离心力作用下螺旋槽干气密封环强度分析

Strength Analysis of Spiral Groove Dry Gas Seal Ring under Centrifugal Force

高速下运行的螺旋槽干气密封,存在较大的离心力作用,由碳化硅等脆性材料制成的旋转环可能破裂,造成密封失效,甚至危害到主机。基于弹性力学理论方法和数值模拟方法,考察旋转密封环在离心力作用下的应力分布,并给出具体的案例。结果表明:数值分析方法与弹性力学理论方法得到的结果接近;旋转环径向应力随着半径的增大,呈先增大后减小的趋势,而切向应力在内径处最大,随半径增加而减小;径向和切向应力均随着角速度的增加而增大;由于切向应力远大于径向应力,强度校核时主要针对切向应力;当切向最大应力超过其强度极限时,认为密封旋转环即产生裂纹或断裂,从而失效。

When the spiral groove dry gas seal operates under high speed, the rotary ring which is made of SiC or other hard brittle materials may crack or break under the action of centrifugal force, which may lead to seal failure, even harm to the master machine.Based on the methods of elastic mechanics theory and numerical simulation, the stress distribution of rotary ring under the centrifugal force was investigated, and some specific cases were given.The results show that the stresses calculated by numerical analysis methods are very close to that calculated by elastic mechanics theory method.The radial stress of rotary ring is increased at first then decreased with the radius increasing, while the tangential stress is decreased with the radius increasing, and the maximum tangential stress is at the inner diameter.Both the radial stress and the tangential stress are increased rapidly with the increasing of angular velocity.The tangential stress is far greater than the radial stress,so the tangential stress is mainly checked when checking the operation security of rotary ring.When the maximum tangential stress exceeds its allowable strength, rotary ring may crack or break ,leading to the seal failure.