PSI - Issue 60

3

Akshay Kumar/ Structural Integrity Procedia 00 (2023) 000 – 000

A. Kumar et al. / Procedia Structural Integrity 60 (2024) 541–552

543

condition. The ends of CT are fixed to the water tank with the help of specially designed flanges and silicon rubber packing. The PT having 82.55 mm inner diameter and 3.32 mm thickness is concentrically placed inside the CT of 107.7 mm ID. The length of PT and CT is around 1.5 m and 1 m, respectively. One of the extended ends of the PT is fixed to a support and the other end is simply supported to accommodate the longitudinal thermal expansion. Both the ends of PT are connected to the rectifier with the help of copper clamps and bus bars. One end of the PT was connected to Argon gas cylinder with feedback system to control the pressure inside the PT. A schematic of the section in which the PT is heated, is shown in Fig, 1. The PT was heated slowly until it attained steady state temperature of around 300 o C. The water in the outer tank which simulates the calandria vessel is maintained at 52 o C. The PT was pressurized by argon gas. The experiment was performed for two pressure condition i.e. 4MPa and 6MPa under different heat up rates of 21KW and 14KW symmetrical heating respectively. 2.1. Model for estimation of the ballooning behavior The ballooning behaviour and the estimate of time to contact of PT and CT under given input conditions is modelled using finite element (FE) analysis. FE Analysis involves thermal analysis and structural analysis. With the help of thermal analysis, temperature distribution along the circumference of the pressure tube is calculated. This temperature profile acts as an input data for structural analysis which predicts the deformation of the PT. Thus, the contact time between PT and CT can be calculated.

Fig. 1: (a) Schematic of the high temperature ballooning experiment of pressure tube subjected to internal pressure loading; (b) Symmetric 3D finite element model of the pressure tube subjected to internal pressure and heating (the heating is simulated by inclusion of equivalent volumetric heating of the pressure tube and the heat transfer to the surrounding is simulated by equivalent resistance)