A CFD pressure drop model for microfibrous entrapped catalyst filters using micro-scale imaging

Abstract

A micro-scale pressure drop model for microfibrous entrapped catalysts (MFEC) is constructed based on experimental scanning electron microscope (SEM) images using computational fluid dynamics (CFD). This model investigates the separate contributions of fibers, entrapped particles, particle shape factors and the compressibility of MFEC to the total pressure drop in a high air velocity condition. A theoretical calculation is conducted to determine the flow type within the MFEC. Top view and side view SEM images of MFEC are taken to reproduce their 3D geometric structure, which significantly improves the accuracy of the model compared with other simplified models. Volume loading of fibers and entrapped particles, as well as media compressibility, are found to be major contributors to pressure drop. In an effort to reduce pressure drop, two types of leading-edge/trailing-edge filter fairings are also studied. Triangle fairings added to the leading edge and trailing edge of MFEC decrease pressure drop, especially at higher face velocities.Keywords: pressure drop; computational fluid dynamics (CFD); scanning electron microscope (SEM); microfibrous entrapped catalysts (MFEC)

Comparison of Packed Beds, Washcoated Monoliths, and Microfibrous Entrapped Catalysts for Ozone Decomposition at High Volumetric Flow Rates in Pressurized Systems

“…25 Reynolds number analysis for packed beds and monolith also indicate turbulent flow in these reactors. This result has been verified by a numerical analysis, 26 in which velocity profile within MFEC is acquired by the Navier−Stokes equation. Plug flow is found to exist in this velocity range within a very thin boundary layer.…”

“…This result has been verified by a numerical analysis, in which velocity profile within MFEC is acquired by the Navier–Stokes equation. Plug flow is found to exist in this velocity range within a very thin boundary layer . The mass balance for a plug-flow reactor is given by It has been previously determined that ozone decomposition at high face velocity is a mass-transfer-limited reaction .…”

“…Plug flow is found to exist in this velocity range within a very thin boundary layer. 26 The mass balance for a plug-flow reactor is given by…”

“…The mass efficiency term in HCE for the MFEC reactor was measured using a tubular reactor at different system pressures. Previous efforts 26 have been made to use both experimental and computational fluid dynamics (CFD) techniques to determine the pressure-drop term for MFECs. Because the geometric structure of an MFEC is affected when the system pressure changes, the experimental pressure drop was preferred in this study to avoid erroneous assumptions during simulations.…”

Macro-scale modeling and simulation of two-phase flow in fibrous liquid aerosol filters

“…In the experimental works, the evolvement of pressure loss over the filter lifetime and the evolution of fractional efficiency and its dependence on parameters like flow velocity and fluid properties have mainly been investigated (Charvet et al, 2008;Frising et al, 2004Frising et al, , 2005Gu et al, 2015;Payet et al, 1992;Raynor & Leith, 2000). Partially, phenomenological models were developed based on experimental results, e.g.…”