Flow and Combustion

About us

Flow and Combustion, part of the research group Thermotech, studies selected physical flow phenomena
with application to innovative burner technologies. Two particular burner topologies are of interest:

• Annular Jets: Swirling and Non-Swirling
• Perforated Plates

Next to this the group also has experience in sudden expansion flows.

Our approach is theoretical, numerical as well as experimental, for which we have state-of-the-art measurement equipment and experimental setups.

Keywords: flow instabilities, swirling flows, vortex breakdown and precession, reattachment flows

Gallery

• Some pictures out of our laboratory
  

Jet instability	Artistic interpretation of vortices	Typical lab setup	Particle Image Velocimetry

• Movies

Annular jet flame	LDA setup	Colormap of transient annular jet velocity

Current research

Annular Jets: Swirling and Non-Swirling Swirling flows are widespread in nature as well as in industrial applications. Examples of natural swirling flows are tornado's. Swirling flows are also used in many engineering applications, such as for instance in combustion. The effects of swirl are flame stabilisation and a more intense mixing of air and fuel. For this reason this research focusses a swirling flows in a geometry resembling a combustor. Only the cold swirling flow is studied (flow without combustion) since understanding this flow is crucial in understanding the flow with combustion. The nozzles are specially designed to give hysteresis between the increasing and subsequent decreasing of swirl. In addition to the experiments, the observed phenomena are also explained in numerical studies. Also a nozzle is designed which allows the transition between flow patterns without the use of swirl. With this nozzle it is possible to switch the flow pattern by making use of cross-injection of small radial jets. This new method of flow control allows a transition with advantages compared to the traditional methods.

Perforated Plate Flow with Application to Burners The use of perforated plate burners in modern residential heating devices is widespread. The major advantage of these burners is that they have low NOx-emissions. However their application is hindered by a very intense sound production making economical usage not feasible. In order to counteract this problem we study its origin, which is a flow instability, and try to suppress it by means of innovative damping techniques. Sudden Expansion Flows Sudden expansion flows are encountered in a variety of engineering applications, such as combustion chambers, chemical reactors, heat exchangers, ... In a sudden expansion an inlet pipe with small diameter leads to an outlet pipe with a large one through a sudden enlargement in pipe diameter. The flow is unable to follow the sudden enlargement and will detach at the sudden expansion. After some length downstream, called the reattachment length, the flow attaches to the outlet pipe. This reattachment length is highly dependent on the inlet conditions of the flow and the expansion ratio. Due to the importance of swirl in a number of sudden expansion flows, this study investigates the influence of swirl on the reattachment length in order to have a better understanding of the flow field in for instance combustion chambers or chemical reactors.

Experimental measurement equipment

Our laboratory is equipped with a Laser Doppler Anemometry and a Particle Image Velocimetry measurement device.

Publications

Vanierschot, M., Persoons, T., Van den Bulck, E. (2009). An Eulerian time filtering technique to study large-scale transient flow phenomena,. Experiments in Fluids, Volume: 47, Issue: 4-5, Pages: 613-626 Published: OCT 2009, doi

Vanierschot, M; Persoons, T; Van den Bulck, E, A new method for annular jet control based on cross-flow injection, Physics of Fluids Volume: 21 Issue: 2, Number: 025103, 2009, doi

Vanierschot M., Van den Bulck E., ‘Computation of a drastic flow pattern change in an annular swirling jet caused by a small change in inlet swirl’, International Journal for Numerical Methods in Fluids, Vol: 59, Issue: 5, pp. 577-592, 2009, doi

Vanierschot M, Van den Bulck E, Planar Pressure Field Determination in the Initial Merging Zone of an Annular Swirling Jet Based on Stereo-PIV Measurements, Sensors 8, 7596-7608; 2008, doi

Vanierschot M, Van den Bulck E, Influence of swirl on the initial merging zone of a turbulent annular jet, Physics of Fluids, 20, 105104, 2008, doi

Vanierschot M, Van den Bulck E, The influence of swirl on the reattachment length in an abrupt axisymmetric expansion, International Journal of Heat and Fluid Flow, Vol. 29, 75-82, 2008, doi

Vanierschot M, Van den Bulck E, Influence of the nozzle geometry on the hysteresis of annular swirling jets, Combustion Science and Technology 179 (8): 1451-1466 2007, doi

Vanierschot M, Van den Bulck E, Hysteresis in flow patterns in annular swirling jets,Experimental Thermal and Fluid Science, Volume 31, Issue 6, Pages 513-524, May 2007, doi

Vanierschot M, Van den Bulck E, Numerical study of hysteresis in annular swirling jets with a stepped-conical nozzle, International Journal for Numerical Methods in Fluids 54 (3): 313-324, 2007, doi

More...

Van den Bulck E, The nonlinear increase of Nusselt number with friction factor in fully developed laminar duct flow, Journal of Heat Transfer-Transactions of the ASME 126 (5): 840-842 OCT 2004, doi

Vanoverberghe K, Van den Bulck E, Tummers M, Flow structure of lifted swirling jet flames, Flow Turbulence and Combustion 73 (1): 25-47 JUL 2004

Helsen L, Van den Bulck E, Van Bael MK, et al., Thermal behaviour of arsenic oxides (As2O5 and As2O3) and the influence of reducing agents (glucose and activated carbon)
Thermochimica Acta 414 (2): 145-153 MAY 27 2004, doi

Helsen L, Van den Bulck E, Metal retention in the solid residue after low-temperature pyrolysis of chromated copper arsenate (CCA)-treated wood, Environ Eng Sci 20 (6): 569-580 nov-dec 2003

