摘要
以水蒸气空气混合物为例,利用努谢尔特修正膜模型和传热传质比拟原理通过简单迭代,得到混合气体水平管外凝结换热的一种总平均传热系数和平均气膜厚度的计算模型。在已知初始条件下,计算得到总传热系数随不凝结气浓度、主流流速及壁温的变化规律,并与已有计算式进行了比较,验证了结果的正确性。该计算模型适用于不同混合气体种类及不同表面形状。
Regarding steam-air mixture as example,using the Nusselt’s modified film model and the heat and mass transfer theory,gets a kind of the total mean heat transfer coefficient calculation model of mixed gas’s condensation heat transfer outside a horizontal tube and the mean gas film thickness by the simple iterative method.In the initial conditions known,the total heat transfer coefficient’s rules of changing with non-condensate gas’s concentration,mainstream flow velocity and wall temperature were obtained.Compared with the existing formula,the correctness of it’s results has been verified.The calculation model is suitable for different kinds of mixed gas and different surface shapes.
出处
《工业加热》
CAS
2012年第6期37-40,共4页
Industrial Heating
关键词
水平管
混合气体
平均传热系数
凝结换热
horizontal tube
mixed gas
the mean heat transfer coefficient
condensation heat transfer
