Cavitation failure analysis of 90-degree elbow of mixing point in ethylene glycol recovery and concentration system

Abstract For the failure case of the 90-degree elbow of mixing point in the ethylene glycol recovery and concentration system of a refining and chemical company in China, the surface morphology of different cavitation degree was observed by scanning electron microscope(SEM). The composition and content of chemical material and working condition was calculated and analyzed by Aspen technical process simulation software to draw the conclusion that the failure form of elbow is cavitation of liquid water. The failure location of elbow was investigated by CFD numerical simulation used the VOF multiphase flow model and Schnerr and Sauer cavitation model. The distribution and variation of gas phase fraction is used to describe the cavitation dynamic development process at different times. The cavitation corrosion angle of elbow in the axial and circumferential direction was determined by the value of phase transformation rate, actual cavitation failure angle in the circumferential direction is basically consistent with that of numerical simulation, which verifies the reliability of the characterization method to a certain extent. The cause of the angle deviation between actual and simulation in the axial direction is explained. This paper can provide some reference for using phase transformation rate to predict cavitation location and characterize cavitation intensity.