Case study: Erosion of an axial flow regulating valve in a solid-gas pipe flow

In some gas fields in southern China, axial flow regulating valves are often exposed to extreme conditions, where high speed flow (greater than 20m/s) and particle erosion (particle concentration of 1 mg/s–100  mg/s) lead to inner leakage and flow suppression. Surface erosion behavior is investigated through on-line particle monitoring experiments and 3D imaging wear measurements, and various flow control approaches are proposed to study the erosion characteristics of axial flow regulating valves. Numerical studies of Euler–Euler and Euler–Lagrange methods are introduced to provide a theoretical insight into the erosion caused by fine particles in the compressible flow. The erosion behavior characteristics are identified and further studied by applying a relatively large-scaled moving grid method. The results indicate that depending on the valve opening, the severely eroded area will shift from the edge of the extrusion to the center of the extrusion part. The Euler–Euler method combined with the Oka erosion model can provide a satisfactory result in a compressible gas flow laden with particles. The erosion rate presents a decreasing trend with increasing operation pressure due to the gas compressibility. The erosion rate, impact velocity, and impact angle present a decreasing trend with decreasing wall thickness of the valve core when the surface evolution is considered. The conventional transient calculation could only provide a satisfactory result in a limited time span, while calculations with a moving grid method show the erosion behavior of the total failure process along the valve's life span.