Fundamental bubbling characteristics in a rotating fluidized bed: Modeling and measurement of bubble size
Modeling and measurement of bubble size in a rotating fluidized bed (RFB) were conducted. The model for predicting the bubble growth in RFB has been proposed based on the following concepts: (i) local centrifugal acceleration and excess gas velocity are considered as the parameters in the radial direction, and (ii) bubble volume flow locally changes depending on the radial distance. Bubbling behaviors were also experimentally observed by means of a high-sped video camera. Bubble sizes were measured using an image analysis technique, and the measured bubble sizes were compared with the estimated values by our proposed model and the available one for a conventional fluidized bed. The estimated bubble sizes by our proposed model showed good agreement with the measured ones, while the predicted ones by the model for conventional fluidized bed underestimated. The validity of our proposed concepts for modeling of bubble growth in RFB was confirmed.
On partial fluidization in rotating fluidized beds
In a rotating fluidized bed, unlike in a conventional fluidized bed, the granules are fluidized layer by layer from the (inner) free surface outward at increasing radius as the gas velocity is increased. This is a very significant and interesting phenomenon and is extremely important in the design of these fluidized beds. The phenomenon was first suggested in a theoretical analysis and recently verified experimentally in the authors' laboratory. However, in the first paper, the equations presented are too cumbersome and the influence of bed thickness is not clearly stated. In this note the authors present simplified equations, based on that paper, for the pressure drop and the minimum fluidizing velocities in a rotating fluidized bed. Experimental data are also shown and compared with the theoretical model, and the effect of bed thickness is shown. Furthermore, an explanation for the observation of a maximum in the pressure drop vs. velocity curve instead of the plateau derived by Chen is proposed.
The Meaning of Wisdom in James: Examination of a Hypothesis
The following essay is an attempt to examine the manner in which the writer of the Epistle of James uses the concept of Wisdom; and to study the suggestion that the way in which he uses it is more or less interchangeable with that in which other writers of the New Testament use the concept of the Holy Spirit.