The failure causes analysis of low-pressure heater pipes based on the porous medium model and local model.

[Display omitted] • Combining global simplified and local turbulence models to calculate flow details. • Analysis of the low-pressure heater pipe failure causes. • Simulate the low-pressure heater with the porous medium model. • Obtained flow information in the damaged local area. Low-pressure heaters are critical heat exchange equipment in thermal and nuclear power generation. The high-speed steam flow in the low-pressure heaters induces pipe vibration, causing pipe failure. The large size and complex flow make it hard to calculate directly. This paper employs a combined method of the porous medium and local models by substituting the boundary to calculate and prove steam flow trajectory and velocity are consistent with the actual situation. The analysis of the turbulent kinetic energy exhibits that the primary causes of pipe vibration are the periodic vortex shedding and the impact of the impingement plate on the pipes. The stress analysis indicates that the loosening of the pipes leads to a 368 times amplification of the shear stress by 0.1 MPa. The most crucial step in solving such a problem is to strengthen the fixation of the pipes, especially near the shell region. [ABSTRACT FROM AUTHOR]