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Hazim, Ammar
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Publications (8 of 8) Show all publications
Göktepe, B., Umeki, K., Hazim, A., Lundström, S. & Gebart, R. (2017). Soot reduction in an entrained flow gasifier of biomass by active dispersion of fuel particles. Paper presented at 1st International Workshop on Oxy-Fuel Combustion, Montabaur, Germany, 10-11 February 2016. Fuel, 201, 111-117
Open this publication in new window or tab >>Soot reduction in an entrained flow gasifier of biomass by active dispersion of fuel particles
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2017 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 201, p. 111-117Article in journal (Refereed) Published
Abstract [en]

Soot is an undesired by-product of entrained flow biomass gasification since it has a detrimental effect on operation of the gasifier, e.g. clogging of flow passages and system components and reduction of efficiency. This study investigated how active flow manipulation by adding synthetic jet (i.e. oscillating flow through orifice) in feeding line affects dispersion of fuel particles and soot formation. Pine sawdust was gasified at the conditions similar to pulverized burner flame, where a flat flame of methane-air sub-stoichiometric mixture supported ignition of fuel particles. A synthetic jet flow was supplied by an actuator assembly and was directed perpendicular to a vertical tube leading to the center of the flat flame burner through which pine sawdust with a size range of 63–112 μm were fed into a reactor. Quartz filter sampling and the laser extinction methods were employed to measure total soot yield and soot volume fraction, respectively. The synthetic jet actuator modulated the dispersion of the pine sawdust and broke up particle aggregates in both hot and cold gas flows through generation of large scale vortex structures in the flow. The soot yield significantly reduced from 1.52 wt.% to 0.3 wt.% when synthetic jet actuator was applied. The results indicated that the current method suppressed inception of young soot particles. The method has high potential because soot can be reduced without changing major operation parameters.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Energy Engineering Fluid Mechanics and Acoustics
Research subject
Energy Engineering; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-59714 (URN)10.1016/j.fuel.2016.09.039 (DOI)000402943900012 ()2-s2.0-84994765423 (Scopus ID)
Conference
1st International Workshop on Oxy-Fuel Combustion, Montabaur, Germany, 10-11 February 2016
Note

2017-06-02 (andbra);Konferensartikel i tidskrift

Available from: 2016-10-13 Created: 2016-10-13 Last updated: 2018-07-10Bibliographically approved
Hazim, A., Göktepe, B., Umeki, K., Lundström, S. & Gebart, R. (2016). Active fuel particles dispersion by synthetic jet in an entrained flow gasifier of biomass: Cold flow. Powder Technology, 302, 275-282
Open this publication in new window or tab >>Active fuel particles dispersion by synthetic jet in an entrained flow gasifier of biomass: Cold flow
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2016 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 302, p. 275-282Article in journal (Refereed) Published
Abstract [en]

Pulverized fuel (PF) burners play a key role for the performance of PF fired gasification and combustion plants, by minimizing pollutant emission, fuel consumption and hence fuel costs. However, fuel diversity in power generation plants imposes limitations on the performance of existing PF burners, especially when burning solid fuel particles with poor flowability like biomass sawdust. In the present study, a vertically downward laminar flow was laden with biomass particles at different particle mass loading ratios, ranging from 0.47 to 2.67. The particle laden flow was forced by a synthetic jet actuator over a range of forcing amplitudes, 0.35–1.1 kPa. Pulverized pine particles with a sieve size range of 63–112 μm were used as biomass feedstock. Two-phase particle image velocimetry was applied to measure the velocity of the particles and air flow at the same time. The results showed that the synthetic jet had a large influence on the flow fields of both air and powdered pine particles, via a convective effect induced by vortex rings that propagate in the flow direction. The particle velocity, particle dispersion and hence inter-particle distance increased with increasing forcing amplitude. Moreover, particles accumulated within a specific region of the flow, based on their size. The effect on particle dispersion was more pronounced in the forced flows with low mass loading ratios

National Category
Energy Engineering Fluid Mechanics and Acoustics
Research subject
Energy Engineering; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-59675 (URN)10.1016/j.powtec.2016.08.071 (DOI)000386420500027 ()2-s2.0-84984837775 (Scopus ID)
Note

Validerad; 2016; Nivå 1; 2016-10-11 (andbra)

