The effects of fluid flow geometry on the physics of flow

The effects of fluid flow geometry on the physics of fluid are of prime importance as optimisation of the geometry could lead to improved fluid flow for various engineering applications. One such area that has led to substantial research in the commercial and academic sectors is the oil industry. Coning is a phenomenon which occurs because of the difference in pressure drop between the heel and toe ends of the oil well leading to non-uniform pressure along the well-bore. This phenomenon is quite common with oil wells and causes water/gas breakthrough into the oil well leading to reduced oil recovery and increased separation costs. hence the need for different inflow control devices for oil extraction. These devices however, have shown limitations due to the mixing of oil with water and gas causing inefficient valve actuation and resulting in the oil pipeline to shut down. They require optimisation of the fluid flow geometry to ensure maximum turbulence and differential pressure can be generated leading to more oil recovery. Autonomous Inflow Control Valve (AICV) is a commercially available control device that is widely used in oil wells. It is responsible for balancing the pressure drop while making use of a circular coil pipe between the laminar and turbulent flow elements. This research focussed on developing new geometry designs for the coil pipe without increasing the size or robustness of the design that can increase pressure drop and lead to turbulence of the incoming fluid to ensure separation of oil from water/gas. Eight different designs were developed, and numerical analysis was undertaken using ANSYS 19.2 under various boundary conditions. All the designs were analysed for pressure drop values using oil, water and gas as investigative fluids. The CFD (computational fluid dynamics) simulations were undertaken for laminar and turbulent flow regimes for all three fluids because as the AICV functions on these two regimes. The results showed that one of the designs proposed in this work called ‘square swirl slinky coil pipe’ generated the maximum pressure drop for all three fluids. AICV makes use a circular coil pipe that can create a pressure drop of 3.18 Pa for water, 0.05 Pa for gas and 0.13 MPa for oil with laminar flow whereas the square swirl slinky coil pipe can create a pressure drop of 66.11 Pa for water, 0.8 Pa for gas and 2.98 MPa for oil with laminar flow. On the other hand, a circular coil pipe can create a pressure drop of 167 Pa for water, 2.41 Pa for gas and 6.6 MPa for oil with turbulent flow whereas the square swirl slinky coil pipe can create a pressure drop of 2,361 Pa for water, 33.54 Pa for gas and 93.23 MPa for oil with turbulent flow. The new geometry has shown massive increases in the pressure drop that can help in a substantially large amount of oil extraction compared to a commercially available product. This work highlights the importance of optimising fluid flow geometry parameters that can affect the physics of flow to achieve optimum results for a specific application. This work has wider implications in other areas as well e.g., turbulence is a major factor in enhancing heat transfer which makes this square slinky coil pipe design an optimal choice for heat exchangers and thermal solar panels.