Numerical Simulation Analysis of Elbow Erosion in Underground Gas Storage Process System

Aiming at the erosion failure risk of key elbow components in the process system of underground gas storage (UGS), numerical simulation was adopted to investigate the erosion behavior and mechanism of elbows under the following three typical working conditions: gas injection, gas production, and wastewater treatment. The results show that the elbow in the gas injection system is under gas–solid two-phase flow, and the most severely eroded area is located at 45–50° on the outer arc side of the elbow. Small particles have stronger flow-following ability than large particles and collide with the wall more sufficiently, resulting in a higher erosion rate. For the tandem elbows in the gas production system, affected by centrifugal force and secondary flow, the outer arc side shows high pressure while the inner arc side shows low pressure. As the particle size increases, the erosion rates of both elbows decrease, with a larger reduction for the second elbow. The most severely eroded positions of the first and second elbows are at 50–55° and 40–45° on the outer arc side, respectively. The elbow in the wastewater treatment system has relatively slight erosion with a symmetrical distribution, but a small amount of natural gas accumulated on the inner side easily induces cavitation corrosion.