变压运行超临界压力直流锅炉螺旋管圈水冷壁的技术特点分析

Technical Feature Analysis of Spirally-wound Tube Water Wall of Supercritical Pressure Once-through Boiler at Variable Pressure Operation

结合螺旋管圈和垂直管圈的特点,阐述了变压运行下超临界压力及超超临界压力直流锅炉水冷壁产生水动力不稳定和传热恶化的原因及其解决问题的方法。介绍了近几年在国产机组中出现的螺旋管圈水冷壁的结构,其基本型式是螺旋管圈与垂直管圈相结合,并分析了该结构型式的技术特点。认为采用螺旋管圈水冷壁可提高水动力稳定性、抗燃烧干扰能力和运行可靠性,能抑制传热恶化,尤其是内螺纹管的变压运行技术性能较优越,因此,螺旋管圈水冷壁必将成为超临界压力及超超临界压力直流锅炉水冷壁的主要结构型式。

Combined with the features of spirally-wound tubes and vertical tube coils, this paper expounds the causes and solution of fluid-flow instability and heat-transfer penalty of the water walls of supercritical pressure and ultra supercritical pressure once-through boilers at variable pressure operation. It also describes the structure of spirally-wound tube water wall adopted in domestic units in recent years, which combines spirally-wound tubes and vertical tube coils as its basic pattern, and analyzes the technical features of the structure. It is concluded that using spirally-wound tube water wall can improve the dynamic water stability, anti-combustion interference capability as well as operation reliability, restrain heat-transfer penalty, and is superior in the variable pressure operation performance due to the riffled tubes adopted. As a result, the structure of spirally-wound tube water wall is bound to prevail in supercritical pressure and ultra supercritical pressure oncethrough boilers.