| OCR Text |
Show Measurement and Interpretation -12 - of Flames Issued from a Generic Multi-Fuel Burner - _ ~ _ .J2-1l -~r . -~r m· l =m· · f(x)·-y2·1l=m . ·--e 2 =m .. e 2 I, I I .J2. 1l I IFRF-~ A particle of the same size is then injected with the complementary mass, i.e., mi,2 =mi·(l- f(x)·~2·1l) with the value of x being determined from the equation of the normal distribution with a random selection of the sign of (x - x). A 3-D calculation requires that a tangential component be calculated in a similar manner. To date the spray combustion calculations have been performed in 2-D geometry to minimize the computation overhead. The rapid mixing of fuel vapor in the swirling flow is expected to minimize the error introduced by this simplification. 3.3.3. Velocity Distnoutions. The distribution of velocity components remains to be detennined. The measured mean values are shown in figure 3.4. As expected the tangential component is nearly zero everywhere and can be neglected. The distnbution of velocity vectors is shown to resemble a Gaussian distribution centered around the mean-spray half-angle_ The velocity magnitude, V ,at the nozzle exit is determined by extrapolating the velocity magnitude at the position of maximum event rate at each downstream location as shown in Fig. 3.5 for the four detailed cases which were measured. The center of the spray cone was selected since these droplets are the least affected by drag forces. The extrapolation of these velocities should be representative of the droplet velocities at the nozzle exit. The velocity distnbution is then described by using the angle a obtained from the procedure described above used in determining the radial variation in normalized number flux: As with the mass-fluxes, incorporation into a 3-D calculation will require that the tangential velocity components be represented. |
