Numerical investigation on the effects of out-of-flatness on leakage in metal-to-metal seals

Abstract: Since the usage of pressurized systems, there has been a challenge to prevent and control leakage of different fluids. When a metal-to-metal face seal is designed, different aspects are to be considered. Its ring shaped sealing surface is designed to prevent leakage and also to maintain pressure. In this thesis, the main objective is to study how out-of-flatness affects the leakage. This property of sealing interface can be described by different wave parameters and in this case, by means of modelling and numerical simulations. The best approach is the usage of Heterogeneous Multiscale Method (HMM). The data obtained by means of the two-scale stochastic model showed that the pressure amplitude is the most important parameter of the out-of-flatness. In same level of importance, comes the mean pressure even though it is not considered an out-of-flatness parameter. From the data obtained, a simple mathematical expression for leak rate was constructed that shows the effect of out-of-flatness.