余晓峰,詹旺宇,魏成国,等. LNG薄膜罐动压力分布规律[J]. 油气储运,2025,44(5):1−13.
引用本文: 余晓峰,詹旺宇,魏成国,等. LNG薄膜罐动压力分布规律[J]. 油气储运,2025,44(5):1−13.
YU Xiaofeng, ZHAN Wangyu, WEI Chengguo, et al. Study of dynamic pressure distribution on LNG membrane tank[J]. Oil & Gas Storage and Transportation, 2025, 44(5): 1−13.
Citation: YU Xiaofeng, ZHAN Wangyu, WEI Chengguo, et al. Study of dynamic pressure distribution on LNG membrane tank[J]. Oil & Gas Storage and Transportation, 2025, 44(5): 1−13.

LNG薄膜罐动压力分布规律

Study of dynamic pressure distribution on LNG membrane tank

  • 摘要:
    目的 LNG薄膜罐是未来LNG储罐的发展方向,地震作用下LNG液体所造成的对流及冲击作用直接作用在LNG薄膜罐外罐罐壁上,罐壁需承受常规LNG全容罐罐壁未承受的LNG液体动压力,因此亟需对LNG薄膜罐动压力分布规律开展研究。
    方法 采用数值模拟方法,使用ANSYS有限元分析软件分别对海南25×104 m3 LNG薄膜罐及龙口30×104 m3 LNG薄膜罐进行建模。对25×104 m3 LNG薄膜罐进行OBE及SSE地震波下的时程分析,通过对比模拟分析结果与经典Housner公式计算结果验证了数值模型的有效性与一致性。基于此,结合30×104 m3 LNG薄膜罐在OBE及SSE地震波下的时程分析结果得到了多种工况下的LNG薄膜罐动压力分布情况,最终拟合得到LNG薄膜罐动压力分布公式。
    结果 罐内LNG液体的动压力作用是导致罐壁加速度最大的原因,罐体承受最大加速度时刻即为储罐受力最不利时刻。分析LNG薄膜罐的受力情况可知:在相同水平角度不同水平高度下,提出的LNG薄膜罐动压力分布公式与数值模拟结果及Housner公式结果曲线趋势一致,且各点数值与数值模拟结果相差均小于20%,特别是在低水平高度下该公式相比Housner公式考虑了罐壁与承台刚性连接处的刚度影响更加贴合数值模拟结果。相同水平高度不同水平角度工况下的对比结果同样验证了该公式的准确性。
    结论 提出的LNG薄膜罐动压力分布公式能较好地计算LNG薄膜罐在地震作用下承受的液体动压力,在保证混凝土罐壁具有足够承载力的前提下能显著降低设计中的保守度,对提高LNG薄膜罐混凝土外罐设计的经济性具有借鉴作用。未来将对实际大型LNG薄膜罐在地震条件下的动压力分布进行监测或开展缩尺模型实验,以期得到动压力分布数据,进一步提升该公式的适应性与准确性。

     

    Abstract:
    Objective LNG membrane tanks represent a future trend in the development of LNG storage tanks. Under seismic actions, the convection and impact of LNG liquid subject these tanks to dynamic pressure that directly applies to the walls of their outer containers—an effect not experienced by conventional LNG full containment tanks. Consequently, it is essential to investigate the distribution patterns of dynamic pressure on LNG membrane tanks.
    Methods A numerical simulation method, utilizing the finite element analysis software ANSYS, was employed to model the Hainan and Longkou LNG membrane tanks, with respective capacities of 25×104 m3 and 30×104 m3. Time-history analyses were performed on the 25×104 m3 tank under two seismic conditions: Operating Basis Earthquake (OBE) and Safe Shutdown Earthquake (SSE). The results from the simulation were compared to the calculations based on the classical Housner formula to verify the validity and consistency of the numerical model. Building on this, the dynamic pressure distribution on LNG membrane tanks was analyzed under various conditions, considering the time-history analysis results of the 30×104 m3 tank also subjected to seismic waves during both OBE and SSE conditions. Ultimately, a dynamic pressure distribution formula for LNG membrane tanks was derived through a fitting process.
    Results The dynamic pressure of LNG liquid within the tanks was identified as the primary contributor to the maximum acceleration of the tank wall, which occurs when the tanks experience the most unfavorable forces. By analyzing the force conditions of LNG membrane tanks, it can be concluded that: Under the same horizontal angle but at different levels, the proposed dynamic pressure distribution formula for LNG membrane tanks produced results that followed curve trends consistent with numerical simulation results and calculations based on the Housner formula. Specifically, values derived from the proposed formula at each point showed discrepancies of less than 20%when compared to the numerical simulation results. Notably, at lower levels, the results from the proposed formula aligned more closely with the numerical simulations than those obtained from the Housner formula. This closer alignment is attributed to the inclusion of the stiffness effect at the rigid connection between the tank wall and the pile cap. The accuracy of the formula was further validated through comparisons under various horizontal angles at the same level.
    Conclusion The proposed dynamic pressure distribution formula for LNG membrane tanks enhances the accuracy of calculating the liquid dynamic pressure experienced by these tanks during seismic actions. This improvement can substantially reduce the conservatism in design while ensuring adequate bearing capacity in the concrete tank wall, thereby illustrating a method to enhance the economic efficiency of the concrete outer container design for LNG membrane tanks. Future studies are anticipated to gather dynamic pressure distribution data that will further refine the adaptability and accuracy of this formula, either through monitoring the dynamic pressure distribution of large-scale LNG membrane tanks in actual applications under seismic conditions or by conducting scale-down model experiments.

     

/

返回文章
返回