Weak axisymmetrical fountains resulting from the injection of a dense fluid upwards into a large container of homogeneous fluid of lower density has been studied numerically in this paper using a time-accurate finite ...Weak axisymmetrical fountains resulting from the injection of a dense fluid upwards into a large container of homogeneous fluid of lower density has been studied numerically in this paper using a time-accurate finite volume scheme. The behaviour of fountains for both the uniform and parabolic profiles of the discharge velocity at the fountain source has been investigated. The evolution of transient fountain flow has been analysed and two distinct stages of evolution have been identified. The time trace of the position of the fountain front has been presented and the initial, temporary and final fountain height and fountain width have been determined.展开更多
The hydrodynamic behaviour of the spouted bed in the pharmaceutical industries has been found to be less addressed.The present paper has focused on the hydrodynamic characteristics of a spouted bed where the Cellets^(...The hydrodynamic behaviour of the spouted bed in the pharmaceutical industries has been found to be less addressed.The present paper has focused on the hydrodynamic characteristics of a spouted bed where the Cellets^(TM)(Ph.Eur./USP)is adopted as the bed material.Experiments are carried out with three different static bed heights(H_(0))of shallow depth(2D_(i)≤H_(0)<3D_(i))using two different particle sizes.The spouted bed employed with D_(i)/D_(0) of 5 has given the experimental information on external spouting(Ues)by mapping the pressure drop,and fountain height(H_(f))against the superficial gas velocity(U_(g))is rep-resented with the image contours,which show the intrinsic behaviour.All the 1000 μm and 700 μm particles have been found to exhibit symmetric and asymmetric spouting.With increasing U_(g),the fully suspended particles are limited to a certain height in the freeboard region due to the gas-solid cross-flow,which implies the clusters have identified with the image processing method.展开更多
文摘Weak axisymmetrical fountains resulting from the injection of a dense fluid upwards into a large container of homogeneous fluid of lower density has been studied numerically in this paper using a time-accurate finite volume scheme. The behaviour of fountains for both the uniform and parabolic profiles of the discharge velocity at the fountain source has been investigated. The evolution of transient fountain flow has been analysed and two distinct stages of evolution have been identified. The time trace of the position of the fountain front has been presented and the initial, temporary and final fountain height and fountain width have been determined.
文摘The hydrodynamic behaviour of the spouted bed in the pharmaceutical industries has been found to be less addressed.The present paper has focused on the hydrodynamic characteristics of a spouted bed where the Cellets^(TM)(Ph.Eur./USP)is adopted as the bed material.Experiments are carried out with three different static bed heights(H_(0))of shallow depth(2D_(i)≤H_(0)<3D_(i))using two different particle sizes.The spouted bed employed with D_(i)/D_(0) of 5 has given the experimental information on external spouting(Ues)by mapping the pressure drop,and fountain height(H_(f))against the superficial gas velocity(U_(g))is rep-resented with the image contours,which show the intrinsic behaviour.All the 1000 μm and 700 μm particles have been found to exhibit symmetric and asymmetric spouting.With increasing U_(g),the fully suspended particles are limited to a certain height in the freeboard region due to the gas-solid cross-flow,which implies the clusters have identified with the image processing method.
