Stress Analysis and Sealing Performance Evaluation of Pipe Flange Connection at Elevated Temperature Available to Purchase

Although a lot of pipe flange connections are exposed to elevated temperature during plant operation, a sealing performance of the pipe flange connections at elevated temperature is not well understood because of the experimental difficulty and the analytical problems due to the lack of the materials properties of gaskets at elevated temperature. The authors have been evaluating the sealing performance of the pipe flange connections at elevated temperature with numerical and experimental analysis and showed the strong effect of the material properties of the gaskets, like a thermal expansion coefficient and a stress-strain curve, on the sealing performance. In order to make a further evaluation, the effect of material properties on the sealing performance was analyzed by using FEM. In the FE analysis, the material properties were varied to evaluate the effect of them on the sealing performance. Furthermore, the material properties and the mechanical characteristic of the gasket were evaluated as a function of temperature. The obtained properties were used to reanalyze the sealing performance of the pipe flange connection. As a result, the gasket stress induced by the mismatch of the thermal expansion between the gasket and flange/bolt increased as increasing the temperature in the case that the thermal expansion coefficient of the gasket was larger than that of bolt/flange material and the sealing performance of the pipe flange connection was improved. However, the improvement in the sealing performance at elevated temperature was not expected so much at higher temperature due to the less increment of the thermal expansion and thermal stress of the gasket. This paper discuss about the change in the sealing performance of the pipe flange connection under elevated temperature considering the material properties and mechanical characteristics of the gasket.