电站锅炉过热器和再热器流量分布计算方法的改进

Improvement of the Calculation Methods for Flow Distribution in Utility Boiler's Superheater and Reheater

基于同屏支管根数、屏的节距和三通引入管对管组的流量分布有很大的影响 ,提出和实际结构相一致的离散模型计算方法 ,预测管组中的流量分布 .对进口三通涡流区对集箱静压分布的影响 ,给出了相应的实验结果 .以一台发生过超温爆管的锅炉再热器为例 ,分别应用离散模型计算方法和常用的连续模型计算方法 ,对管组的流量分布和炉内管壁温度进行了计算 .结果表明 ,离散模型计算方法的预测结果和实际情况相一致 。

The prediction of flow distribution in manifolds is important in the design of utility boiler's superheater and reheater. The branch tube number at a cross section of the header, the pitch between tube panels and T junction inlet pipe are the great influential factors on flow distribution in manifolds. The various continuous models available in the literature fail to predict satisfactorily the flow distribution in manifolds due to neglecting these influential factors, which often causes failure design. In this paper, a discrete model matching with the real physical phenomenon was proposed to predict the flow distribution in manifolds. The experimental evaluation of pressure distribution in the header near T junction inlet pipe was carried out to support the discrete model calculations. A boiler reheater in which overheating tube burst accident occurred was taken as an example. The flow distribution in manifolds and tube wall temperature inside the furnace were calculated by using the discrete model and a popular continuous model separately. The calculating results show that the prediction carried out by the discrete model coincides with the real conditions, and it improves the continuous model in which exists large calculation error.