Orifice for Methane Gas Flow, CFD Approach

ANSYS Fluent Simulations of Methane Gas Flow Through an Orifice

Problem Statement

This work simulates methane gas flow across an aperture inside a channel using a CFD model.  Designed in 3D with Design Modeler tools, the model represents a 12-inch long channel with a 0.5-inch diameter and a center orifice with a 0.25-inch diameter.

Orifice Model and Meshing

A perforated plate placed perpendicularly to the direction of fluid flow forms the most basic orifice model.  Using a structured mesh with 54,648 elements to guarantee accurate simulation results, this model is meshed using ANSYS Meshing software.

Orifice Methodology

Mass flow through pressure difference transmitters is routinely measured using the orifice equipment.  Following Bernoulli's principle and mass conservation, a fluid's velocity increases as it passes through an aperture from decreased cross-sectional area.  Velocity reduces as the area grows upon leaving, which raises flow pressure.

Key Parameters and Simulation Setup

• Fluid Properties: methane gas with viscosity of 0.00001087 kg/m.s. and density of 0.6679 kg/m³.
• Flow Conditions: Methane leaves at atmospheric pressure after entering the pipe at 0.033 m/s.
• Turbulence Model: The RNG k-epsilon model is applied in the simulation to solve turbulent flow equations.

Results and Conclusion

Along with graphs of pressure and velocity changes across the central axis and through the orifice section, the simulation generates two- and three-dimensional velocity and pressure contours.

Results Analysis

• Reduced cross-sectional area causes visible increased velocity at the oracle to match Bernoulli's principle's expectations.
• Pressure differential measurements let one to examine the clearly visible matching pressure drop in the fluid flow through the oracle.

This study exemplifies the orifice’s capability in determining fluid flow rates accurately by analyzing pressure differences, providing valuable insights into flow dynamics for engineering applications. If you’re interested in further details or need guidance on similar simulations, feel free to reach out!