受热状态下水带内气泡核化特性研究

Characteristics of Bubble Nucleation in Fire Hose

消防水带在火场内长距离供水时,易受到火场高温的影响,在水带壁面形成气泡核化现象,导致水带内气液两相流动现象的发生,造成水带磨损和水枪的难以掌控,影响灭火救援。针对核化特性对基本方程进行了相应描述,着重阐述了均质核化与非均质核化的特点;并对气泡核化所需过热度进行了推导。分析了成核过程中气泡的受力状况,在进行合理化假设的基础上,求得气泡脱离直径;并提出了通过加权的方法。计算对流换热与汽化潜热在气泡核化过程中所占的比重,利用数学分析的方法,推导了总热流密度的计算式;并将数值解与实验数据进行了对比分析,提出了气泡核化特性与气泡脱离直径和气泡成核频率相关的指数有关。

In long distance water supply,fire hose may be affected by high temperture easily.This always leads to the formation of bubble nucleation on the hose wall,causing irTegular vibration.Fundamental equations are described,focusing on the characteristics of homogeneous nucleation and heterogeneous nucleation.The bubble nucleation in stress condition is analysed.Based on reasonable assumptions,gets the bubble detachment diameter,and the put forward the weighted method to calculate of convective heat transfer and latent heat of vaporization for bubble nucleation process.The mathematical solutions are compared with experimental data,the characteristics of bubble nucleation is related to bubble departure diameter and bubble nucleation frequency.