污垢效应对螺旋管式蒸汽发生器蒸干点影响分析研究

Study on the Dry-out Point of the Helical Tube Once-through Steam Generator Considering the Fouling Effect

螺旋管式蒸汽发生器(HOTSG,Helical coiled Once-Through Steam Generator)的蒸干点位置由于传热恶化会带来额外的风险,而工质中的腐蚀产物会沉积在传热管表面形成积垢影响螺旋管蒸干点的产生位置,本研究基于自主开发螺旋管模型的热工水力系统程序WISTARIA,分析了不同的积垢厚度对螺旋管式直流式蒸汽发生器传热管换热系数、含气率、蒸干点生成位置的影响程度。研究结果表明,螺旋管式直流蒸汽发生器积垢后,局部换热性能下降,进而影响压降与临界含气率,并影响蒸干点的液膜破碎过程。本研究结果为考虑积垢对螺旋管式直流式蒸汽发生器蒸干点的影响提供了设计参考依据。

The position of the dry out point(DO)of the helical tube steam generator will bring extra risk due to the deterioration of heat transfer,and the corrosion products of materials in secondary circuit will deposit on the surface for OTSG(once-through steam generator)and influence the heat transfer tube and form scale,which will affect the position of evaporation point of the helical tube.This study is based on the thermal hydraulic system program WISTARIA of the self-developed helical pipe model,the influence of fouling thickness on the heat transfer coefficient,void fraction and the position of evaporation point of the once-through spiral tube steam generator was analyzed.The results show that the local heat transfer performance of the once-through steam generator decreases after fouling,which affects the pressure drop and critical void fraction,and the fouling on the wall will affect the liquid film breakage process at the evaporation point.The results of this study provide a reference for design considering the influence of fouling on the evaporation point of the spiral tube once-through steam generator.