The atomization mechanism of the gas-liquid multiphase flow through internally mixing twin-fluid Yjet atomizer has been studied by examining both the internal and external flow patterns. Superheated steam and Light Fuel Oil (LFO) are used as working fluids. The flow is numerically modeled using the compressible Navier-Stokes equations; hybrid Large Eddy Simulation approach through Wall Modeled Large Eddy Simulations (WMLES) is used to resolve the turbulence with the Large Eddy Simulations, whereas the Prandtl Mixing Length Model is used for modeling the subgrid-scale structures, which are affected by operational parameters. VOF-to-DPM transition mechanism is utilized along with dynamic solution-adaptive mesh refinement to predict the initial development and fragmentation of the gas-liquid interface through Volume-of-Fluid (VOF) formulations on a sufficiently fine mesh, while Discrete Phase Model (DPM) is used to predict the dispersed part of the spray on the coarser grid. Two operational parameters, namely gas-to-liquid mass flow rate ratio (GLR) and liquid-to-gas momentum ratio are compared; the latter is found to be an appropriate operational parameter to describe both the internal flow and atomization characteristics. It is confirmed that the variation in the flow patterns within the mixing-port of the atomizer coincides with the variation of the spatial distribution of the spray drops.

Deepwater exploration and production presents some of the industry's most complex challenges, requiring huge capital investment and long-term commitment. Subsea fields face exceptional challenges during drilling, cementing, and operations. Any downtime means project delay and lost production. Consequently, it is important to have real-time data from high-fidelity measurement-while-drilling (MWD) and logging-while-drilling (LWD) tools during drilling operations. Mud pulse telemetry is a widely used method to transmit MWD and LWD data to the surface. Availability of this real-time data is important for the economic success of the drilling operation. Consequently, it is important to maintain operational telemetry systems that provide fast and reliable data rates for downhole drilling. However, telemetry system failure due to sand erosion can be costly and cause downtime and maintenance costs to the operators. Hence, there is a constant need for accurate prediction of the location and erosion rate of these downhole systems. In this study, we build on our earlier work, where we presented a comprehensive investigation on erosion of mud pulse telemetry tools consisting of numerical simulations and field data. In the current work, we take the numerical analysis further: we predict the location of the high erosion rates and model equipment topological changes due to sand erosion and its impact to fluid flow. The importance of this step is to capture the effect of changing geometry on the erosion rate, enabling us to estimate the reliability of the tool accurately. In addition, we investigate the structural integrity of the tool and the effect that sand erosion has on it. Structural integrity analysis of the eroded tool geometry is performed using finite element analysis (FEA). For model validation, simulation results will be compared with erosion patterns from field tests.

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