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Chen L.,Sanming University | Zhang H.,Ningbo University | Gao S.,Sanming University | Yan H.,Sanming University
Energy | Year: 2014

A new hybrid system mainly consists of a molten carbonate fuel cell (MCFC) and a Stirling heat engine is established, where the Stirling heat engine is driven by the high-quality waste heat generated in the MCFC. Based on the electrochemistry and non-equilibrium thermodynamics, analytical expressions for the efficiency and power output of the hybrid system are derived by taking various irreversible losses into account. It shows that the performance of the MCFC can be greatly enhanced by coupling a Stirling heat engine to further convert the waste heat for power generation. By employing numerical calculations, not only the influences of multiple irreversible losses on the performance of the hybrid system are analyzed, but also the impacts of some operating conditions such as the operating temperature, input gas compositions and operating pressure on the performance of the hybrid system are also discussed. The investigation method in the present paper is feasible for some other similar energy conversion systems as well. © 2013.

Zhang H.,Ningbo University | Chen L.,Sanming University | Zhang J.,Ningbo University | Chen J.,Xiamen University
Energy | Year: 2014

The model of a packed bed anode DCFC (direct carbon fuel cell) with molten carbonate as an electrolyte and graphite as a fuel is established to globally evaluate its performance. Thermodynamic-electrochemical analyses on the performance of the DCFC are implemented, in which the activation overpotential, ohmic overpotential, and concentration overpotential are taken as the main sources of voltage losses. The analytical expressions for the cell voltage, power output, efficiency, and entropy production rate are derived, from which the general performance characteristics are discussed in detail. At the anode, the ohmic overpotential in each slab resulting from the carbon phase is found to be about three orders of magnitude larger than that resulting from the electrolyte phase. The radius of the real contact area between two neighboring graphite particles decreases at an accelerating rate as one goes up in the bed, and the corresponding constriction resistance will increase at an accelerating rate. The decrease in the operating current density and anode dimension and the increase in the operating temperature will lessen the overall ohmic overpotential. The effects of the operating current density, operating temperature and anode dimension on the performance are discussed, and the optimum criteria for some important performance parameters are determined. © 2014 Elsevier Ltd.

Xiao B.,Sanming University
Modern Physics Letters B | Year: 2010

In this paper, dependence of active nucleation site density on boiling surfaces are developed. For pool boiling heat transfer, a mathematical model is derived based on statistical treatment using the probability density function of the cavity mouth radius and existing correlation for active nucleation site density, the volume of single bubble at departure, the bubble departure diameter and the bubble departure frequency. The proposed model is expressed as a function of wall superheat, the contact angle, maximum and minimum active cavities, and physical properties of fluid. It is shown that the wall heat flux can be determined by the consideration of the variation of the cavity mouth radius. A good agreement between the proposed model predictions and experimental data is found for different contact angles. It also turns out that the present model explains well the mechanism on how wettability affects the pool boiling. © 2010 World Scientific Publishing Company.

Liu J.J.,Sanming University
Energy and Environmental Engineering - Proceedings of the International Conference on Energy and Environmental Engineering, ICEEE 2014 | Year: 2015

Bamboo is a kind of annual output of high biomass material. Green Bamboo has a 12,000 kg yield per hectare, and is very suitable for the production of cellulosic ethanol.We use Green Bamboo as a kind of biomass; it will simplify the processes and reduce production costs. It is pretreated with hot water, liquid ammonia, and steam explosion. Then cellulase and amylase for hydrolysis are added. Analysis is made from the samples of hydrolysis solution and filtrate by HPLC (high performance liquid chromatography), using the Biorad Aminex HPX-87H column for glucose, xylose, and arabinose. The results showed that the glucan/xylan conversion was greatest under hot water conditions for ten minutes. They were 28.45% and 45.55% respectively, compared with untreated biomass where they increased by 111.07% and 224.23%. The research conclusion has important significance for biomass energy conversion and utilization. © 2015 Taylor & Francis Group, London.

Wu L.,Sanming University
Applied Mechanics and Materials | Year: 2010

Consider the imperfectness of mass partition coefficient for a whole car in automotive theories, a vehicle physical model with fourteen degree of freedoms under vertical and lateral road excitations is adopted as research background in this paper. With the help of force analysis of sprung mass in three dimensional space and investigations on vertical, lateral, pitch, roll and yaw motions, the ration relations of dynamical coupling between a whole suspension and four quarter suspensions are deduced and achieved. The analytical results obtained in this paper develop the theoretical content of mass partition coefficient. It will be utilized to analyze, test and control among different car suspensions in the fields of vibration, handling and steering systems in future. © (2010) Trans Tech Publications, Switzerland.

