A numerical study of a crimped flame arrestor element flow characteristics was conducted using a porous media model. The porous zone was modeled using the Forchheimer equations. The Forchheimer equations were incorporated into the governing equations for turbulent flow as a momentum sink. A small-scale crimped flame arrestor element was tested to determine the Forchheimer equation proportionality coefficients.  The numerical simulation result using this porous media model was verified using the experimental data. The flow characteristics of a four-inch detonation flame arrestor, with the same crimp design as the small-scale sample, was simulated using the porous media model. The numerical simulation flow data were compared against experimental values and agreed to within five percent.  The method used to determine the Forchheimer equation proportionality coefficients and the experimental test setup is explained in detail. The integration of the Forchheimer equation into the governing turbulent flow equations is presented. The challenges and limitations of numerical studies in flame arrestors applications are discussed. The simplification gained by using the porous media model in flame arrestor numerical studies is presented.

Flame arrestors are devices used for safety in pipes transporting flammable gas or vapors, where there is the potential for ignition source. The pressure-drop across inline flame arrestors is one of the key design characteristics for these pipeline system designs. The pressure drop across the flame arrestor is predominantly associated with the crimp design of the flame arrestor element. In the flame arrestor applications, the flow characteristics are usually studied experimentally and empirically. This paper presents the development and verification of numerical method using the porous media model for crimped flame arrestor applications

Typical flame arrestor designs will have a crimped flame arrestor element that is used to extinguish flame/detonation propagation by removing a significant amount of heat and restricting the flow passage area. It is made by crimping sheet metal to form small triangular channels. The flame/detonation propagation is interrupted by the arrestor element, due to the removal of heat by large contact surface area through these channels and restriction on detonation cell formation. The flow in the arrestor element is three dimensional, making it difficult to model numerically. To overcome the complexity of directly modelling this three-dimensional flow, a porous media model is developed using the Forchheimer equation.

The Forchheimer equation proportionality coefficients are calculated using the flow test data. The pressure-drop across the small-scale flame element versus the average velocity is fitted to quadratic equation, Forchheimer equation. This equation is used as a momentum sink in the governing equation for the turbulent flow, to model the arrestor element numerically.


Numerical Study of the Pressure Drop in a Flame Arrestor Using a Porous Media Model

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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