天然气管道极限压力有限元模拟研究

管道极限压力的确定能为管道设计提供优化参数和安全运行保障,节约建设成本,降低危险系数.但现有预测公式往往偏差较大,导致浪费和评估误差.利用三维有限元模型,模拟天然气管道在不含裂纹、不同长度纵向穿透裂纹和环向穿透裂纹三种情况下的极限压力,并根据模拟结果建立两种含裂纹情况下极限压力与管道材料性能、尺寸、裂纹长度的工程预测模型.与已知预测模型比较发现,在无裂纹存在时,Christopher公式的预测公式可很好地用于工程分析,但在含缺陷情况下,现有预测公式与本文所建公式相比存在较大保守性,尤其对环向穿透裂纹存在时,已知预测模型与模拟结果存在极大差异.

Finite Element Analysis of Limit Pressure for Longitudinal Through-wall Cracked Natural Gas Pipeline

Limit pressure can provide pipeline design parameters and the guarantee of safely operating,thus sav-ing the construction cost and reducing danger of burst accidents. In this paper, three-dimension finite ele-ment is used to study the plastic limit pressures (Pm) of natural gas pipelines under three conditions:with-out defects,having longitudinal and circumferential through-wall cracks each. Based on the results of simu-lation,the corresponding predictive formulations of Pm to the material property, pipe dimension and crack length (or crack angle) are established. Compared with existing predictive models,it comes to these con-cludes as here:if there were no defects in the pipe,Christopher's model (formula 3) can be safely used. But to the conditions that through-wall cracks were included, the already known models would result higher discrepancy,especially for circumferential through wall cracked pipes.