Available from: 2016-10-12 Created: 2016-10-12 Last updated: 2018-07-10Bibliographically approved
Göktepe, B., Hazim, A., Gebart, R. & Lundström, S. (2016). Cold flow experiments in an entrained flow gasification reactor with a swirl-stabilized pulverized biofuel burner (ed.). International Journal of Multiphase Flow, 85, 267-277
Open this publication in new window or tab >>Cold flow experiments in an entrained flow gasification reactor with a swirl-stabilized pulverized biofuel burner
2016 (English)In: International Journal of Multiphase Flow, ISSN 0301-9322, E-ISSN 1879-3533, Vol. 85, p. 267-277Article in journal (Refereed) Published
Abstract [en]

Short particle residence time in entrained flow gasifiers demands the use of pulverized fuel particles to promote mass and heat transfer, resulting high fuel conversion rate. The pulverized biomass particles have a wide range of aspect ratios which can exhibit different dispersion behavior than that of spherical particles in hot product gas flows. This results in spatial and temporal variations in temperature distribution, the composition and the concentration of syngas and soot yield. One way to control the particle dispersion is to impart a swirling motion to the carrier gas phase. This paper investigates the dispersion behavior of biomass fuel particles in swirling flows. A two-phase particle image velocimetry technique was applied to simultaneously measure particle and gas phase velocities in turbulent isothermal flows. Post-processed PIV images showed that a poly-dispersed behavior of biomass particles with a range of particle size of 112-160 μm imposed a significant impact on the air flow pattern, causing air flow decelerated in a region of high particle concentration. Moreover, the velocity field, obtained from individually tracked biomass particles showed that the swirling motion of the carrier air flow gives arise a rapid spreading of the particles

National Category
Fluid Mechanics and Acoustics Energy Engineering
Research subject
Fluid Mechanics; Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-12400 (URN)10.1016/j.ijmultiphaseflow.2016.06.016 (DOI)000381951000027 ()2-s2.0-84978033454 (Scopus ID)b8a0c0d3-9152-495a-bb2b-c4c628816eaf (Local ID)b8a0c0d3-9152-495a-bb2b-c4c628816eaf (Archive number)b8a0c0d3-9152-495a-bb2b-c4c628816eaf (OAI)
Note

Validerad; 2016; Nivå 2; 20160623 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Hazim, A., Lundström, S. & Hellström, G. (2016). Influence of Inertial Particles on Turbulence Characteristics in Outer and Near Wall Flow as Revealed with High Resolution PIV (ed.). Journal of Fluids Engineering - Trancactions of The ASME, 138(9), Article ID FE-15-1428.
Open this publication in new window or tab >>Influence of Inertial Particles on Turbulence Characteristics in Outer and Near Wall Flow as Revealed with High Resolution PIV
2016 (English)In: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 138, no 9, article id FE-15-1428Article in journal (Refereed) Published
Abstract [en]

A fully developed turbulent particle-gas flow in a rectangular horizontalchannel 100 × 10 × 4000 mm3 is disclosed with high spatial resolution2D Particle Image Velocimetry. The objective is to increase the knowledge ofthe mechanisms behind alterations in turbulent characteristics when adding twosets of relatively large solid spherical particles with mean diameters of 525and 755 μm and particle size distributions of 450 - 600 and 710 - 800 μm,respectively. Reynolds numbers are 4000 and 5600 and relatively high volumefraction of 5.4 × 10-4 and 8.0 × 10-4 are tested. Both thenear wall turbulent boundary layer flow and outer core flow are considered. Resultsshow that the carrier phase turbulent intensities increase with volume fractionof the inertial particles. The overall mean flowvelocity is affected when adding the particles but only to a minor extent. Nearthe wall, averaged velocity decreases while fluctuating velocity componentsincrease when particles are added to the flow. Quadrant analysis shows theimportance of sweep near the wall and ejection events in the region defined byy+ > 20. In conclusion, high inertia particles can enhanceturbulence even at relatively low Particle Reynolds number < 90. In the nearbottom wall region particles tend to be a source of instability reflected asenhancement in rms values of the normal velocity component.

