Flow Field Simulation And Structure Optimization Of Modular Solid Oxide Fuel Cell Short Stack

Planar solid oxide fuel cell (SOFC) is considered to be a promising energyconversion device. For reactions in SOFC’s working processes are complicated,comparing with traditional experimental methods, the numerical simulation methodhas higher efficiency, lower cost, higher accuracy and is more easy to control. Thusthe numerical simulation method is becoming more widely used in SOFC’s researchfield.The traditional method of SOFC’s construction is to pile dozens of cell units intoa SOFC stack, which can output larger power. However, the practice proves that themethod has its defects. Thus, this paper illustrates unique advantages of the modularshort stack in SOFC generating system’s development. And with the application ofcomputational fluid dynamics (CFD) method, this paper mainly introduces structureoptimization analysis of flow path within specific modular planar SOFC short stack.All the researches are expected to provide optimized construction parameters ofmodular stack for engineering practice.In chapter one, firstly, the global energy crisis and environmental problems areintroduced briefly. Then, the solid oxide fuel cell (SOFC) is introduced in details,following introduction of fuel cell. At last, overseas and domestic research status ofSOFC’s numerical simulation are presented.In chapter two, firstly, transport models within main components of typicalSOFC stack are listed briefly. Then, a series of common flow path designs aresummarized in detail. Finally, the function and characteristics of CFD method appliedin this paper are introduced in general.In chapter three, unique advantages in construction of SOFC generatingsystem,which has lager output power, by using of modular stack, are analyzed firstly.Then, according to the large scale stack model reported by Julich, a real flow pathmodel of a10-cell stack with counter-flow arrangement pattern is established. Finally,many geometric parameters, such as the inlet/outlet manifold positions, configurationsand radii,are investigated and optimized systematically through the computationalfluid dynamic method.In chapter four, structure of flow path within a general practical20-cell modularSOFC short stack are analysed. Particularly, the geometric parameters of air and fuelmanifold configurations, manifold radii, feed and exhaust header widths are chosen and optimized for both the co and counter-flow arrangement patterns of this stack.The stack flow uniformity index Γ is applied to characterize the air and fuel flowdistribution quality among the20unit cells, and the standard deviation factorσ cisapplied to evaluate the variation of the mass flow rates of the22rib channels withineach unit cell.In chapter5, main contents of this paper are summarized.