Experimental and numerical analysis of transient thermal stresses on thick-walled cylinder

Abstract

Thermal loading can be a significant source of stress, especially on pipelines, ducts, pressure vessels, and heat exchangers widely used in industry. Analytical and numerical studies of thermal stresses resulting from transient loads are restricted to simple geometries and simplified boundary conditions. Therefore, experimental data to confront these models are a necessity, particularly when analytical solutions are not available. This study aims at providing a mathematical model based on finite difference method to predict transient thermal stresses across a cylinder. To validate the model, experiments with strain gauges on the outer surface of a thick-walled cylinder were performed in a rig with controlled convective boundary conditions. Additionally, a numerical model based on Finite Element Method (FEM) was adjusted to reproduce the experimental and modeling results. Thermal stress evaluation occurs with temperature differences between the heat sink and source up to 70 °C, typical processing conditions of the oil and gas industry. Stresses are significant particularly during the startup and interruption of the production process. Peak thermal stress scales with mechanical stresses created by pressure difference of about 1050 bar. The agreement between experimental, finite difference method and numerical results paves the way to assess thermal processing equipment with complex geometry and boundary conditions.