Numerical and experimental investigation on turbulent flow and secondary flow in a 180° bend -- Circular Cross-section

2018 International Conference on Civil and Hydraulic Engineering

土木建筑工程;水利工程

Shao, Qing^1,2 ; Hui, Weihua^1 ; Bao, Futing^1

College of Astronautics, Northwestern Polytechnical University, Xi'an

710072, China^1

Shanghai Electro-Mechanical Engineering Institute, Shanghai

201109, China^2

关键词: Centrifugal Forces;    Circular cross-sections;    Experimental investigations;    FLUENT software;    Laser Doppler Velocimetry;    Reynolds stress models;    Tangential velocities;    Turbulent models;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/189/2/022061/pdf
DOI  :  10.1088/1755-1315/189/2/022061

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

The characteristic of turbulent flow-filed in the circular-sectioned 180° bend was investigated in this study, the profiles of tangential velocity and pressure were measured by Laser-Doppler Velocimetry (LDV) and were simulated by FLUENT software. Different turbulent models are considered, including k-, RNG k- and Reynolds stress model (RSM) model. Compared with experimental measurements, the Reynolds stress model was selected to simulate turbulent flow in the bend. The results suggest that centrifugal force of fluid rotating contributes to the variation of tangential velocity and pressure in the bend. Secondary flow generating from the uneven pressure distribution in the bend was predicted by numerical simulation. Secondary flow generates near to the outer wall and shows great significance at 180° position. The secondary flow vortices moves from outer wall to inner wall gradually. This investigation indicates that turbulent flow-filed characteristics in the 180°bend can be understood in details by combined experiment measurement and numerical simulation.