Keywords
Turbulent modulation, solid-gas two-phase flow, near wall boundary layer, PIV, Engineering mechanics - Fluid mechanics, Teknisk mekanik - Strömningsmekanik
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-12548 (URN)10.1115/1.4033369 (DOI)000382748700012 ()2-s2.0-84973897642 (Scopus ID)bb407849-95ab-440d-95ec-2a99e93bf903 (Local ID)bb407849-95ab-440d-95ec-2a99e93bf903 (Archive number)bb407849-95ab-440d-95ec-2a99e93bf903 (OAI)
Note

Validerad; 2016; Nivå 2; 20160330 (ammhaz)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Hazim, A. (2015). Non-Spherical Particle Interaction in Duct and Jet Flow (ed.). (Doctoral dissertation). Paper presented at . : Luleå tekniska universitet
Open this publication in new window or tab >>Non-Spherical Particle Interaction in Duct and Jet Flow
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Wood waste is the most popular biomass recourse for many nations. Burned wood can, direct or indirect, release one of the greenhouse gases, carbon dioxide. The process can still be seen as a renewable source of energy since replanting of the trees and crops are consuming nearly the same amount of carbon dioxide through photosynthesis. Thermal gasification is one of the efficient methods to utilize energy from wood waste. Products from the component of concern can be used for direct energy production like in boilers and gas turbines or indirectly via dimethyl ether (DME), for instance. The physics of gasification is complex and several issues can influence the process. There is a lack of knowledge of several phenomena, some of which are related to solid-gas flow in the gasifier and in the premixed feeding pipelines. One such area is mechanisms related to turbulence modulation in the presence of spherical and non-spherical particles and how much the flow can disturb the motion of the particles. This is studied in the present thesis and the motion of the particles in different flow field is disclosed. At the moment there is no agreement in the scientific community on a single dimensionless number that can safely describe the influence of spherical particles in turbulent flow. For non-spherical particles additional levels of freedom are introduced and the dependence on drag and lift from the orientation of the particles as a function of Reynolds number adds to the complexity.Based on a literature review a fundamental experimental study is carried out in simple flow field geometry, a 2D duct flow. The aim is to reveal the influence of spherical glass particle on the turbulent flow field in the core and near wall flows. Additional studies with wood particles gave more information about how real biomass particles affect the turbulence as compared to spherical ones. Next the instantaneous distribution of biomass particles was studied experimentally. It is known that this distribution significantly influences the soot formation in a gasifier. Two different techniques of flow control were studied, swirling flow and synthetic jet flow. Particles shape and inertia and the strength of vortices and vortices interaction in coaxial jets and swirling jet flow were studied and yielded a high influence on the preferential concentration of particles as well as on the root mean square values for velocity in coaxial jets flow. The synthetic jet add momentum to the flow without disturbing the mass loading ratio and result in higher dispersion of the particles away from the centreline of the jet.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2015. p. 158
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keywords
Solid-gas flow, turbulence modulation, duct flow, coaxial jets flow, swirl jet flow, active flow control, synthetics jet, biomass powder, non-spherical particles, PIV measurement, Engineering mechanics - Fluid mechanics, Teknisk mekanik - Strömningsmekanik
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-26126 (URN)cc6d4c3c-5d28-4525-b3c2-2564a892279e (Local ID)978-91-7583-398-9 (ISBN)978-91-7583-399-6 (ISBN)cc6d4c3c-5d28-4525-b3c2-2564a892279e (Archive number)cc6d4c3c-5d28-4525-b3c2-2564a892279e (OAI)
Note
Godkänd; 2015; 20150907 (ammhaz); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Ammar Hazim Saber Ämne: Strömningslära/Fluid Mechanics Avhandling: Non-Spherical Particle Interaction in Duct and Jet Flow Opponent: Associate Professor Matthias Mandø, Dept of Energy Technology, Aalborg University, Esbjerg, Denmark Ordförande: Professor Staffan Lundström, Avd för strömningslära och experimentell mekanik, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet, Luleå Tid: Onsdag 30 september, 2015 kl 09.00 Plats: E231, Luleå tekniska universitetAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-24Bibliographically approved
Hazim, A., Lundström, S. & Hellström, G. (2015). Turbulent modulation in particulate flow: A review of critical variables (ed.). Paper presented at . Engineering, 7(10), 597-609, Article ID 8102444.
Open this publication in new window or tab >>Turbulent modulation in particulate flow: A review of critical variables
2015 (English)In: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 7, no 10, p. 597-609, article id 8102444Article in journal (Refereed) Published
Abstract [en]

A review of the main mechanisms influencing turbulent modulation in the presence of spherical and non-spherical particles is presented. The review demonstrates the need for more numerical and experimental work with higher accuracy than obtained so far and the need to resolve the flow near the surface of particles with the aim to re-evaluate the quantitative effect of different parameters on turbulent modulation. The review reveals that non-spherical particles have more adverse effect on turbulence as compared to spherical ones, for the same ambient conditions

