Analysis of the Effects of Pipe Specifications on the Critical Flow Velocity of Fluid

Abstract

This study applied the finite element method to analyse the internal flow induced vibration in a pinned-pinned pipe, while
studying the effects of increasing the length of the pipe span and the pipe bore diameter, on the critical flow velocity. The pipe is
undamped, and of rigid polyvinylchloride material. However, the fluid-pipe system experiences a gyroscopic damping arising
from Coriolis force. The analysis was carried out on pipe span lengths of 2m, 3m, 4m, 5m, and 6m, with corresponding 20, 24,
30, 42, and 50 elements respectively. Further analysed was the 2m pipe span length with the following respective bore diameters:
0.0389m, 0.0570m, 0.0697m, 0.0856m, 0.111m. All pipes maintained a uniform thickness of 0.00165m. The fluid is water, an
incompressible, non-volatile fluid, flowing at room temperature. The results are shown by graphical plots. For the 2m, 3m, 4m,
5m, and 6m pipes span lengths, the values of critical velocity obtained were 17.80 m/s , 10.00 m/s, 7.80 m/s, 6.20 m/s, and 5.90
m/s respectively, while 2m length pipes of bore diameters, 0.0389m, 0.0570m, 0.0697m, 0.0856m, and 0.111m each, produced
the following respective values of critical velocity, 17.80 m/s, 20.50 m/s, 22.50 m/s, 24.70 m/s, and 27.89 m/s. Generally, the
finite element method showed that critical velocity reduces with increasing pipe span length and increases with increasing pipe
bore diameter