摘要
准确计算电站锅炉水动力特性对发电系统的安全运行至关重要。本次研究旨在通过改进摩擦阻力压降的计算方法以优化水动力特性计算模型,提高电站锅炉受热面管内工质流动特性的计算准确性。通过将单管离散化为多个管段,并结合传热模型、压降模型以及水的物性模型,建立了水动力特性计算模型,在此基础上,将模型中的摩擦阻力系数视为变量,通过受热面进出口压力实测数据自动求解该变量,使模型可以依据实际运行参数对摩擦阻力系数进行自动修正。选取了一台超临界锅炉的水冷壁系统作为测试对象,在所测试的工况下,该模型得到的出口压降偏差和温度偏差分别控制在0.001 MPa和0.2℃以内。与传统的定摩擦阻力系数模型相比,该模型的出口压力偏差和温度偏差平均减少了0.204 MPa和1.4℃。计算结果显示,随着工作压力的降低,摩擦阻力系数呈现下降趋势,水冷壁摩擦压降和重位压降均减小,但摩擦压降的减小速率更大,导致重位压降逐渐取代摩擦压降的主导地位。此外,模型所计算的工质压力和温度变化曲线也与理论分析结果相符。研究表明,通过自适应摩擦阻力系数优化水动力特性计算模型,可以显著提高水动力特性的计算准确性,具有良好的应用价值。
The precise calculation of hydrodynamic characteristics of power plant boiler is of great importance for ensuring the safe operation of power generation system.This study aims to optimize the hydrodynamic characteristics calculation model by improving the calculation method for pressure drop due to frictional resistance,thereby enhancing the calculation accuracy of the fluid flow characteristics within the heating surface tubes of the boiler.A hydrodynamic characteristic calculation model is established in this study by discretizing the single tube into multiple tube segments and combining various models such as the heat transfer model,pressure drop model,as well as the water physical property model.On this basis,the friction drag coefficient in this model is regarded as a variable,rather than a constant.The model is optimized by employing a method that automatically solving this variable based on the measured data of the inlet and outlet pressure of the heating surface.This adjustment enables the model to self-correct the friction drag coefficient in accordance with the actual operational parameters.The adaptation of the friction resistance coefficient is realized through this method.For validation purposes,the water-cooled wall system of a supercritical boiler is selected as the test object.Under the test conditions,the deviation of outlet pressure drop and temperature obtained by the model are maintained within very tight tolerances of 0.001 MPa and 0.2℃,respectively.When compared to traditional models that utilize a constant friction coefficient,the outlet pressure deviation and temperature deviation of this model are reduced by 0.204 MPa and 1.4℃on average.The results indicate that as the working pressure decreases,the frictional resistance coefficient exhibits a downward trend,with both the friction pressure drop and the gravitational pressure drop within the water-cooled wall reducing.However,the rate of decrease in the friction pressure drop is greater,leading to the gravitational pressure drop gradually taking over the dominant position from the friction pressure drop.In addition,the curves of working medium pressure and temperature calculated by the model are consistent with the theoretical analysis results.This study demonstrates that optimizing the hydrodynamic characteristic calculation model through an adaptive frictional resistance coefficient can significantly improve the accuracy of hydrodynamic characteristic calculations,presenting well application value.
作者
汪艳华
李瑞宇
杨景泉
江志铭
杨家辉
WANG Yanhua;LI Ruiyu;YANG Jingquan;JIANG Zhiming;YANG Jiahui(Shunde Institute of Inspection,Guangdong Institute of Special Equipment Inspection and Research,Foshan 528300,China;State Key Laboratory of Multiphase Flow in Power Engineering,School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
出处
《甘肃科学学报》
2025年第6期121-127,共7页
Journal of Gansu Sciences
基金
广东省市场监督管理局科技项目(2024CT12)。
关键词
锅炉
水动力特性
摩擦阻力系数
数学模型
Boiler
Hydrodynamic characteristic
Friction drag coefficient
Mathematical model
