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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Hydrodynamics,Fluidized bed,high temperature,Radioactive particle tracking
- چکیده:
- چکیده انگلیسی: Effect of temperature on hydrodynamics of bubbling gas-solid fluidized beds was investigated. Experiments were carried out in the range of 25-600 ºC and different superficial gas velocities in the range of 0.17-0.78 m/s with sand particles. Time-position trajectory of particles was obtained by radioactive particle tracking technique. These data were used for determination of mean velocities of upward-moving (including bubble wake and ascending clusters) and downward-moving (descending clusters) particles. It was found that the upward velocity increases by increasing temperature up to 300 ºC, however, it decreases by further increase in temperature. Due to the wall effect, there is no significant change in the mean velocity of downward-moving clusters. The change in hydrodynamic parameters with temperature can be a consequence of changing physical properties of the bed which have been represented by Reynolds number in this study.
- انتشار مقاله: 28-01-1388
- نویسندگان: Shabnam Sanaei,Navid Mostoufi,Ramin Radmanesh,Rahmat Sotudeh Gharebagh,Jamal Chaouki
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Fluidized bed,Scale effects,Radioactive Particle Tracking (RPT)
- چکیده:
- چکیده انگلیسی: Effect of scale on the hydrodynamics of gas-solid fluidized beds was investigated in two fluidized beds of 152 mm and 78 mm in diameter. Air at room temperature was used as the fluidizing gas in the bed of sand particles. The Radioactive Particle Tracking (RPT) technique was employed to obtain the instantaneous positions of the particles at every 20 ms of the experiments. These data were used to calculate hydrodynamic parameters, such as mean velocity of upward and downward-moving particles, jump frequency, cycle frequency and axial and radial diffusivities, which are representative of solid mixing and diffusion of particles in the bed. These hydrodynamic parameters were compared in both scales in order to determine the scale effect on the hydrodynamics of the gas-solid fluidized bed. In all cases, it was shown that solid mixing and diffusivity of particles increase by increasing column diameter. The results of this study would help to understand solid mixing which might be critical in industrial fluidized bed reactors.
- انتشار مقاله: 02-02-1387
- نویسندگان: Hamed Bashiri,Navid Mostoufi,Rahmat Sotudeh-Gharebagh,Jamal Chaouki
- مشاهده