Experimental Study of the Flexibility of a Full-Scale Two-Dimensional Steam Pipeline

Abstract

This paper describes tests made to check the reliability of the calculation methods used to predict the flexibility, forces, and stresses in a typical pipework system.

A test rig set up in the laboratory has been used to carry out tests on a full-scale pipeline of 6 1/2-in. nominal bore pipe for 450 lb/in² working pressure and 750°F steam temperature with two right-angle bends. Tests at room temperature have been made with controlled anchor movements corresponding to those which would occur on cold pull-up, thermal expansion, or pure bending, all without internal pressure. In addition tests have been made with internal pressure only, and with internal pressure combined with controlled anchor movements. Further tests were carried out by heating the pipeline and measuring the increase of the forces at the restrained anchors, but no strain measurements were made at high temperatures.

The results show that the calculation methods are sufficiently reliable for predicting the forces and stresses in such a pipeline, having regard to the allowable tolerances on pipe dimensions.

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