Prevention of Transformer Tank Explosion: Part 4—Development of a Fluid Structure Interaction Numerical Tool

Abstract

Oil filled transformer explosions and their prevention is a complex industrial issue. Experimental tests showed that when an electrical fault occurs in a transformer, it generates dynamic pressure waves that propagate in the oil. Reflections of these waves on the walls build up high static pressure which transformer tanks cannot withstand. The tank’s ability to withstand this pressure is thus one of the key parameters of transformer explosion prevention, and a numerical tool was developed to simulate the phenomena highlighted during the tests, especially the pressure wave propagation. The present paper’s aim is thus to complete this numerical tool so that the mechanical behavior of the tank can be accurately studied. The hydrodynamic numerical tool was subsequently coupled with a dynamic structure analysis package: the open source software Code_ASTER. A weak coupling strategy was first developed by applying the simulated pressures to the structure geometry in order to evaluate stresses and deformations. This strategy has evolved with the development of a strong coupling strategy which required establishing a moving mesh technique for the hydrodynamic code to accept displacement data from the structure code and complete the exchange between hydrodynamic and structure codes. First encouraging results are shown.