摘要
以双端断裂后的高能管道为研究对象,对蒸汽射流过程进行了数值模拟.研究了滞止压力、管道壁面摩擦对喷射锥和射流冲击力的影响,总结了喷射锥内速度、温度、压力的规律.并将不同入口条件下的射流冲击力与使用设计准则计算结果进行了比较,探究了设计准则在超出适用压力范围时,有关公式和方法的适用性.模拟结果表明,蒸汽射流在出破口平面后一段距离内,压力和温度迅速下降,速度迅速上升,随后均有波动变化,最终随着逐渐远离喷嘴出口,速度、温度逐渐下降,压力趋近于大气压.喷射锥初始扩散角度、射流影响范围及射流冲击力与入口压力正相关,与喷管壁面粗糙度负相关.设计准则对射流初始扩散角度的假设不具有普遍性,当压力较大时,实际射流初始扩散角度大于规范规定的45°.设计准则评定冲击射流全部喷射到平板的冲击效应时,标准对于理想无摩擦的管道喷射冲击力可以精准预测,但使用标准对实际有壁面摩擦的管道射流冲击力进行评估时,会存在一定偏差,且随着壁面粗糙度和压力的增加,评估偏差程度会增大.
The steam jetting during the double-end fracture of high-energy pipelines was studied through numerical simulations.The effects of stagnation pressure and pipe wall friction on the jet cone and impingement forces were investigated,and the patterns of velocity,temperature,and pressure in the jet cone were summarized.Additionally,by comparison of the impingement forces under various inlet conditions with the results calculated based on the design criteria,the applicability of the design criteria beyond the applicable pressure range was studied.The results show that,the pressure and temperature of the steam jet decrease rapidly within a certain distance from the nozzle outlet,while the velocity rapidly increases,followed by fluctuations and changes.As the distance from the nozzle outlet increases,the velocity and temperature in the jet cone gradually decrease,and the pressure is close to the atmospheric pressure.The initial spread angle of the jet cone,the influence zone of the jet cone,and the impingement force are positively correlated with the inlet pressure,and negatively correlated with the roughness of the inner wall of the nozzle.The assumption of the initial jet cone angle in the design criteria is not universal,and the actual initial jet cone angle exceeds 45°set by the standard model at higher stagnation pressures.In the case where the whole jet impinges on the flat plate,according to the design criteria,the standard model can precisely predict the impingement force of the steam jet in the ideal pipe without wall friction.However,under the design criteria,there will be some deviation to evaluate the impingement force on a real pipe jet with wall friction,and this deviation will increase with wall friction and pressure.
作者
徐焱明
信志强
何铮
蔡煜
XU Yanming;XIN Zhiqiang;HE Zheng;CAI Yu(College of Mechanics and Engineering Science,Hohai University,Nanjing 210098,P.R.China;Chinergy Co.,Ltd.,Beijing 100193,P.R.China)
出处
《应用数学和力学》
北大核心
2025年第2期142-153,共12页
Applied Mathematics and Mechanics
基金
国家自然科学基金(11872174)。
关键词
高能管道
蒸汽射流
壁面摩擦
冲击力
high-energy pipeline
steam jet
wall friction
impingement force
