liquid film ***,the liquid bridge region existing between the bubbles produces a week heat transfer mechanism.
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