Understanding the interaction between a fluid and a solid phase is of fundamental importance to the design of an adsorption process.Because the heat effects associated with adsorption are comparatively large,the as-su...Understanding the interaction between a fluid and a solid phase is of fundamental importance to the design of an adsorption process.Because the heat effects associated with adsorption are comparatively large,the as-sumption of isothermal behavior is a valid approximation only when uptake rates are relatively slow.In this article,we propose to determine when it is needed to choose the isothermal or non-isothermal assumption according to two physical parametersα（ratio convection/capacity） andβ（quantity of energy/capacity） .The proposed problem is solved by a mathematical method in the Laplace domain.Whenα→∞（infinitely high heat transfer coefficient） or β→0（infinitely large heat capacity） ,the limiting case is isothermal.When the diffusion is rapid（α10） the kinetics of sorption is controlled entirely by heat transfer.If the adsorption process is to be used as a heat pump,it shall be represented by an isotherm model withαandβas high as possible.展开更多
A 3-D modeling of FEA （finite element analysis） design provides for high-speed synchronous with PMs （permanent magnets） applied in aerospace application will be examined under design considerations ofn = 12,000 rp...A 3-D modeling of FEA （finite element analysis） design provides for high-speed synchronous with PMs （permanent magnets） applied in aerospace application will be examined under design considerations ofn = 12,000 rpm, short-duty operation, and etc. for an ARWM （aerospace retraction wheel motor）. First, lumped-elements will be fine-tuned following numerical method results is reported steady-state and transient solutions. Besides, the equations of thermal modeling such as Re, N,,, G,. and Pr numbers in order to calculate heat-transfer coefficient of convection on the rotor and stator surfaces in the air-gap have calculated. This section illustrates the temperature distribution of each point in a clear view. By CFD （fluid dynamic analysis） analysis, the fluid dynamics were modeled, pressure and velocity streamlines of cooling-flow have analyzed. An optimization algorithm was derived in order to have optimized number of water-channels as well. Second, calculation of nodal and tangential forces which deal with mechanical stresses of the ARWM have represented. The paper discusses an accurate magnetic-field analysis that addresses equivalent stress distribution in the magnetic core through using the transient FEA to estimate motor characteristics. The whole model shear and normal mechanical stresses and total deformation oftbe ARWM has been investigated by transient FEA. The end-winding effects were included by the authors.展开更多
In general,heat transfers can be classified into two categories according to the purposes of object heating or cooling and the heat to work conversion.Recently,a new physical quantity,entransy(or potential energy),was...In general,heat transfers can be classified into two categories according to the purposes of object heating or cooling and the heat to work conversion.Recently,a new physical quantity,entransy(or potential energy),was proposed to describe the ability of heat transfer with the former purpose.This paper addresses the concept of potential energy in terms of the heat transfer processes for the latter purpose,named the conversion potential energy.The physical meaning of this newly introduced concept is the potential energy for the heat to work conversion stored in the equivalent mass of heat(thermomass) derived on the basis of the Einstein's special theory of relativity.The dissipation of conversion potential energy occurs during the real irreversible heat to work conversion processes as a measure of the conversion irreversibility.Finally,a heat to work conversion problem of a heat exchanger group is provided to show that the minimum conversion potential energy dissipation rate can be used as an optimization criterion for the heat transfer performance with the purpose of the heat to work conversion.展开更多
Interfacial transfer plays an important role in multi-phase chemical processes. However, it is difficult to describe the complex interfacial transport behavior by the traditional mass transfer model. In this paper, we...Interfacial transfer plays an important role in multi-phase chemical processes. However, it is difficult to describe the complex interfacial transport behavior by the traditional mass transfer model. In this paper, we describe an interfacial mass transfer model based on linear non-equilibrium thermodynamics for the analysis of the rate of interfacial transport. The interfacial transfer process rate J depends on the interface mass transfer coefficient K, interfacial area A and chemical potential gradient at the interface. Potassium compounds were selected as model systems. A model based on linear non-equilibrium thermo-dynamics was established in order to describe and predict the transport rate at the solid-solution interface. Together with accurate experimental kinetic data for potassium ions obtained using ion-selective electrodes, a general model which can be used to describe the dissolution rate was established and used to analyze ways of improving the process rate.展开更多
文摘Understanding the interaction between a fluid and a solid phase is of fundamental importance to the design of an adsorption process.Because the heat effects associated with adsorption are comparatively large,the as-sumption of isothermal behavior is a valid approximation only when uptake rates are relatively slow.In this article,we propose to determine when it is needed to choose the isothermal or non-isothermal assumption according to two physical parametersα（ratio convection/capacity） andβ（quantity of energy/capacity） .The proposed problem is solved by a mathematical method in the Laplace domain.Whenα→∞（infinitely high heat transfer coefficient） or β→0（infinitely large heat capacity） ,the limiting case is isothermal.When the diffusion is rapid（α10） the kinetics of sorption is controlled entirely by heat transfer.If the adsorption process is to be used as a heat pump,it shall be represented by an isotherm model withαandβas high as possible.
