Author(s)

Zhang Xiaojun, Yao Qiang, Miao Yang

Corresponding Author

Xiaojun Zhang

Abstract

The problem of local energy loss characteristic induced by the fluid pulsation with high Reynolds number in the U-bend pipe, numerical investigation of the fluid pulsation in the U-bend pipe with different deflector structures were presented with the help of the LES (large eddy simulation). Aimed at four different types of deflector structures, the pressure gradient, secondary flow, eddy and flow resistance were analyzed comparatively. The results show that the bend part in pipe induces the fluid pulsation, and the accelerated or decelerated motion of fluid particles induced by the pressure gradient results in the Dean eddy. During the fluid pulsation, the cores of high velocity eddy and low velocity eddy all draw close to the centerline of pipe, merge together, and form the core zone of steady jet flow. In order to determine the deflector structure, not only the local energy loss but also the flow resistance are need to be considered simultaneously, and the example of Case 4 is presented in this paper.

Keywords

U-bend, Deflector, Secondary Flow, Local Energy Loss.