A Study on the Instantaneous Turbulent Flow Field in a 90-Degree Elbow Pipe with Circular Section

Abstract

Based on the special application of 90-degree elbow pipe in the HTR-PM, the large eddy simulation was selected to calculate the instantaneous flow field in the 90-degree elbow pipe combining with the experimental results. The characteristics of the instantaneous turbulent flow field under the influence of flow separation and secondary flow were studied by analyzing the instantaneous pressure information at specific monitoring points and the instantaneous velocity field on the cross section of the elbow. The pattern and the intensity of the Dean vortex and the small scale eddies change over time and induce the asymmetry of the flow field. The turbulent disturbance upstream and the flow separation near the intrados couple with the vortexes of various scales. Energy is transferred from large scale eddies to small scale eddies and dissipated by the viscous stress in the end.

Study on Flow Field Characteristics of the 90° Rectangular Elbow in the Exhaust Hood of a Uniform Push–Pull Ventilation Device

“…When the curvature radius changed from R = 1 h to R = 4 h, the wind flows opposite to the mainstream wind traces continued to reduce until they disappeared, and the final wind traces were basically parallel lines. Wang et al studied the instantaneous turbulent flow field of a 90° elbow and their results are similar to the results shown in Figure 3 [26]. In some cases, because there are a large number of opposite wind traces in the vortex, which are inconsistent with the main flow direction, the ventilation effect is significantly reduced.…”

Influence of green inhibitor on flow-accelerated corrosion of API X70 line pipe steel in synthetic oilfield water

“…This is due to variations in hydrodynamic parameters such as wall shear stress and velocity at the elbow test section. Furthermore, the secondary flow and/or flow separation effect, which will lead to the generation of counterrotating vortexes, and various scale eddies at an elbow will disturb the flow pattern and promote the mass transfer process near the pipe wall [6,43,44]. The CFD simulation results discussed in the previous work was also indicated that the shear stress and velocity are different at various locations of the elbow test section [24].…”

SPH simulations of turbulent flow in curved pipes with different geometries. A comparison with experiments

“…In particular, they found that LES reproduced the experimental profiles for the streamwise mean velocity and turbulent intensity just behind the elbow much better than RANS, while inside the bend both approaches yielded comparatively similar mean velocity profiles and pressure coefficients. Further FVM-based calculations of turbulent flow in 90 • elbows were presented by Dutta et al [29] and Wang et al [30].…”