On the Nonuniformity in Fluidized Bed

Mean (μc) and variance (σ) of local particle concentration in fluidized bed were measured by capacitance probe method using integrator and vacuum tube thermocouple. Particle concentration in bubble and dense phases (cb and cd), rise velocity of bubble (ub), bubble thickness (y) and its frequency (f) were also measured from the signal current recorded on oscillograms. The effects of fluidizing conditions on μc and σ were studied. In the bulk of bed, μc remains at a value fixed by the fluidizing conditions. It decreases with air velocity. σ, on the other hand, increases with probe level up to considerably higher portion of bed and there arrives at a constant value which increases with bed height and air velocity. The following equation was introduced to represent μc by the fluidizing characteristics. μc=yf/ubcb+(1-yf/ub)cd μc calculated by this equation coincides well with the measured μc. A regression equation of σ upon fluidizing characteristics, σ=0.72{yf/ub(1-yf/ub)}⁰.⁴⁶(cd-cb)².⁸⁹ was obtained, and the statistical analyses on this equation revealed that σ changes chiefly with (cd-cb), and accordingly, σ represents the nonuniformity in fluidized bed mainly in the form of particle concentration difference between bubble and dense phases

Rate of Heat Transfer between a Fluidized Bed and the Tube Wall at Higher Temperature

The heat transfer coefficient between a fluidized bed and the tube wall, hw, was measured in the temperature range of 500° to 800°C. Quartz and fused alumina particles were fluidized in the air stream. The coefficient hw was obtained between 70 and 800 kcal/m²·hr·°C. It increases with the flow rate of air. The effects of bed temperature and heat content and size of the particles on hw were imperceptible. By comparing the heat transfer coefficients obtained in this work with those at lower temperatures below 200°C, the difference between both coefficients was not significant

リュウドウソウ ニ オケル オウテッコウ オヨビ セッカイセキ ノ ネツ ブンカイ ハンノウ ニ カンスル ケンキュウ

京都大学0048新制・論文博士工学博士乙第1651号論工博第362号新制||工||164(附属図書館)UT51-45-X81(主査)教授 近藤 良夫, 教授 盛 利貞, 教授 森山 徐一郎学位規則第5条第2項該当Kyoto UniversityDFA