Lin R.,Sanming University | Fan C.,Shandong University
Journal of Convergence Information Technology | Year: 2012

Packet sets are a novel mathematical model, which is a set pair composed of internal Packet set X F (internal packet set X F) and outer packet set X F (outer packet set X F), and has the dynamic characteristics. Using the dynamic characteristics of packet sets, this paper gives the concept and characteristics of inward-convergence information. Moreover, a series of inward-convergence information theorems are presented and the application in the unknown information discovery and identification. Packet sets are a novel method and theory in the research of the dynamic information system.

Yan H.,Tongji University | Yan H.,Sanming University | Jin B.,Tongji University
European Physical Journal E | Year: 2013

Immersed in an ionic solution, a network of polyampholytic polyelectrolyte imbibes the solution and swells, resulting in a polyampholytic p H-sensitive hydrogel, which can respond to changes in the surrounding environmental p H. This paper formulates a continuum field theory for polyampholytic p H-sensitive hydrogels by considering the reaction of hydrogen ions with hydroxide ions, which has been ignored in our previous paper (H.X. Yan, B. Jin, Eur. Phys. J. E 35, 36 (2012)). Comparison with experimental data shows that the proposed continuum field theory, by considering that the reaction of hydrogen ions with hydroxide ions would be more reasonable, can not only give a good qualitative but also a good quantitative prediction of the dependence of swelling on p H and crosslinker. The theory is then applied to study the influence of chain entanglements, salt concentration, uniaxial tension and geometric constraint on mechanical behavior of polyampholytic p H-sensitive hydrogels. © 2013 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Xiao B.,Sanming University | Xiao B.,Hong Kong Polytechnic University | Yang Y.,Hong Kong Polytechnic University | Chen L.,Sanming University | Chen L.,Hong Kong Polytechnic University
Powder Technology | Year: 2013

Considering the effect of Brownian motion of nanoparticles, an analytical model for effective thermal conductivity of nanofluids is obtained. The formula of calculating effective thermal conductivity of nanofluids is given by taking into account the fractal distribution of nanoparticles. In the present approach, the proposed model is explicitly related to the thermal conductivities of the base fluids and the nanoparticles, the average diameter of nanoparticles, the nanoparticle concentration, the fractal dimension of nanoparticles and physical properties of fluids. It is found that the effective thermal conductivity of nanofluids increases with increasing of the concentration of nanoparticles. And the effective thermal conductivity of nanofluids for the smaller size of nanoparticles is larger than the bigger size at given concentration. A good agreement between the proposed model predictions and experimental data is found. The validity of the fractal model for effective thermal conductivity of nanofluids is thus verified. The proposed fractal model can reveal the physical mechanisms of heat transfer for nanofluids. © 2013 Elsevier B.V.

Yan H.,Tongji University | Yan H.,Sanming University | Jin B.,Tongji University
International Journal of Solids and Structures | Year: 2012

The swelling deformation behavior of polymer gels is often described in terms of the Flory-Rehner framework, in which the Flory-Rehner free energy function is based on the simplest affine network model, does not take entanglements into account. However, the real polymer networks have many chain entanglements. In this paper, a new hybrid free energy function composed of the Edwards-Vilgis slip-link model and the Flory-Huggins solution theory is presented for the prediction of the influence of chain entanglements on mechanical behavior of gels. The simulation results of mechanical behavior in free swelling, uniaxial extension, biaxial constraint and simple shear are presented. It is shown that in the nonentangled state, this new hybrid free energy function reduces to the Flory-Rehner free energy function; in the entangled state, the influence of entanglements on the mechanical behavior of gels is significant, the more entangled networks exhibit higher stress. © 2011 Elsevier Ltd. All rights reserved.

Xiao B.-Q.,Sanming University
Chinese Physics B | Year: 2013

Analytical expressions for nucleate pool boiling heat transfer of nanofluid in the critical heat flux (CHF) region are derived taking into account the effect of nanoparticles moving in liquid based on the fractal geometry theory. The proposed fractal model for the CHF of nanofluid is explicitly related to the average diameter of the nanoparticles, the volumetric nanoparticle concentration, the thermal conductivity of nanoparticles, the fractal dimension of nanoparticles, the fractal dimension of active cavities on the heated surfaces, the temperature, and the properties of the fluid. It is found that the CHF of nanofluid decreases with the increase of the average diameter of nanoparticles. Each parameter of the proposed formulas on CHF has a clear physical meaning. The model predictions are compared with the existing experimental data, and a good agreement between the model predictions and experimental data is found. The validity of the present model is thus verified. The proposed fractal model can reveal the mechanism of heat transfer in nanofluid. © 2013 Chinese Physical Society and IOP Publishing Ltd.

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