48 / 2019-08-26 19:01:24

Vibration mechanism of clamped-spring cantilever pipe conveying two-phase flow

two phase flow, inclined pipe, virbation

In the present work, we have studied two-phase flow excitation mechanisms on forces and vibrations of clamped-spring cantilever pipe under the gravity effect. A phase-field approach with the Cahn-Hillard model is used to model the two-phase
interface while a cantilever beam model with spring support is
adopted to model the vibration response of the pipe. A two-dimensional channel geometry is considered.
For a horizontal pipe, if it is conveying with single-phase fluid, it can only subject to negative vibration response under its own weight. When the heavy fluid is injected as the top layer, the flow will become unstable jet and shed along the pipe interior, breaking the equilibrium zero position of pipe motion.
When the pipe is inclined, due to the generation of the oscillating jet and their interactions with the rolling waves, the pipe will be subjected to the combined first/second eigenmodes if the spring support is intensively clamped,e.g the spring stiffness $K\geq 15$ in the current study. On the other hand, when the heavy fluid is injected as the top layer, the flow regimes will be dominated by the unstable liquid slug and rolling waves, exciting the first eigenmode of the pipe motion.
Essentially, the fee-motion of pipe can interact with two-phase flow transitions inside the pipe, inducing various force distribution with distinctive features, which has determined vibration response of pipe with special characteristics.