Students and staffPhilanthropyMedia

Experimental burning processes and vortex flame research

Eksperimental burning process and vortex flame research

The main goal of our research is to create and optimize the process of burning within a vortex flame by doing detailed research of vortex flow creation and  related burnt product recirculation. The recirculation greatly influences mixing speed of before divided flows with axial fuel and vortex air input, providing opportunity to control the burning dynamics and the radial and axial temperature and composition profiles in the field of burning flame,  allowing for a change in the amount of harmful emisions (NOx, CO), and soot nanoparticle creation within the flame and their emisions within the environment.  For vortex flame dynamics control within experimental research an external electric field and flame interaction is used by means of electric force (F=qE) changing velocity distribution in the vortex flow, thus substantially reducing or intensifying formation of recirculation flow within the field where the flame is created. The research results (1st image) prove that by using external magnetic field it is possible to purposefully change the shape of the flame, modifying its burning length, width and with that axial and radial temperature and composition distribution within the field of burning, which changes significantly when the axially placed electrodes potential and polarity is changed.    1st image. Width and length changes to the vortex flame caused by external electric fields while changing axially placed electrodes potential and polarity: 1. U=0; 2. U=+0.3 kV; 3. U=+1.8 kV; 4. U=-1.8 kV     Experimental apparatus: Draft of the experimental apparatus is shown in the 2nd image. Main junctions of the apparatus - vortex flame spawning burner, segmented cooling channel and axially placed electrode. Before undisturbed vortex flames fuel feed in burner is axial, but air feed- tangential. For fuel feed a nozzle is used in the burner. Whose inner diameter is 20mm, but for air feed a ring with 8 tangential openings (inner diameters 3mm) is used, placed in the base of the burner. Speed of Air feed is changed between 10 l/min and 20l/min, but fuel (propane) intake is from 0.4 l/min to 1 l/min, changing vortex flames flow from 0.6 m/s to 1.26 m/s, but tangential velocity between 3,5 and 7 m/s. Air flows vortex number S burners in output is relatively high in these conditions and reaches S≈5,6. Air abundances coefficient within burner output is variable between a=0.7 and a=1.44 For the burning field, external electric field is placed between, axially placed electrode, burners surface and channels walls. Electrodes potential is variable in the ranges of -3kV to +3kV, limiting ions current in the flame up to 200mkA   2nd. image.  Digital image of the experimental apparatus (a) and schematic (b): 1- axially placed electrode; 2- water cooled channel sections; 3- opening for placement of flames diagnostics; 4- air supply nozzle; 5- propane supply; 6- burners casing; 7- recirculations zones creation at burners output and recirculations zones schematic (c)
Flame vortex flow main parameter measuring methods:
  • Pt/Pt-Rh(10%) thermopairs are used for measurement of flames temperatures radial and axial distribution. PC-20TR is used for date collection and processing.
  • For Flames composition radial and axial distributions measurements locally taken gas samples are used with spectral analysis methods. For the Infrared part of the spectrum measurements of the flame, spektrofotometre Specord is used, which determines changes of flames composition (CO, CO2, CH4, C2H2 un C2H4) in different stages of the burning process. Spectrumfotometer DFS-8 is used for visible light and ultraviolet light measurement of the flames composition.
  • Pito tubes and laser Dopler anemometer (ILA) is used for flow dynamics (flames speed axial and tangential distribution) research  
  • Heat transfer processes within channels in different flame development stages are controlled using calorimetric water flow measurements, by registering cooling water temperature margins in deffrent sections using PC-20TR  
  • Using gravimetrical measurements, soot particle creation is controlled within the flame. Soot particle and structure alterations according to flames length is determined using electron microskope and x-ray diffraction methods. 
  • Burning output compositions (NOx, CO2, CO, O2) radial and axial distribution changes are controlled using gas analyzer Testo 350-XL 
Electric field and flame interaction research includes:
  • Experimental research of fields influence to processes of heat and mass transfer within a flame in different burning process development stages of a flame;
  • Experimental research of fields influence to local flame composition alterations, evaluating electric fields influence on flames composition radial and axial distributions alterations.
  • Experimental research of fields influence to local burning process speed and flames temperature alterations, evaluating electric fields influence on flames composition radial and axial distributions alterations.
  • Experimental research of fields influence to global warming causing CO2 causing NOx creation within the burning area.
  • Experimental research of fields influence to soot particle development.
  • Evaluation of field influence on carbon gathering and seperation.

Main publishings:
  • M. Zake, I. Barmina, A. Desnickis, Electric control of combustion dynamic and pollutant emission from the swirl stabilized premixed combustion, CHISA-2006-17th International Congress of Chemical and Process Engineering, Praha, August 2006, CD-ROM with full texts, P5.96, p. 1-13.
  • I. Barmina, A. Desņickis, A. Meijere, M. Zake, Active Electric Control of Emissions from the Swirling Combustion, Kijev- NATO, May, 2006, pp.1-8.
  • M. Zaķe, I. Barmina, D. Turlajs, M. Lubāne, A. Krūmiņa, Swirling Flame. Part 2. Electric Field Effect on the Soot Formation and Greenhouse Emissions. Magnetohydrodynamics, 2004, Vol. 40, No 2, p.183-202.
  • M. Zaķe, I. Barmina, M. Lubāne, Swirling flame. Part 1. Experimental Study of the Effect of Stage Combustion on Soot Formation and Carbon Sequestration from the Nonpremixed Swirling Flame. Magnetohydrodynamics, 2004, Vol. 40, No 2, p.161-181.