天然气管线全焊接锻造球阀最大弯曲载荷研究

Analysis of the Maximum Bending Load on Gas Pipeline All-welded Forging Ball Valves

为保证天然气长输管线全焊接锻造球阀在地基沉降、山体滑坡等实际可能工况下有足够强度和良好密封性能,基于有力矩理论和弯曲应力理论,从强度和密封角度对全焊接锻造球阀可承受最大弯曲载荷进行理论分析计算和数值模拟实验,得到全焊接锻造球阀同时满足强度与密封性能的最大弯曲载荷;通过分析理论载荷值与临界载荷值得到修正系数C,求出全焊接锻造球阀在任意公称压力和直径下可承受最大弯曲载荷.研究表明:在保证强度有效的最大弯曲载荷下,球阀密封性能依然有效;修正系数的引入弥补了理论计算无法考虑结构突变、应力集中、几何非线性等因素引起的不足;研究方法弥补了国内无法进行全焊接锻造球阀抗弯性能评估型式试验的不足.

To guarantee enough strength and good sealing performance of natural gas pipeline all- welded forging ball valve under the harsh working conditions such as foundation settlement and mountain landslide, based on the moment theory and the bend stress theory, the theoretical analysis and simulate numerical methods were used to achieve the maximum bending load that can fulfill strength and sealing demands simultaneously. Correction coefficient C was obtained through analyzing theoretical loads value and critical loads. Then, the ultimate bending load of series products with arbitrary nominal pressure and diameter were obtained. The results show： First, the sealing performance still works effectively under the maximum bending load which ensures strength; Second, the correction coefficient makes up for the weaknesses of theoretical calculation, which cannot consider structural mutation, stress concentration, geometric nonlinearity, et al; Third, the research methods make up the lack of that type test of pipeline ball valve flexural behavior evaluation is unable to proceed in China.