Determination of flow rate characteristics of porous media using charge method

When flowing through porous media, it is generally known that Darcy regime and Forchheimer regime respectively provide a good approximate characterization in different velocity regions. In this study, a charge method employing an isothermal chamber and a pressure differentiator to determine the permeability coefficient and inertia coefficient is proposed, and its validity is verified by using a series of metal sintered porous media to conduct investigations on flow rate characteristics. The charge method has advantages over the conventional steady state method for it takes only seconds to finish the test and consumes less air. Results of the charge process are separated into a strict Darcy region and a quasi-Forchheimer region, with the flow velocity of 0.1 m/s as the boundary. Experimental data are first used to determine the permeability coefficient in Darcy region, and then the inertia coefficient in Forchheimer region. The permeability coefficient is measured within a 3% uncertainty. Also, it is confirmed that the calculated flow rate show good agreement with the experimental data. Finally, a principle, of general application, for selecting a chamber volume to ensure adequate accuracy of the acquired data is provided.

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► A charge method is developed for characterizing porous media.
► Darcy regime and Forchheimer regime are considered including effects from both viscosity and inertia.
► The charge method is characterized by the reduction in testing time and air consumption.
► Theoretical flow rate show good agreement with the experimental results.
► A general principle for selecting appropriate chamber volume is presented.