Research On The Sealing Performance Of The Bolted Flange Joints Under The Dynamic Loads

In the petrochemical, nuclear and related industries, the sealing performance of bolted flange joint has an directly influence on the long-cycle operation of certain device. Particularly in the strong vibration conditions, the possibility of leakage due to the gasket sealing failure also grows, so the research on sealing performance of BFJ under dynamic loading conditions is crucial.In both process equipment and piping, BFJ is the most important form of connection, the connection structure under the operating conditions is affected by several factors, such as vibration environment, media pressure, and additional loads. These factors will cause the change of parameters related to the sealing performance, and the leakage are the main phenomenon causing by the change of parameters. Under dynamic load, the stress on gasket drop, eventually undermining the sealing performance. Therefore,Studying on the relationship between the sealing performance of flange joints and dynamic load is of great importance.In this paper, the pipeline system of floating BFJ is the research object. Base on the sealing theory of gasket, ensure tightness and structural integrity of BFJ, ANSYS has been leveraged to conduct the modal analysis and spectral analysis. Also vibration analyser and vibration table have been used to conduct experimental analysis. Finally determine relationship among system sealing performance with structure itself and seismic excitation.The results showed that, as the increase of pipe length, the stress on flange has a trend of decreasing, while the change of maximum stress on bolts is obvious. With the increase of the seismic intensity, the flange deflection angle changes more obvious. According to the results of vibration experiments showed that bolts strain and acceleration pipe changes appear to be highly correlated. Therefore, the failure of flange sealing performance is often not due to the strength of flange loss, what really need an enhancement is the strength of bolt, also the unacceptable deflection angle of flange is a causing factor of sealing failure. Under the vibration conditions, pipeline acceleration changes can be characterised by the changes of flange sealing performance indirectly, providing certain basis for online monitoring on sealing performance in special conditions.