Design of Bypass Structure and Dynamic Motion Simulation for Ultra-Large Diameter Pipeline Inspection Gauge

Abstract

Aiming at the problem of controlling the operating velocity of a large-diameter heavy-duty pipeline inspection gauge (PIG), this paper designs the bypass structure to study the velocity change and flow field state when the DN1219 mm PIG is operating in pipeline with different bypass rates. Fluent is applied to numerical simulation of the fluid-structure interaction flow field based on the dynamic mesh method. The results show that: the bypass rate of 2%–3% can satisfy the velocity of PIG in 3–5 m/s reasonable interval. The larger the bypass rate is, the larger the turbulence intensity is, and the gradual increase of the pressure difference suffered by the PIG. The operating velocity of the PIG can be regulated more accurately by corresponding to the bypass rate and the pressure difference front and rear. Comparing the experimental and simulation results, the error rate of the velocity decrease with bypass rate of 1%–3% is 12.8%.

Keywords: Bypass rate, Dynamic mesh, Pressure difference, Turbulence intensity, Fluid-structure interaction