Computational Fluid Dynamic Simulation of High Aspect Ratio Cross-Sectional Orifice Jets: Shape of the Gasket on the Internal Flow

Improved computing power has increased the capacity of numerical modellers to simulate real-life situations with the expectation that results will be useable and accurate. It is easy when modelling physically large geometries to over simplify aspects of the model, usually because of mesh restrictions, that could be to the detriment of the results. For many years Computational Fluid Dynamics has been used to simulate leaks of hydrocarbons with the production areas of offshore superstructures, [1, 2]. Many simplifications are required, one of which is modelling these leaks as axisymmetric jets. Previous work, [3, 4] has shown that this is not a good simplification and could have serious safety implications. A more accurate model of the jet is needed for the full consequences of a gas leak to be ascertained. Having established that a leak from a flange or crack in a pipe needs to be modelled as a high aspect ratio cross-sectional orifice jet there are also other considerations. Work on the turbulence model and inlet conditions that are best suited for these simulations has been done, [5, 6]. This paper investigates the flow within the pipe and up through the gasket before release into the air as a jet. Different idealised shapes of gaskets are used and the flow at the jet exit are investigated. It is hoped that a range of conditions can be established that set criteria for such modelling in the future.Copyright © 2004 by ASME