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...
详细信息
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 ...
详细信息
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.
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...
详细信息
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 ...
详细信息
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...
详细信息
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.
暂无评论