Experimental and numerical investigation of erosion behavior in 90° elbows of heat-exchanger tubes

Erosion in elbows is a critical factor affecting the safety and service life of heat-exchange pipelines. To elucidate the erosion patterns of 90° elbows in heat-exchanger tubes under solid–liquid two-phase flow, this study conducts a systematic investigation combining experimental measurements with numerical simulations. An erosion test rig was first designed and constructed, and specimens were arranged at different positions on the inner wall of the elbow to investigate the effects of flow velocity, particle diameter, erosion duration, and specimen orientation on the erosion rate. These tests identified the primary influencing factors and their roles. Due to experimental limitations in capturing minor erosion and evaluating structural parameters, a Fluent-EDEM coupled model based on the Eulerian-Lagrangian approach was further established to simulate the erosion characteristics in the elbow. The numerical results were validated against experimental data, demonstrating the reliability of the model. The simulations provide flow-field and erosion information difficult to obtain experimentally and systematically reveal the effects of flow velocity, particle properties, and geometric parameters on erosion distribution and local erosion intensity. This study enhances the understanding of elbow erosion mechanisms and offers a theoretical basis for the structural optimization of heat-exchange tubes under particle-laden flow conditions.