Numerical simulation was implemented on a tubular solid oxide fuel cell (SOFC) with indirect internal reformer used in the demonstration projects of Siemens-Westinghouse. The Navier-Stokes equations and the charge equation were solved by means of a generalized, threedimensional complete polarization electrochemical model for SOFC. The distributions of both the molar fraction of gaseous species and the temperature were presented. The characteristic of thermal energy generation was analyzed based on the simulation results. The electrochemical process was exothermic reaction, which contributed 82.7% in the total heat generation. The ohmic heat possessed 17.3% in the total heat generation. About 47.3% of the generated heat in the cell was absorbed by the reforming reaction. The air flow took away 36.6% the generated heat and the remainder 16% was taken away by the fuel flow.

This paper investigates the usage of an interior inlay viscous fluid unit as a new vibration suppression method for flexible structures via numerical simulations. The first and second modes of vibration for a beam have been calculated using the commercial computational fluid dynamic package Fluent6.1, together with the liquid surface distribution and the fluid force. The calculated results show that the inlay fluid unit has suppressive effects on flexible structures. The liquid converges self-adaptively to locations of larger vibrations. The fluid force varies with the beam vibration at a phase difference of more than 1801. Thus the fluid force suppresses the beam vibration at most of the time.

The viscous work generated by the rotating components of a seal not only represents a direct loss of power but also causes an increase in the total temperature of fluid (windage effect). In order to study the discharge and total temperature increase characteristics of the stepped labyrinth seals with smooth and honeycomb lands, 3D Reynolds-averaged Navier-Stokes solutions from CFX is used in this work. At first, the influences of the inlet preswirl, leakage flow rate, and rotational speed on the total temperature increase in the convergent and divergent stepped labyrinth seals with smooth and honeycomb lands are conducted. The obtained 3D numerical results are well in agreement with the referenced experimental data. It shows that the utilized numerical approach has sufficient precision to predict the total temperature increase in seals. Then, a range of pressure ratios and four sizes of sealing clearance are performed to investigate the effects of sealing clearances and pressure ratio impact on the discharge and total temperature increase of the stepped labyrinth seals with honeycomb and smooth liners.

The hybrid solid oxide fuel cell (SOFC) and gas turbine (GT) system is a promising concept in the future power generation for its highperformance and low-emission. The dynamic model for the hybrid system of integrated SOFC and recuperative GT with air reheating component is presented in this work. A dynamic model was put forward based on the conservation equations of mass, energy and force through the whole plant, with specific source terms in different types of components. The SOFC was modeled on the basis of the Exponential Decay function and the Exponential Associate function, which describe the characteristics of the parameters distribution within the SOFC. A cubic curve was employed to denote the compressor pressure characteristics. In the turbine model, the relation between the work done and the inlet condition of turbine was determined according to the turbine nozzle work characteristics. The developed system model was programmed and implemented in the simulation tool Aspen Custom Modeler. The current density of SOFC was selected as disturbance variable during the dynamic simulation using the developed dynamic model. The responses of the SOFC air inlet temperature, SOFC outlet temperature, and turbine inlet temperature, the output voltage, and the gas species molar fractions at the outlet of SOFC were presented. The obtained results show that the presented dynamic model can be able to simulate the system dynamic track reasonably.

A lumped, non-linear control-oriented dynamic model for the solid oxide fuel cell has been developed. The exponential decay function and the exponential associate function are introduced to fit the distribution characteristics of fuel cell state variables in the flow direction of the gases in order to account for the effect of spatial variation of fuel cell parameters in the dynamic model. It is integrated into the dynamic model by three characteristic parameters of the fitting function, which are determined via numerical simulations. A planar solid oxide fuel cell with co-flow has been used to evaluate the accuracy and applicability of the current dynamic model. The dynamic model is programmed and implemented using the SIMULINK software. The simulation results indicate the model has good service quality to predict the state variables and the performance of the solid oxide fuel cell.