【作者】 郑璐；

【导师】 周克毅；

【作者基本信息】 东南大学 ， 热能工程， 2006， 硕士

【摘要】 锅炉是一种系统复杂、体积庞大和价格昂贵的能量转换设备,其中尤以锅炉蒸发区的特性最为复杂。蒸发区的特性对锅炉的运行控制方式以及控制参数的设定有着直接的影响。随着锅炉容量的不断增大和热力参数的继续提高,锅炉蒸发区特性对整个锅炉及发电机组安全性的影响也越显重要,这就对锅炉蒸发区特性的研究工作提出了更高要求。本文综合分析了汽包锅炉蒸发区的已有数学模型及建模方法,以巴威公司2000t/h亚临界自然循环锅炉为研究对象,用理论分析的方法建立了其蒸发区机理性数学模型。关于汽包虚假水位产生的分析,现有文献均认为是由于水下汽容积引起的。基于准动态计算分析和蒸发区完整模型的动态仿真试验,本文确定蒸发区循环管路贮质量变化也是引起虚假水位的重要影响因素。特别是在压力上升、水下汽容积变化不大的情况下,蒸发区循环管路贮质量变化的作用更是不可忽略的。针对以往利用静态曲线求取锅炉汽包水下汽容积的不合理问题,综合考虑了水下蒸汽容积产生和消逝的机理,建立了新的能反映水及金属热惯性影响的水下汽容积机理性计算模型。文中所建自然循环锅炉蒸发区模型较之一般模型可以更准确更有效地反映蒸发区动态特性,文中结论完善了锅炉汽包虚假水位现象的理论解释,对汽包锅炉的运行和控制有重要的指导意义。更多还原

【Abstract】 Boiler that has complex system, large cubage and highly cost is used to convert energy and the characteristic in the area of evaporation is especially complex. The characteristic in the area of evaporation has more direct effect to the running method of boiler and the setting of control parameter. The capacity of the boiler is continuously increased and the parameter of thermal dynamics is improved greatly. With it, the structure of boiler is more complex, and the management of the system becomes more strictly. This will bring forward more requirements to research the characteristics in the area of evaporation.This paper has concluded the method of how to establish a mathematical model and the development progress of this model, then used evaporation area in 2000t/h boiler systems which produced by B&W as a research object., established the dynamic mathematical model by theoretical analysis method.Some existing papers considered that the false water level is related to the steam-cubage in water. Based on standard dynamic analysis and the simulation of new water level model, this paper indicates that the changing mass storage in evaporation area is also an important factor of false water level. Especially when the pressure ascends and no steam-cubage exists in water, the changing mass storage is more prominent.Compared to other evaporation area models, this model could reflect dynamic characteristic more accurately and effectively. The conclusion is referable for the explanation of physical phenomena in evaporation area and for the designing and setting of the control systems.更多还原