Study on Tube Profile and Heat Transfer Characteristics Under Flying-Ash Erosion

Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, 210096 Nanjing, China

^* Corresponding author: fqsi@seu.edu.cn

Abstract

Flying-ash erosion is the prime reason of the tube failure, involving the economy and safety of coal-fired power plants. To address this issue, computational fluid dynamics (CFD) is applied to this paper, which is coupled with the erosion profile calculation based on the dynamic mesh. The tube profile is analyzed under the flying-ash erosion, and the heat transfer process is further taken into account. The results indicate that as time goes on, the impact frequency and the incident angle decrease at the lower angle and increase at the higher angle. With time going on, the peak value becomes smaller at the saddle-shaped erosion rate curve, and the position of the peak value moves towards the higher angle. Meanwhile, both sides of the saddle-shaped curve expand towards the higher angle. That is, the erosion rate and the erosion loss become higher. The Nusselt number grows slightly and the trend grows faster as time goes on. The erosion profile leads to raising the temperature gradient at the angle of 0°, which induces the tube to rupture ultimately.