Practical guidelines to mitigate flow induced failures
Proceedings Publication Date
Gas under high pressure and with high velocity contains a serious amount of kinetic energy. This kinetic energy is the main condition for the appearance of vibrations and therefore a risk for vibration induced fatigue failures. In general, lower gas velocities will lead to lower integrity risks but there are exceptions, as will be presented. The impact of high gas velocities on the integrity of gas pipeline systems will be shown with failure statistics and failure examples, like fatigue and erosion. Circumstances that have led to these real failure cases will be elaborated and root causes will be discussed. Following the failure cases, the background of the impact of high gas velocities will be addressed, with special attention to the occurrence of flow induced pulsations and vibration induced fatigue failures. The physical phenomena leading to flow induced pulsations and vibrations will be visualized and described in a very practical way, with examples. Attention will be given to relevant codes and practices. Potential additional effects of pulsations, like misreading’s, flow resistance and noise, will be stipulated. Based on the above, practical solutions and mitigating measures will be indicated. In this paper, the reader will gain practical understanding of the mechanism behind flow induced vibrations. It will concentrate on transfer of practical understanding of and practical guidelines for the avoidance of flow induced problems and especially fatigue failures. It will be useful for facility managers, operators, designers, and engineers when they need to identify and or to avoid catastrophic instances of vibration-induced fatigue failures in their gas pipeline system, both pipelines and facilities.