National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-4479 (URN)10.4236/eng.2015.710054 (DOI)26a39092-3a33-4a42-8c9c-8d0c4bbf1f9a (Local ID)26a39092-3a33-4a42-8c9c-8d0c4bbf1f9a (Archive number)26a39092-3a33-4a42-8c9c-8d0c4bbf1f9a (OAI)
Note
Validerad; 2015; Nivå 1; 20150805 (stlu)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Hazim, A., Lundström, T. S. & Hellström, J. G. (2014). Experimental study of the effect from bio-solid particles on fully developed turbulent duct flow (ed.). Paper presented at European Fluid Mechanics Conference : 14/09/2014 - 18/09/2014. Paper presented at European Fluid Mechanics Conference : 14/09/2014 - 18/09/2014.
Open this publication in new window or tab >>Experimental study of the effect from bio-solid particles on fully developed turbulent duct flow
2014 (English)Conference paper, Oral presentation only (Refereed)
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-40376 (URN)f76dac63-f514-4930-94e3-f7053eb57961 (Local ID)f76dac63-f514-4930-94e3-f7053eb57961 (Archive number)f76dac63-f514-4930-94e3-f7053eb57961 (OAI)
Conference
European Fluid Mechanics Conference : 14/09/2014 - 18/09/2014
Note
Godkänd; 2014; 20140923 (andbra)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Saber, A. (2014). Transport of Particles in Turbulent Flow with Application to Bio-Fuels (ed.). (Licentiate dissertation). Paper presented at . : Luleå tekniska universitet
Open this publication in new window or tab >>Transport of Particles in Turbulent Flow with Application to Bio-Fuels
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Development of civilization faces a challenge of developing the resources of energy demand for the modern life. Extensive use of conventional fuel resources like crude oil and coal rise up a serious problem of increasing CO2 emission. New records levels of CO2 were registered during the early beginning of industrial revolution (http://climate.nasa.gov/evidence). Now a day’s more attention is oriented towards developing of biomass power stations owing to the increasing of conventional fuel prices and due to the potential to be CO2 neutral. One of the essential issues to successfully simulate and design efficient equipment for best utilization of the bio-fuel is to have better understanding of the interaction of bio-particles and the carrier gas. Almost, all two-phase flow system dealing with bio-mass power is turbulent flow. A unifying theory of turbulence does not yet exist. When particles are suspended into such a flow the flow becomes even more complicated and the resulting interactions between the particles and turbulent structures are not fully understood. For non-spherical particles, like most of the bio-mass particles found in cyclone filters and biomass gasification and combustion, the interactions of the particles and the fluid in turbulent flow are extremely complex while theories exists for low Reynolds number flow. The carrier phase turbulence alters the dispersed phase translational and rotational motion and the particles influence the detailed and overall flow of the carrier phase. The presence of the particles may also modify the turbulence of the fluid.To achieve my objective, to study the interaction of bio-particles with the carrier phase, and because of the complexity of the mechanisms related to such flow, it was essential to start to develop the knowledge on the possible mechanisms for the interactions and the importance of each of these interactions, see Paper A. Also, the controlling parameter which may have qualitative and/or quantitative influence of the flow interaction is covered by Paper A. To enable different types of experiments with PIV and LDA, a horizontal rectangular duct was designed and constructed. Design details and test is presented in Paper B. An introductory experimental series was performed in the current set-up using a high spatial resolution PIV system and the results can be found in Paper C.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2014. p. 8
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
Bio fuels, Turbulent flow, PIV measurement, Engineering mechanics - Fluid mechanics, Teknisk mekanik - Strömningsmekanik
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-18247 (URN)7990f6a9-c7fb-4bab-a530-5cf6d1000050 (Local ID)978-91-7439-836-6 (ISBN)978-91-7439-837-3 (ISBN)7990f6a9-c7fb-4bab-a530-5cf6d1000050 (Archive number)7990f6a9-c7fb-4bab-a530-5cf6d1000050 (OAI)
Note
Godkänd; 2014; 20140108 (ammhaz); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Ammar Hazim Saber Ämne: Strömningslära/Fluid Mechanics Uppsats: Transport of Particles in Turbulent Flow with Application to Bio-Fuels Examinator: Professor Staffan Lundström, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Diskutant: PhD, Managing Director Magnus Marklund, Energitekniskt Centrum i Piteå Tid: Torsdag den 30 januari 2014 kl 10.00 Plats: E231, Luleå tekniska universitetAvailable from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
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