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.

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.

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.

Cycle simulation and analysis for two kinds of SOFC/GT hybrid systems were conducted with the help of the simulation tool: Aspen Custom Modeler. Two cycle schemes of recuperative heat exchanger (RHE) and exhaust gas recirculated (EGR) were described according to the air reheating method. The system performance with operating pressure, turbine inlet temperature and fuel cell load were studied based on the simulation results. Then the effects of oxygen utilization, fuel utilization, operating temperature and efficiencies of the gas turbine components on the system performance of the RHE cycle and the EGR cycle were discussed in detail. Simulation results indicated that the system optimum efficiency for the EGR air reheating cycle scheme was higher than that of the RHE cycle system. A higher pressure ratio would be available for the EGR cycle system in comparison with the RHE cycle. It was found that increasing fuel utilization or oxygen utilization would decrease fuel cell efficiency but improve the system efficiency for both of the RHE and EGR cycles. The efficiency of the RHE cycle hybrid system decreased as the fuel cell air inlet temperature increased. However, the system efficiency of EGR cycle increased with fuel cell air inlet temperature. The effect of turbine efficiency on the system efficiency was more obvious than the effect of the compressor and recuperator efficiencies among the gas turbine components. It was also indicated that improving the gas turbine component efficiencies for the RHE cycle increased system efficiency higher than that for the EGR cycle.

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.