Rectangular Tubesheets—Application to Power Plant Condensers

Abstract

In previous chapters dealing with tubesheet stress analysis, we have focused exclusively on circular units and we have assumed that tubesheet geometry, loading, and edge conditions did not vary around the periphery. These restrictions permitted us to develop considerably detailed analytical models, leading either to numerical solution procedures, or to simplified, almost closed form, analytical solutions. Since the large majority of tubesheets are of circular shape, these analyses and solution methods have wide applicability. Tubesheets of non-circular shapes, however, are also used, particularly in low pressure, large volume flow rate conditions. Specifically, in this chapter, we will focus on the class of rectangular tubesheets used in large power plant condensers. We will provide a detailed discussion of the loading conditions and the geometry to highlight the complexities that obstruct the effort to obtain a satisfactory simplified solution. In the next section, we will first fully describe the power condenser tubesheet environment and provide an overview of the tubesheet design problem. Following this introductory material, we will present a very approximate design method, based on the theory of a beam strip on an elastic foundation. This approximate analysis, although replete with assumptions, both substantiated and unsubstantiated, at least permits investigation of the effect of various tubesheet parameters. We will fully develop the approximate method and show an application of it to the condenser tubesheet design problem.