Adrian H.M. Verkooijen

Flow Distribution in the External Manifold of SOFC Stack

In this paper fluid dynamic behaviors of cathode gas flow in an external gas manifold of a planar solid oxide fuel cell (SOFC) stack are simulated to investigate the overall pressure variation and flow distribution. External manifold models are built in three dimensions for a 60-cell planar SOFC stack. Cell units of the stack are treated as porous media with appropriate resistances, which were determined by the previous results of cell modeling. In order to simplify this model, electrochemical reactions, heat and mass transport phenomena are ignored inside cells. The flows of cathode gas in the external manifolds of stack are modeled by means of computational fluid dynamics (CFD) methods. A commercial CFD package “Fluent” was used for geometry creation, grids generation of flow volume interiors, solving mass, momentum equations, plotting computational results. The detailed results of pressure variation and flow distribution of gases in the stack were achieved. The effects of different designs and parameters such as a gas distributor inside the external manifold, the permeability of porous media in cells and cathode gas feeding rate on gas distribution and pressure variation are studied. Comparison of different cases is carried out by the modeling results. Modeling results show for the proposed stack design in this paper the additional gas distributor located in the center of the inlet manifold and a rise of resistance in cells can respectively enhance the uniformity of flow distribution over 60 cells.Copyright

Solid oxide fuel cell integrated with biomass gasification for power generation for rural areas in China

Fuel cells coupled with biomass gasifiers can offer the potential of highly efficient and renewable power generation in an environmentally friendly and CO2-neutral manner. Three key aspects, i.e. the fuel resources and fuel cell types as well as gas cleaning for this combined system were discussed to present the feasibility of applying biomass gasification (BG) based solid oxide fuel cell (SOFC) system for distributed power generation in developing countries. The performance of BG-SOFC based combined heat and power (CHP) system and future work was also presented.

Three-dimensional Modeling of Anode-supported Planar SOFC with Direct Internal Reforming

This paper presents a three-dimensional model of an anode-supported planar SOFC with corrugated bipolar plates serving as gas channels and current collector above the active area of the cell, based on the direct internal reforming reaction of methane and the electrochemical reaction of hydrogen. A co-flow system with gas mixture of methane, water vapor and a small amount of hydrogen as anode gas and air as cathode gas fed at an inlet temperature of 973K was modeled at a single cell unit level. A simple equation for the cell resistance with measured values for the quasi ohmic resistance is used for the calculation of the current density. The modeling results show the current density distribution and temperature profiles in the cell and gas concentrations profiles along the length of the cell channel. Furthermore, the temperature gradient inside the cell was investigated.

Dynamic Modeling of a Closed Cycle Gas Turbine CHP Plant With a Nuclear Heat Source

The High Temperature Gas-cooled Reactor is a promising concept for inherently safe nuclear power generation. This paper deals with dynamic modeling of the energy conversion system of a combined heat and power plant, based on a helium cooled reactor in combination with a closed cycle gas turbine system. The model will be used to design and test a control system and to analyze transients following incidents. A one-dimensional flow model describing the helium flow and the two-phase water flow is used through the whole plant, with different source terms in different pieces of equipment. A stage-by-stage model is produced for the radial compressor and axial turbine. Other models include the recuperator, water/helium heat exchangers a natural convection evaporator, valves, etc. With this model, open-loop responses from controlled parameters (shaft speed, temperatures and pressures) on changes of reactor power, valve-positions etc. have been established.© 1999 ASME