A combined numerical and experimental study on metal expansion bellows for STHE

Abstract

Bellows is the pliable component of an expansion joint comprises one or more convolutions and the end tangents. The numbers of convolutions in a bellows are in direct connection to the extent of thermal or mechanical crusade in the piping system or heat exchanger. Metal bellows compressed under pressure and protracted under void. The bellows returns to its usual shape as the pressure or vacuum release. The aim of this paper is to design and investigate the performance of the metal expansion bellows as per the ASME and Expansion Joint Manufactures Association standards. The Johnson method of optimum design is applied to select the optimum material with the objective to minimize weight and cost. As per Johnson method, the material selected for bellows under consideration is SAE 240 321 for minimum weight and cost as compared to materials like Inconel and Hastelloy X. Analytical analysis is performed for bellows with 8, 9 and 10 convolutions, and it is found that the circumferential membrane stress in bellows tangent (S1) is constant for bellows with 8, 9 and 10 convolutions, whereas the end convolution circumferential membrane stress (S2E) and intermediate convolution circumferential membrane stress (S2I) show the linear decrement in stress as the number of convolution increases. In order to substantiate the findings, the numerical analysis is also performed using ANSYS software and comprehensive experimentation using data acquisition system. After comparing the results, it is observed that all findings are in worthy covenant.