【作者】 徐泽亚；

【导师】 杨晨；

【作者基本信息】 重庆大学 ， 动力机械及工程， 2006， 硕士

【摘要】 燃料电池(FC)是一种高效低污染的新型能量转换装置,其发电效率可达到50%~60%,有非常好的发展前景,目前很多国家都很重视对燃料电池的研究开发工作。固体氧化物燃料电池(SOFC)是燃料电池的一种,由于它的排气温度很高,有非常大的余热利用价值,若将SOFC和微型燃气轮机(MGT)组成联合循环装置,可以大大提高热效率,充分利用能源,还可以有效降低排放,减少污染。因此,由燃料电池和微型燃气轮机组成的联合循环装置具有强大的生命力,对其进行性能分析具有重要的现实意义。由于燃料电池系统工作在高温、封闭、复杂的环境下,内部状态测量极为困难,试验分析代价很高,有时甚至是不可能的。为提高其性能并确保其安全、长寿命运行,本文采用数值分析的方法,建立燃料电池/微透平联合循环系统的数学模型来对系统进行性能仿真分析。本文研究工作主要分三个部分:第一部分对一个以天然气为燃料采用内部重整的管型SOFC堆进行了理论和性能分析。计算分析了系统参数(电流密度、工作温度和压力以及燃料流量等)对电池性能(电池电压、发电量及发电效率等)的影响。结果表明:增加电池的工作温度和压力都可以改善燃料电池的性能。第二部分利用有限元分析软件FEMLAB对燃料电池进行稳态数值模拟。基于质量、动量和能量平衡并耦合流体流动、热量产生和传递以及电化学知识建立了管型SOFC的CFD模型。模型中采用质量、动量、能量和组分守恒方程描述电池内的流动、传热传质等物理过程,并研究了电池内部的温度、浓度、气体流速及电流密度的分布情况。结果表明增大空气的流速则可以有效地降低电池内部温度,使电池内的温度分布更为均匀。第三部分以MATLAB/Simulink为平台,将燃料电池的CFD模型和燃料电池/微型燃气轮机混合发电系统的过程模型集成进行协同仿真,建立SOFC-MGT联合循环发电系统的数学模型并对其动态特性进行初步的仿真研究。更多还原

【Abstract】 Fuel cell (FC) is a new energy conversion device featuring high efficiency and low pollution. Because its electrical efficiency can achieve 50%-60%, the foreground is very good, the research and development of fuel cell have been emphasized in many countries now. The exit gas temperature of Solid oxide fuel cell (SOFC) is high, if a SOFC and microturbine are integrated into a hybrid system, it will achieve greater efficiency and effectively reduce the exhaust emission, decrease the pollution. Therefore, the performance analysis of the hybrid system is significative to our society.Because SOFC operating in high temperature, close and complex conditions, it is difficult to survey. The cost of the experiment is very expensive, sometimes it is impossible. So this thesis establishing the mathematics model of the hybrid system and analyze the performance in order to ensure that it’ll operate safely.This thesis includes there sections. In the first section, the theory of a natural gas-fed, tubular SOFC stack with internal reformer is analyzed. The calculation and analysis of the effects of the system parameter (current density, operating temperature, pressure, fuel flow-rate) on the cell performance (electrical power, electrical efficiency) is performed. Results show increasing operating temperature and pressure can improve the performance of SOFC. In the second section, the steady-state model of the Tubular SOFC is computed with a commercial Finite Element modeling package, FEMLAB. A CFD model for a tubular SOFC base on mass, momentum and energy balance coupled with fluid flow, heat generation and transfer and electrochemistry is presented, the model describes the fluid flow, heat and mass transfer in the SOFC, and also investigates the profile of temperature, concentration, gas flow rate and current density in the SOFC. Results show that increasing air flow-rate could decrease the SOFC temperature. In the last section, establishing the mathematic model of a SOFC-MGT hybrid system based on MATLAB/Simulink and integrates the CFD model of the SOFC with the process model of the microturbine to prosecute coordinated simulation, and analyzes the dynamic characteristic of the system.更多还原