Calculation of Leakage Rate for Bolted Flanged Joint During the Long Term Service at High Temperature

Abstract

Bolted flange joints (BFJs) are widely used in the process industries, and there is a large proportion served in the high temperature environment. During the long term service at high temperature, the creep relaxation of each component of BFJ will cause the decline of the residual gasket stress, which will further affect the sealing effect. So, it is very important to make sure the change rule of the leakage rate of BFJ during the long term service at high temperature. Firstly, according to constructing the relationship between the leakage rate and the service time, the leakage rate calculation method of BFJ during the long term service at high temperature was proposed. Secondly, the stress distributions of the gasket during the long term service at high temperature, which was time-dependent, were calculated at the tightness level T2 and T3 by using the numerical simulation method. Finally, based on the time-dependent average gasket stress and maximum gasket stress, the change rule of the time-dependent leakage rate of BFJ during the long term service at high temperature was obtained. The research results will play an important role in mastering the attenuation rule of the leakage rate of BFJ and supporting the leakage rate control of BFJ during the long term service at high temperature.