Helsen L, Van den Bulck E, Cooreman H, et al., Development of a sampling train for arsenic in pyrolysis vapours resulting from pyrolysis of arsenic containing wood waste, J Environ Monitor 5 (5): 758-765 SEP 2003, doi

Vanoverberghe K, Van den Bulck EV, Tummers MJ, Confined annular swirling jet combustion, Combust Sci Technol, 175 (3): 545-578, 2003, doi

Vanoverberghe K, Van den Bulck EV, Tummers MJ, Hubner WA, Multiflame patterns in swirl-driven partially premixed natural gas combustion, J ENG GAS TURB POWER 125 (1): 40-45 JAN 2003, doi

Helsen LML, Van den Bulck EVM , Study of a new macro-particle model for the low-temperature pyrolysis of dried wood chips, HEAT MASS TRANSFER 38 (1-2): 165-181 NOV 2001

Mufuta JM, Van den Bulck E , Modelling of the mass flow distribution around an array of rectangular blocks in-line arranged and simulating the cross-section of a winding disc-type transformer, APPL THERM ENG 21 (7): 731-749 MAY 2001

Helsen L, Van den Bulck E , Metal behavior during the low-temperature pyrolysis of chromated copper arsenate-treated wood waste, ENVIRON SCI TECHNOL 34 (14): 2931-2938 JUL 15 2000

Mufuta JM, Van den Bulck E , Modelling of the mixed convection in the windings of a disc-type power transformer, APPL THERM ENG 20 (5): 417-437 APR 2000

Helsen L, Van den Bulck E , Kinetics of the low-temperature pyrolysis of chromated copper arsenate-treated wood, J ANAL APPL PYROL 53 (1): 51-79 JAN 2000

Vanormelingen J, Van den Bulck E, Scalar transport in plane mixing layers HEAT MASS TRANSFER 35 (5): 383-390 OCT 1999

Vanormelingen J, Van den Bulck E , Optimization of overfire air systems of cylindrical combustion chambers, ENVIRON ENG SCI 16 (5): 353-373 SEP-OCT 1999

Helsen L, Van den Bulck E, Mullens S, et al. , Low-temperature pyrolysis of CCA-treated wood: thermogravimetric analysis, J ANAL APPL PYROL 52 (1): 65-86 SEP 1999

Helsen L, Van den Bulck E, Hery JS, Total recycling of CCA treated wood waste by low-temperature pyrolysis, WASTE MANAGE 18 (6-8): 571-578 1998

Zuo B, Bulck EVDB , The modeling, scale and NOx characteristics of pre-vaporized, premixed fuel oil burner combustions, COMBUST SCI TECHNOL 137 (1-6): 149-169 1998

 Helsen L, Van den Bulck E , The microdistribution of copper, chromium and arsenic in CCA treated wood and its pyrolysis residue using energy dispersive X-ray analysis in scanning electron microscopy, HOLZFORSCHUNG 52 (6): 607-614 1998

Zuo BF, Van den Bulck E , A quasi-global mechanism for oxidation of fuel oil and the laminar flame data library, COMBUST FLAME 113 (4): 615-619 JUN 1998

Zuo BF, Van den Bulck E, Fuel oil evaporation in swirling hot gas streams, Int J Heat Mass Tran 41 (12): 1807-1820 JUN 1998

Wardenier K, Vandenbulck E, Steady-state waste combustion and air flow optimization in a field scale rotary kiln, ENVIRON ENG SCI 14 (1): 43-54 1997

Helsen L, Van den Bulck E, Van den Broeck K, C. Vandecasteele, Low-temperature pyrolysis of CCA-treated wood waste: Chemical determination and statistical analysis of metal input and output; Mass balances, WASTE MANAGE 17 (1): 79-86 1997

VandenBroeck K, Helsen L, Vandecasteele C, Van den Bulck E, Determination and characterisation of copper, chromium and arsenic in chromated copper arsenate (CCA) treated wood and its pyrolysis residues by inductively coupled plasma mass spectrometry, ANALYST 122 (7): 695-700 JUL 1997.

Vanhoute U, Vandenbulck E, Modeling chiller performance using simultaneous equation-solving procedures, INT J REFRIG 17 (3): 191-198 MAR 1994

Vandenbulck E, Optimal-design of cross-flow heat-exchangers
J HEAT TRANS-T ASME 113 (2): 341-347 MAY 1991

Vandenbulck E, Transient heat and mass-transfer in laminar-flow forced-convection in ducts
INT J HEAT MASS TRAN 34 (4-5): 1249-1258 APR-MAY 1991

Vandenbulck E, Isotherm correlation for water-vapor on regular-density silica-gel, CHEM ENG SCI 45 (5): 1425-1429 1990

Vandenbulck E, Klein SA , A single-blow test procedure for compact heat and mass exchangers
J HEAT TRANS-T ASME 112 (2): 317-322 MAY 1990

Vandenbulck E, Mitchell JW, Klein SA , 2nd Law analysis of solid desiccant rotary dehumidifiers
J SOL ENERG-T ASME 110 (1): 2-9 FEB 1988

Vandenbulck E, Mitchell JW, Klein SA, The use of dehumidifiers in desiccant cooling and dehumidification systems, J HEAT TRANS-T ASME 108 (3): 684-692 AUG 1986

Vandenbulck E, Mitchell JW, Klein SA, Design theory for rotary heat and mass exchangers .1. Wave analysis of rotary heat and mass exchangers with infinite transfer-coefficients, Int J Heat Mass Tran 28 (8): 1575-1586 1985

Vandenbulck E, Mitchell JW, Klein SA, Design theory for rotary heat and mass exchangers .2. Effectiveness-number-of-transfer-units method for rotary heat and mass exchangers, INT J HEAT MASS TRAN 28 (8): 1587-1595 1985