电厂蒸汽回路系统中腐蚀损伤的决定论预测

局部腐蚀,包括点腐蚀、应力腐蚀开裂和腐蚀疲劳是导致电厂发电装置损伤的重要原因,它们诱发50%以上的意外停机事故。迄今,腐蚀破坏的预测一直沿用经验和统计的方法,但是,由于已证实该方法的适用性和其结果的准确性欠佳,故不宜作为例行检修规程的基础。本文提出了预测局部腐蚀损伤的决定论方法,并使用这个方法说明点腐蚀如何引发低压蒸汽轮机涡轮盘Wilson线下游部位的应力腐蚀开裂(SCC),我们的计算表明SCC的萌发与扩展对蒸汽小氧含量、冷凝液膜的环境和涡轮盘所承受的应力这三个因素敏感。

THE DETERMINISTIC PREDICTION OF DAMAGE IN POWER PLANT STEAM CYCLIC SYSTEMS

Localized corrosion phenomena,including pitting corrosoon,stress corrosion cracking,and and typically result in more than 50%of the unscheduled outages.Prediction of damage so that repairs and Inspections can be made during scheduled outages,could have an enormous impact on the economics ofelectric power generation,To date,prediction of corrosin damage has been made on the basis of empirical/statistical methods that have proven to be insufficiently robust and accurate to form the basis for the desired insion damgae.We have used the method to illustrate how pitting corrosion initiates stress corrosion cracking(SCC)for low pressure steam turbine disks downstream of the Wilson line,where a thin condensed liquid layer exists on the steel disk surfaces.Our calculations show that the SCC initiation and propagation are sensithat the disk experiences in service.