焊接金属波纹管机械密封端面径向振动特性研究

Research on Radial Vibration Characteristics of Mechanical Seals of Welded Metal Bellows

焊接金属波纹管机械密封是轴类密封的重要类型之一,而密封端面振动特性是泄漏量和端面磨损的关键影响因素。由于目前针对焊接金属波纹管机械密封端面振动位移相关理论研究较少且没有具体分析各工作参数对端面振动的影响。首先,作者建立了端面密封环的几何模型和极坐标下端面所受表面压力以及分布力矩的数学模型;采用圆环理论和数值分析方法,推导出受谐波形式载荷条件下端面振动位移的求解公式。然后,利用MATLAB求解出密封端面在不同工况条件下轴向振动和径向振动位移特解。发现在相同的工况条件下径向振动位移均大于轴向振动位移。最后,设计了径向振动试验,利用电涡流传感器测量密封端面径向振动位移,分别探究了介质压力、工作转速、载荷系数和压缩量对径向振动位移的影响。结果表明:工作转速和压缩量对径向振动位移影响较大,介质压力和载荷系数对径向振动位移影响趋势相同。径向振动位移随着转速的增大而急剧增大;随着压缩量的增加先缓慢增大后迅速增大;随着介质压力的升高、载荷系数的增大,径向振动位移先减小后增大。对比理论计算和试验结果,验证了密封端面振动位移数学模型的正确性。优选出合理的工作参数范围为:介质压力为0.4～1.4 MPa,工作转速为1 500～2 500 r/min,载荷系数K为0.60～0.75,压缩量为4～6 mm。

The mechanical seal of welded metal bellows is one of the important sealing methods in shaft seal,and the vibration characteristics of seal end face are a key factor in the amount of leakage and end face wear.Due to the lack of the theoretical research on the vibration displacement of the mechanical seal face of welded metal bellows,the influence of each working parameter on the end face vibration has not been analyzed.The geometric model of the face seal ring and the mathematical model of surface pressure and distribution moment under the polar coordinate were established.Based on the ring theory and numerical analysis method,the solution formula of the end face vibration displacement was deduced.Then,the special solution of the axial vibration and radial vibration displacement under different working conditions of the sealing face was solved by using MATLAB.The comparison of the results of special solutions of displacemen showed that the radial vibration displacement is larger than the axial direction under the same working conditions.A vibration test was designed for the radial direction.The displacement of the seal face was measured by using eddy current sensor,and the effects of medium pressure,working speed,load coefficient and compression amount on radial vibration displacement were studied.Experimental results showed that the working speed and compression have a serious impact on the radial vibration displacement,and the medium pressure and load coefficient have the same influence trends on the radial vibration displacement.With the increase of the working speed,the radial vibration displacement drastically increases.As the amount of compression increases,it increases slowly and then increases rapidly.With the increase of the medium pressure or the increase of the load factor,the radial vibration displacement decreases first and then increases.By comparing theoretical calculations with experimental results,the correctness of the mathematical model of the vibration displacement of the seal face was verified.The reasonable working parameters are listed as follow:The medium pressure is 0.4~1.4 MPa,the working speed is 1 500~2 500 r/min,the load factor K is 0.60~0.75,and the compression is 4~6 mm.