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.
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.
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.
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.
This article proceeds a new method which can continuously prepare emulsion by using a venturi tube, to achieve the goal of emulsify diesel oil, methane and water. The diesel oil comes in at the entrance of the venturi...
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This article proceeds a new method which can continuously prepare emulsion by using a venturi tube, to achieve the goal of emulsify diesel oil, methane and water. The diesel oil comes in at the entrance of the venturi tube. The solution of methane and water comes in at the throat of venturi tube and mixes with diesel oil to form emulsion. The preparation system is designed and the structure parameter of the venturi tube is calculated. Then FLUENT is used to do a series of numerical simulation of the flow in the venturi tube under different parameters of spread angle and ratio of length to diameter, thus deciding the best parameters which are 8 degree and 1.25. The basic data for the design of experimental system is provided.
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.
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