Experimental Study of Surface and Interior Combustion Using Composite Porous Inert Media

Marbach, Timothy; Agrawal, Ajay K.

doi:10.1115/1.1789516

Cited by 43 publications

(13 citation statements)

References 11 publications

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“…Coating of carbon foams with reinforcing material can potentially eliminate cracking and achieve high structural strength in PMBs. Studies using coated carbon foams have successfully achieved combustion without incurring material degradation [12,29].…”

Section: Durability Testingmentioning

confidence: 99%

Investigation of Lean Combustion Stability, Pressure Drop, and Material Durability in Porous Media Burners

Sobhani

Haley²,

Bartz³

et al. 2017

Volume 5C: Heat Transfer

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The operational stability and thermal durability of combustion in two-zone porous media burners (PMBs) is examined experimentally and computationally. Long-term material durability tests at constant and cycled on-off conditions are performed, along with a characterization of combustion stability, pressure drop and pollutant emissions for a range of equivalence ratios, mass flow rates, and burner setups. Experimental thermocouple temperature measurements and pressure drop data are presented and compared to results obtained from one-dimensional volume-averaged simulations. Experimental and model results show good agreement for temperature profiles and pressure drop evaluated using the Darcy-Forchheimer equation with Ergun's relations. Enhanced flame stability is observed for burners with Yttria-stabilized Zirconia Alumina (YZA) upstream and Silicon Carbide (SiC) in the downstream combustion zone. Measurements of product gas concentrations illustrate highest emissions of CO at conditions close to flash-back and, as expected, higher NO x emissions with increasing equivalence ratios.

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Section: Durability Testingmentioning

confidence: 99%

Investigation of Lean Combustion Stability, Pressure Drop, and Material Durability in Porous Media Burners

Sobhani

Haley²,

Bartz³

et al. 2017

Volume 5C: Heat Transfer

View full text Add to dashboard Cite

show abstract

“…Flow resistance associated with the PIM was modeled by sink terms in the momentum conservation equations. The sink term is expressed as a power law correlation with experimentally determined coefficients [25]. An effective thermal conductivity was used to account for the solid and fluid thermal conductivities weighted by the porosity of the PIM.…”

Section: Cfd Analysismentioning

confidence: 99%

“…The pore density is specified in terms of pores per inch or pores per centimeter (ppcm). Porosity and pore density affect the flow resistance or pressure drop across the porous material [25].…”

Section: Introductionmentioning

confidence: 99%

Passive Control of Noise and Instability in a Swirl-Stabilized Combustor With the Use of High-Strength Porous Insert

Sequera

Agrawal

2012

Journal of Engineering for Gas Turbines and Power

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Swirl-stabilized combustion and porous inert medium (PIM) combustion are two methods that have been used extensively, although independently, for flame stabilization. In this study, the two concepts are combined so that the porous insert serves as a passive device to mitigate combustion noise and instabilities. A properly shaped PIM is placed within the combustor to directly influence the turbulent flow field and vortical and/or shear layer structures associated with the outer recirculation zone and inner recirculation zone. After presenting the concept, the paper provides a conceptual understanding of the changes in the mean flow field caused by the PIM. Combustion experiments were conducted at atmospheric pressure using HfC/SiC coated open-cell foam structures of different pore sizes and shapes. Measurements of sound pressure level (SPL) and CO and NO x emissions were taken for different equivalence ratios and reactant flow rates. Combustion mode and PIM geometry to decrease the SPL are identified. The results show that the porous insert can reduce combustion noise without adversely affecting NO x and CO emissions. Experiments show that the proposed concept can also mitigate combustion instabilities encountered at high reactant flow rate.

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“…Both porosity and pore density of the insert affect the flow structure and pressure drop across the PIM [28], Marbach and Agrawal [28] have also demonstrated that PIM can be used to extend the lean blow-off limit. 137, APRIL 2015 state of the art 3D manufacturing techniques.…”

Section: (A ) S C H E M a T Ic D Ia G R A M A N D (B) P H O T O G R Amentioning

confidence: 99%

Time-Resolved Particle Image Velocimetry Measurements of Nonreacting Flow Field in a Swirl-Stabilized Combustor Without and With Porous Inserts for Acoustic Control

Meadows

Agrawal

2014

Journal of Engineering for Gas Turbines and Power

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Combustion noise and thermo-acoustic instabilities are of primary importance in highly critical applications such as rocket propulsion systems, power generation, and jet propulsion engines. Mechanisms for combustion instabilities are extremely complex because they often involve interactions among several different physical phenomena such as unsteady flame propagation leading to unsteady flow field, acoustic wave propagation, natural and forced hydrodynamic instabilities, etc. In the past, we have utilized porous inert media (PIM) to mitigate combustion noise and thermo-acoustic instabilities in both lean premixed (LPM) and lean direct injection (LDI) combustion systems. While these studies demonstrated the efficacy of the PIM concept to mitigate noise and thermo-acoustic instabilities, the actual mechanisms involved have not been understood. The present study utilizes time-resolved particle image velocimetry (PIV) to measure the turbulent flow field in a nonreacting swirl-stabilized combustor without and with PIM. Although the flow field inside the annulus of the PIM cannot be observed, measurements immediately downstream of the PIM provide insight into the turbulent structures. Results are analyzed using the proper orthogonal decomposition (POD) method and show that the PIM alters the flow field in an advantageous manner by modifying the turbulence structures and eliminating the corner recirculation zones and precessing vortex core (PVC), which would ultimately affect the acoustic behavior in a favorable manner.

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Experimental Study of Surface and Interior Combustion Using Composite Porous Inert Media

Cited by 43 publications

References 11 publications

Investigation of Lean Combustion Stability, Pressure Drop, and Material Durability in Porous Media Burners

Investigation of Lean Combustion Stability, Pressure Drop, and Material Durability in Porous Media Burners

Passive Control of Noise and Instability in a Swirl-Stabilized Combustor With the Use of High-Strength Porous Insert

Time-Resolved Particle Image Velocimetry Measurements of Nonreacting Flow Field in a Swirl-Stabilized Combustor Without and With Porous Inserts for Acoustic Control

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