Handling and utilization of steam flow efficiently to obtain various tangible industrial outcomes relies mainly upon how to optimize various flow parameters like boundary layer thickness, skewness, shear stress, and turbulent dissipation for minimum losses such as pressure and heat. Swirling steam flow, driven by a propeller through a circular duct along horizontal and inclined surfaces presents an interesting flow regime that includes the boundary layer flows close to the wall of the pipe and weak and uniform flow that prevails across the inner region of the pipe. Such flow was investigated here with a specially designed experimental facility. Convective Instabilities were observed that propagate along the axial direction in a nonlinear fashion. It was observed that the operating conditions could be optimized for measuring the shear stresses based on the intersection of the profiles under the effect of variations in the inlet pressure of steam and the rotational speed of the propeller. We found that the flow transformed from positive to negative skewness when the rotational speed of the propeller was raised from 4–14 thousand per minute at 10 bars of constant inlet steam pressure. More area came under the effect of reduced skin friction when the rotational speed of the propeller was raised. More turbulent energy was found to be dissipated when the rotational speed of the propeller was raised. It was found that yet the dissipation of the turbulent energy takes place under the joint effect of inlet pressure of steam and the rotational speed of the propeller, but the exact effect of any one of these two operating parameters still needs to be determined and requires further investigation.

中文翻译：

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水平段和倾斜段管道中涡流蒸汽流壁边界层内的流动特性

有效地处理和利用蒸汽流以获得各种有形的工业成果主要取决于如何优化各种流动参数，如边界层厚度、偏度、剪应力和湍流耗散，以最大限度地减少压力和热量等损失。螺旋桨驱动的旋流蒸汽流沿水平和倾斜表面通过圆形管道，呈现出一种有趣的流动状态，其中包括靠近管道壁的边界层流和遍布管道内部区域的弱且均匀的流动。这种流动在这里用专门设计的实验设施进行了研究。观察到以非线性方式沿轴向传播的对流不稳定性。据观察，在蒸汽入口压力和螺旋桨转速变化的影响下，可以优化操作条件以测量基于剖面交叉的剪切应力。我们发现，在 10 巴的恒定入口蒸汽压力下，当螺旋桨的转速从每分钟 4 到 14 千转时，流量从正偏度转变为负偏度。当螺旋桨的转速提高时，更多的面积受到减少的皮肤摩擦的影响。当螺旋桨的转速提高时，发现更多的湍流能量被消散。研究发现，在蒸汽入口压力和螺旋桨转速的共同作用下，湍流能量消散，