Abstract: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.