钢烟囱的横风共振和空气动力稳定性设计研究

Study of across-wind resonance and aerodynamic stability of steel chimney

电力工程中,钢烟囱薄壁壳体的横风共振和空气动力失稳分析是一个十分复杂的问题.根据气动力平衡方程,结合空气动力阻尼和结构阻尼的比较,说明了坡度较小的烟囱结构不会发生弯曲驰振;另外,通过对烟囱壳体的动力特性以及烟囱不同高度处空气旋涡脱落频率的研究,说明了风力等级的不同对横风共振发生的区段具有明显的影响;最后通过数值方法研究了钢烟囱壳体的稳定性,结果表明烟囱壳体对于缺陷具有较强的敏感性,风压和工作负压作用下的钢烟囱锥壳的环向稳定性优于横风共振时壳体轴向的稳定性.上述结论对于薄壁钢烟囱结构的设计具有一定的理论意义和实用价值.

The analysis of stability and across-wind resonance of steel chimney in electric power engineering is a complex problem. In this paper, based the aerodynamics mathematic model, the comparison aerody- namic damping to structural damping is studied. It is clearly that galloping of steel chimney with small slope angle do not occurs. The analysis of dynamic characteristic and the frequency o{ the vortices are car- ried out. The speed of wind has great effect on the across-wind resonance. The buckling resistance of steel shell is studied through numerical analysis. The research shows that initial imperfection can reduce limit buckling stresses; and the axial buckling resistance under across-wind resonance is better than that in hoop direction under wind and gas pressure. The conclusions are helpful to the research on stability of thin- walled shells in both theoretical and practical significance.