Erosion evaluation of elbows in series with different configurations

Abstract

Erosion of elbows in series has received more attention recently as many facilities have elbows in series with various orientations and installations. It has been observed from experiments that, for liquid-dominated flows when two elbows are placed in series and with a small distance between them, the maximum erosion takes place in the second elbow. However, it is also necessary to study the effect of the orientation of the elbows because in the oil and gas industry, for example, there are all types of combinations of elbows in series in the field. In this work, experiments were conducted in a 50.8 mm diameter experimental facility considering liquid-solid and liquid-gas-solid flows and one configuration of elbows in series: where the first elbow for both configurations is upward vertical-horizontal and the second elbow orientation is horizontal-vertical downward. Also, the distance between elbows was kept constant (being three diameters). Additionally, Computational Fluid Dynamics (CFD) studies were performed and compared with experiments. After validation and sensitivity studies concerning numerical solutions, a comprehensive numerical study was conducted, taking into account different scenarios regarding the orientation of elbows using three configurations of two elbows in series. The results show that the normal and the 180° configuration of two elbows in series are less sensitive to the gravity orientation for liquid-solid flows than the other two configurations investigated. On the other hand, for liquid-gas-solid flows, erosion changes with gravity orientation. The worst-case scenario for liquid-solid flow is suggested to be the 180° configuration, while for the liquid-gas-solid flow, the 90° configuration. Thus, it is important to understand the erosion behavior with the orientation of the elbows, because erosion can be reduced by changing the orientation or the configuration of elbows in series.