文摘A 3-D modeling of FEA （finite element analysis） design provides for high-speed synchronous with PMs （permanent magnets） applied in aerospace application will be examined under design considerations ofn = 12,000 rpm, short-duty operation, and etc. for an ARWM （aerospace retraction wheel motor）. First, lumped-elements will be fine-tuned following numerical method results is reported steady-state and transient solutions. Besides, the equations of thermal modeling such as Re, N,,, G,. and Pr numbers in order to calculate heat-transfer coefficient of convection on the rotor and stator surfaces in the air-gap have calculated. This section illustrates the temperature distribution of each point in a clear view. By CFD （fluid dynamic analysis） analysis, the fluid dynamics were modeled, pressure and velocity streamlines of cooling-flow have analyzed. An optimization algorithm was derived in order to have optimized number of water-channels as well. Second, calculation of nodal and tangential forces which deal with mechanical stresses of the ARWM have represented. The paper discusses an accurate magnetic-field analysis that addresses equivalent stress distribution in the magnetic core through using the transient FEA to estimate motor characteristics. The whole model shear and normal mechanical stresses and total deformation oftbe ARWM has been investigated by transient FEA. The end-winding effects were included by the authors.
基金supported by the NUAA Research Funding (Grant No. NS2012142)
文摘In general,heat transfers can be classified into two categories according to the purposes of object heating or cooling and the heat to work conversion.Recently,a new physical quantity,entransy(or potential energy),was proposed to describe the ability of heat transfer with the former purpose.This paper addresses the concept of potential energy in terms of the heat transfer processes for the latter purpose,named the conversion potential energy.The physical meaning of this newly introduced concept is the potential energy for the heat to work conversion stored in the equivalent mass of heat(thermomass) derived on the basis of the Einstein's special theory of relativity.The dissipation of conversion potential energy occurs during the real irreversible heat to work conversion processes as a measure of the conversion irreversibility.Finally,a heat to work conversion problem of a heat exchanger group is provided to show that the minimum conversion potential energy dissipation rate can be used as an optimization criterion for the heat transfer performance with the purpose of the heat to work conversion.
基金supported by the Chinese National Key Technology Research and Development Program (2006AA03Z455)the National Natural Science Foundation of China (NSFC)+3 种基金the National Natural Science Foundation of China (20976080, 20736002)the Research Grants Council(RGC) of Hong Kong Joint Research Scheme (JRS) (20731160614)Program for Changjiang Scholars and Innovative Research Team in University (IRT0732)National Basic Research Program of China (2009CB226103)
文摘Interfacial transfer plays an important role in multi-phase chemical processes. However, it is difficult to describe the complex interfacial transport behavior by the traditional mass transfer model. In this paper, we describe an interfacial mass transfer model based on linear non-equilibrium thermodynamics for the analysis of the rate of interfacial transport. The interfacial transfer process rate J depends on the interface mass transfer coefficient K, interfacial area A and chemical potential gradient at the interface. Potassium compounds were selected as model systems. A model based on linear non-equilibrium thermo-dynamics was established in order to describe and predict the transport rate at the solid-solution interface. Together with accurate experimental kinetic data for potassium ions obtained using ion-selective electrodes, a general model which can be used to describe the dissolution rate was established and used to analyze ways of improving the process rate.
