Applications of Porous Media Combustion Technology

Mujeebu, M. Abdul; Mohamad, A. A.; Abdullah, M. Z.

doi:10.1016/b978-0-444-63283-8.00024-7

Cited by 10 publications

(6 citation statements)

References 43 publications

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“…Figure 2 displays a view of the PM diesel engine. PM inserts in the cylinder head of a diesel engine, and permanent contact between the in-cylinder mixture and PM (open PM concept) exists [3][4][5][6].…”

Section: Figurementioning

confidence: 99%

“…The high initial PM temperature (solid-phase temperature of the PM and gas temperature trapped inside PM volume) with mixture formation inside the PM reactor causes self-ignition and volumetric heat release in the combustion process. The reactor heat capacity, pore density, and pore structure can affect the combustion process [2][3][4][5][6][7].…”

Section: Diesel Pm-engine With Concept Of An Open Pm Chambermentioning

confidence: 99%

“…The PM structure creates conditions for a homogeneous combustion process and converts the heat into work (Figure 3e). The combustion in a PM can be carried out in the PM volume that cannot occur in the free flame combustion process [1][2][3][4][5][6][7].…”

Section: Diesel Pm-engine With Concept Of An Open Pm Chambermentioning

confidence: 99%

“…One of the different combustion technologies is inside PM combustion. It is a flameless heat release inside an operating PM followed by homogeneous combustion with near-zero emission [1][2][3]. This process is stable combustion with a high-power density in an extensive dynamic range.…”

Section: Introductionmentioning

confidence: 99%

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Mathematical Modeling of a Porous Medium in Diesel Engines

Mohammadi

2023

Numerical Simulation - Advanced Techniques for Science and Engineering

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Direct injection diesel engines have high power density with low exhaust emission but suffer from particulate matter (PM). Some new technologies were applied to reduce emissions, but they have not solved the emission problem of diesel engines altogether. The main problem of emissions from diesel engines is the simultaneous process of fuel injection and combustion, so non-homogeneous mixture formation occurs in cylinder space, and non-homogeneity is the main reason for emission generation. The solution to this problem is the separation of injection fuel and combustion processes for homogeneous mixture formation in diesel engines. An applicable practical solution for homogeneous mixture formation is the application of porous media (PM) in diesel engine combustion chambers. PM develops stable ultra-lean combustion and decreases emissions. This chapter has three parts for the mathematical modeling of PM diesel engines. The first part is thermodynamically modeling in a closed cycle. The second is zero-dimensional modeling with the chemical kinetics of PM diesel engines, and the third is three-dimensional CFD modeling with the chemical kinetics of PM diesel engines in open or closed cycle. So, mathematical modeling of PM diesel engines, from simple thermodynamically modeling to complicated 3D modeling, is described in this chapter.

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Section: Figurementioning

confidence: 99%

Section: Diesel Pm-engine With Concept Of An Open Pm Chambermentioning

confidence: 99%

Section: Diesel Pm-engine With Concept Of An Open Pm Chambermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mathematical Modeling of a Porous Medium in Diesel Engines

Mohammadi

2023

Numerical Simulation - Advanced Techniques for Science and Engineering

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“…For a detailed account of the development of macroscale turbulence models in porous media, see de Lemos (2012), Lage, de Lemos & Nield (2007), Vafai (2015) and Vafai et al (2009). These models enabled the study of transport processes in physical systems as applied to canopy flows, pebble-bed nuclear reactors, heat exchangers, porous chemical reactors and crude oil extraction, to name a few applications (Jiang et al 2001;Mujeebu, Mohamad & Abdullah 2014;Wood, He & Apte 2020). However, there are a lot of unanswered questions about the flow physics of turbulence in porous media.…”

Section: Introductionmentioning

confidence: 99%

Symmetry breaking of turbulent flow in porous media composed of periodically arranged solid obstacles

Srikanth

Huang

et al. 2021

J. Fluid Mech.

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The focus of this paper is a numerical simulation study of the flow dynamics in a periodic porous medium to analyse the physics of a symmetry-breaking phenomenon, which causes a deviation in the direction of the macroscale flow from that of the applied pressure gradient. The phenomenon is prominent in the range of porosity from 0.43 to 0.72 for circular solid obstacles. It is the result of the flow instabilities formed when the surface forces on the solid obstacles compete with the inertial force of the fluid flow in the turbulent regime. We report the origin and mechanism of the symmetry-breaking phenomenon in periodic porous media. Large-eddy simulation (LES) is used to simulate turbulent flow in a homogeneous porous medium consisting of a periodic, square lattice arrangement of cylindrical solid obstacles. Direct numerical simulation is used to simulate the transient stages during symmetry breakdown and also to validate the LES method. Quantitative and qualitative observations are made from the following approaches: (1) macroscale momentum budget and (2) two- and three-dimensional flow visualization. The phenomenon draws its roots from the amplification of a flow instability that emerges from the vortex shedding process. The symmetry-breaking phenomenon is a pitchfork bifurcation that can exhibit multiple modes depending on the local vortex shedding process. The phenomenon is observed to be sensitive to the porosity, solid obstacle shape and Reynolds number. It is a source of macroscale turbulence anisotropy in porous media for symmetric solid-obstacle geometries. In the macroscale, the principal axis of the Reynolds stress tensor is not aligned with any of the geometric axes of symmetry, nor with the direction of flow. Thus, symmetry breaking in porous media involves unresolved flow physics that should be taken into consideration while modelling flow inhomogeneity in the macroscale.

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