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Show A high powered argon-ion based (green light at 514.5nm wavelength), singl&thannel, on-axis back scatter laser Doppler velocimeter (LOY) system (TSI-Model 9600) was used to make the velocity measurements. A counter-type signal processor was used for data processing. The digital output from the counter processor was interfaced to an mM micro-computer for subsequent data handling, see Figure 2. 11.1 Results of Cold Flow Experiments The results obtained from the LOV measurements of particles in the freeboard are presented in Figures 3 through 6. The experiments were carried out under the following conditions: Fluidization velocity: Bed height: Bed material: 24.5 cm/s 7cm Sand dp= l00Jlm Measurement point in the freeboard: Z = 11 cm on the symmetry axis The results obtained from the experiments with no secondary flow introduced are presented in Figure 3. The axial velocity profile follows a parabolic pattern up to the column wall. It is seen from the same figure that a strong radial component for the ejected particle exists. Compared to the other CUlVes presented in Figures 4,5 and 6 for swirl numbers 0.4, 0.6, and 0.8, respectively, the effect of tangential component can be clearly seen. All three velocity components indicate the strong presence of the vortexing motion with ascending and descending zones. The results verify the positive effects of the secondarv air iniection. .!!! ! :£ c.. > u u .... u /--. . . u ... r-- • ,.. u • I . ~ I • -;-- • / • -- .- .............. . ~ ~ ~ . -.- - . .- .............. " •• I •• us r(mm) SN • 0.0. Uf· 2.05 anls. Z • 11 em Figure 3. Variation of upward particle velocity in the radial direction 5 |
