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Show I = mixing inside O = mixing outside P = parallel flow (no swirl) R = rotation (swirl) A = rotation made by holes E = rotation made by elements C = ritarion made by cyclon T = toroide burner Fig 1: Classification of industrial burners greater, than that of a burner having a capacity of 20 m3/s but operating with low-speed air (e.g. 50 m/s). It means, that w e won't obtain an unanimous result if w e want to qualify the burner on the basis of its impulse-power. The problem can be eliminated by introducing the specific impulse-power [2]. In case of burners operating with the same fuel the specific impulse-power can concern a unit fuel mass-flow: 1SD > m ^ .> ^ ' • ~ •I' ^ .' •' •"••s j&' -. -m , - « - , xs > «. ^3J " 03 \C Spec. Impulse Power, Ns/g Fig 2: Change of furnace-efficiency as a function of Isp 1.3. Swirl (Rotation) parameter, direction parameter Since the 60's the use of swirl parameter (earlier 3, nowadays S) has been accepted for describing the rotating flames. The swirl parameter is: S = where: M, do I. Mr 2 £ (4) rotation moment, N m , nozzle-diameter, m, axial component of impulse power t seems to be reasonable to use the axial component of 1^ when calculating the value of S too. If the axes of the bumer-nozzles are fitted on the axis of burner in a negative direction (torroid burners), the direction parameter (T) can be used for characterizing the flame-shape: r = (5) 'sp Ns/g (2) where 1, = axial component of impulse-power of elementary jet, N Ip = component of impulse power of elementary jet perpendicular to the axis, N or a unit heat-flow when comparing burners operating with different fuels: »•- Ns/kJ (3) The specific impulse-power obtained such a way makes it possible to compare the mixing effect of burners having different structures, capacity and mixing systems, furthermore it promotes the better knowledge and conscious utilization of the effect of impulse power. According to the researches made by the author the specific impulse power has an optimum value (lo) between 1. 1< I^< 2 0 from the point of view of furnace-efficiency. It means, that the furnace-efficiency decreases in case of using a smaller or greater value of Isp (Fig. 2). The use of I* greater than U improves the uniformity of flue gas temperature further and by this the uniformity of heating in the furnace chamber. 2.0 Description of eiperimental unit The gas-firing experiments have been made on the Department of Combustion Technology by the Independent Research Team N o 19 of Hungarian Academy of Sciences in the furnace shown in Fig. 3. The denomination of the different structural parts of furnace can be seen in this Fig The lining of furnace-chamber is made of fibrous refractory material An insulated calorimeter chamber is connected to the combustion chamber where a water-cooling tube having a hairpin-shape is placed for cooling the waste flue gas A ring water tube is placed around the plate-covering of calorimeter chamber, from which six water cooled probes enter the working chamber of furnace along the wall of furnace-chamber. The axes of probes are parallel with the axis of furnace-chamber. The probes can be pushed into or pulled out of the combustion chamber by means of a movable mechanism serving for this purpose, and by this the temperature of combustion chamber can be controlled. 6-6 air- and gas inlet tubes are placed on the front-part of calorimeter |