The Tubesheet Analysis Method in the New HEI Condenser Standards

The new Heat Exchange Institute (HEI) condenser standard [1] provides a method for tubesheet analysis. The historical background of this method is reviewed. The structural design problem of a rectangular tubesheet is described. A condenser tubesheet is seen to be a partially perforated plate on an elastic foundation, with the tubes comprising the foundation. The hydrostatic pull from the waterbox and surface pressure on the tubesheet are the dominant loads. Irregular tube patterns and variation in edge boundary conditions make solution of the plate problem difficult. The HEI proposes a simplified approximation: a narrow strip of tubesheet with its supporting row of tubes, analyzed as a beam on an elastic foundation. A discussion is presented of the assumptions required, allowable stress criteria, and the uncertainties involved. A preloading device is described. Some suggestions for future work are made.