COMPUTATIONAL FLUID DYNAMICS MODELLING OF A COLLAPSE OF A STORAGE TANK

Above ground storage tanks are containers used in many industries to store materials such as chemicals including oil and other hydrocarbons. Regulations require that these tanks should be surrounded by bund walls or secondary containment to alleviate the extent of any incident that may occur upon a catastrophic failure of the primary containers. Existing bund walls have been shown to be inadequate to withstand the impact of surge waves of the escaping stored material, which has resulted in tragic consequences for the environment, the economy and the immediate community. This research investigates the problem of catastrophic failure of a storage tank, which falls within the multiphase type of flow. Numerical simulations are based on the Volume Tracking Method that uses the volume fraction as an indicator to represent the interface between the two different fluids. The conservation equations are discretised using the Finite Volume Method and solved in a procedural manner based on the Pressure Implicit with Splitting of Operator (PISO) to account for the transient term in the equation. The turbulence is modelled using a low Reynolds number Shear Stress Transport (SST) k-ω model. The SST k-ω model is ideal for non-fully turbulent flows with separation where the values of the dynamic pressure on the bund walls are of paramount importance. Finally, the results are validated with reference to physical experimental results using scaled model testing which cover a wide range of tank/bund configurations of different shapes of bund and capacity along with the effect of temperature.