论文部分内容阅读
管流与明渠流同属流体力学中的内流,其总流机械能方程在水力学中称为总流能量方程。现有水力学中的总流能量方程是以理想不可压缩液体的伯努利方程为基础得到的,无法得到总流机械能损失的表达式。该文作者曾直接从黏性不可压缩流体运动的控制方程出发分别得到了管流及明渠流的总流机械能方程,解决了以上问题。考虑到层流条件下明渠流自由表面的变形特点,该文在前述工作基础上,将管流及明渠流在层流条件下的总流机械能方程进行了统一,同时还分别计算了管流(圆管、不同长短半轴比的椭圆管、不同宽高比的矩形管和不同内外径比圆环管)及明渠流(不同宽深比的矩形明渠)在层流条件下的总流机械能损失系数。结果表明:在同一雷诺数条件下,圆管层流的总流机械能损失系数比椭圆管层流、矩形管层流、圆环管层流及较大宽深比的矩形明渠层流的机械能损失系数要小。
Both pipe flow and open channel flow belong to the influx of fluid mechanics, and its total flow mechanical energy equation is called the total flow energy equation in hydraulics. The total flow energy equation in the existing hydraulics is based on the Bernoulli equation of an ideal incompressible liquid, and the expression of the total loss of flow mechanics can not be obtained. The authors have obtained the total flow mechanical energy equations of the pipe flow and the open channel flow directly from the governing equation of the viscous incompressible fluid flow, and solved the above problems. Considering the deformation characteristics of the free surface of open channel flow under laminar flow conditions, based on the above work, unified the total flow mechanical energy equations of the pipe flow and open channel flow under the condition of laminar flow, meanwhile, Circular tube, elliptical tube with different ratio of length to short axis, rectangular tube with different aspect ratio and different inner-outer diameter ratio circular tube) and open channel flow (rectangular open channel with different aspect ratio) under laminar flow condition coefficient. The results show that under the same Reynolds number condition, the total mechanical loss of laminar laminar laminar flow is lower than that of rectangular laminar laminar laminar flow, rectangular laminar laminar flow, circular laminar laminar flow and large width-to-deep ratio open channel laminar flow The coefficient is smaller.