Entity

Time filter

Source Type


Tu Z.-K.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing
Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics | Year: 2012

The simplified three-dimensional model of the cathode gas flow field in proton exchange membrane (PEM) fuel cell was established to investigate the flow distribution characteristics in cell stacks under different gas inlet types and different manifold pipe sizes, and improved scheme for more uniformly flow distribution was proposed through the use of the non-uniform depth channels in signal cells. The results show that the double-inlet gas field types perform better than the single-inlet types, and the double-inlet and double-outlet types can obtain the best performance in flow distribution with the lowest power consumption. The flow distribution can become more uniform with the increase of the manifold pipe width. The proper use of the non-uniform depth channels can improve the flow distribution performance effectively. Source


Tu Z.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2012

The start-up criterion of the capillary loop system with phase change was obtained by analyzing the force equilibrium of the capillary liquid column, and a three-dimensional thermal conducting model of the evaporator is established to investigate the start-up characteristics of the system. The results show that the preheating time of the evaporator decreases with increasing of the heat flux; reducing the height of the liquid compensation chamber can speed up the startup process of the evaporator and the effect would be more significant under a lower startup heat flux; besides, the preheating time can be shortened by reducing the width of the steam channels under lower startup heat flux, while the effects are not significant under high heat flux. Source


Deng C.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing | Tong L.,Huaxia College | Xiao J.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing | Benard P.,University of Quebec at Trois - Rivieres
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2011

The direct numerical simulation (DNS) method, in which there is not any experimental model used for the porous media, is proposed to simulate fluid flow in porous media. A two dimensional DNS mode is implemented based on a computational fluid dynamics (CFD) software Fluent to investigate the flow resistance and pressure drop in the porous media. Two geometrical configurations, i. e., inline and staggered geometrical configurations packed with cylindrical particles, are used in the simulations. The pressure drop for inline geometrical configurations simulated from DNS is 53.5 Pa, which approaches the valve 55.6 Pa obtained from the Ergun equation model with the original coefficients of A=150, B=1.75. The pressure drop for staggered geometrical configurations simulated from DNS is 65.1 Pa, which approaches the valve 62.1 Pa obtained from the Ergun equation model with the modified coefficients of A=180, B=1.80. The staggered geometrical configuration with cylindrical particles is more exact than the inline configuration for modeling the real porous media materials. Therefore, the DNS results confirm that the modified coefficient pair (A=180, B=1.80) is more suitable for Ergun equation model than the original coefficient pair (A=150, B=1.75). The DNS method proposed in this paper can be further applied to predicate the coefficients for Ergun equation or to develop other porous model, by using different geometrical configurations packed with different shape of particles. Source


Zhang N.,Chengdu University of Technology | Xiao J.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing | Zhan Z.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing | Pan M.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2010

The porosity distribution of Gas diffusion layer (GDL) has significant influence on the performance of proton exchange membrane (PEM) fuel cell. In this paper, A three-dimensional fuel cell model is created and solved by means of finite control volume method. Several random distributions such as normal distribution, uniform distribution and single distribution for gas diffusion layer porosity are considered in the model. The performance of fuel cell with different porosity distributions is also studied. The result show that, the single porosity distribution of GDL has the best mass transport and uniform temperature distribution of the MEA, so the performance of this fuel cell is the better. Source


Tu Z.-K.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing | Pan M.,State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing | Liu W.,Huazhong University of Science and Technology | Liu Z.-C.,Huazhong University of Science and Technology | Wan Z.-M.,Hunan Institute of Science and Technology
International Journal of Heat and Mass Transfer | Year: 2012

A mathematical model based on the Lucas-Washburn equation has been developed to address the relations of the capillary height, capillary radius and the heat flux in a capillary column and the equation is extended to a capillary loop for investigating the stability of the condensing interface with phase change by some simplifications in the paper. The stability of the condensing interface is studied by introducing a small disturbance into capillary height. The dynamics performances of the condensing interface under three different operating conditions are discussed in this paper. The results show that the condensing interface presents high instability under non-gravitational condition, while the stability can be enhanced in gravitational condition with a certain gravitational height, moreover, regular vibration can be formed on the condensing interface due to the periodic oscillation of the pressure in the system. © 2011 Elsevier Ltd. All rights reserved. Source

Discover hidden collaborations