Assessment of Different Pressure Drop-Flow Rate Equations in a Pressurized Porous Media Filter for Irrigation Systems

The small open area available at the slots of underdrains in pressurized granular bed filters for drip irrigation implies: (1) existence a region with non-uniform flow, and (2) local values modified particle Reynolds number >500. These flow conditions may disagree those accepted as valid common pressure drop-flow rate correlations proposed packed beds. Here, we carried out detailed computational fluid dynamics (CFD) simulations laboratory filter to analyze results obtained five different equations head losses porous media: Ergun, Darcy-Forchheimer, (3) Darcy, (4) Kozeny-Carman (5) power function. Simulations were compared experimental data superficial velocities from previous studies. Results two silica sand media indicated that all predicted total drop within uncertainty range when <38.3 m h−1. At higher rates, Ergun equation approximated best observed media, being expression recommended. A simple analytical model along streamlines matched CFD simulation was developed.