Particle-scale study of gas-solid flows in a bubbling fluidised bed: Effect of drag force and collision models

2021 ◽  
Vol 384 ◽  
pp. 353-367
Author(s):  
Tianyu Wang ◽  
Shuai Wang ◽  
Yansong Shen
2020 ◽  
Vol 22 (4) ◽  
pp. 1047-1060
Author(s):  
S. Shadmani ◽  
S. M. Mousavi Nainiyan ◽  
R. Ghasemiasl ◽  
M. Mirzaei ◽  
S. G. Pouryoussefi

AbstractAhmed Body is a standard and simplified shape of a road vehicle that's rear part has an important role in flow structure and it's drag force. In this paper flow control around the Ahmed body with the rear slant angle of 25° studied by using the plasma actuator system situated in middle of the rear slant surface. Experiments conducted in a wind tunnel in two free stream velocities of U = 10m/s and U = 20m/s using steady and unsteady excitations. Pressure distribution and total drag force were measured and smoke flow visualization carried out in this study. The results showed that at U = 10m/s using plasma actuator suppress the separated flow over the rear slant slightly and be effective on pressure distribution. Also, total drag force reduces in steady and unsteady excitations for 3.65% and 2.44%, respectively. At U = 20m/s, using plasma actuator had no serious effect on the pressure distribution and total drag force.


Author(s):  
S. M. FROLOV ◽  
◽  
S. V. Platonov ◽  
K. A. AVDEEV ◽  
V. S. AKSENOV ◽  
...  

To reduce the hydrodynamic drag force to the movement of the boat, an artificial gas cavity is organized under its bottom. Such a cavity partially insulates the bottom from direct contact with water and provides “gas lubrication” by means of forced supply of atmospheric air or exhaust gases from the main propulsion system. A proper longitudinal and transverse shaping of the gas cavity can significantly (by 20%-30%) reduce the hydrodynamic drag of the boat at low (less than 3%) consumption of the propulsion system power for gas supply.


2016 ◽  
pp. 86-90
Author(s):  
Gerald Caspers ◽  
Klaus Nammert ◽  
Holger Fersterra ◽  
Hartmut Hafemann

Fluidised-bed steam dryers have been in use for industrial-scale drying of pressed beet pulp for more than 20 years. This highly energy-efficient process can be considered to be state of the art in the industry. Scientific laboratory and pilot-plant testing have provided the basis for a detailed description of the principles of fluidisation and drying in superheated water vapour. Advances in production data acquisition, in particular regarding the options for the real-time presentation and evaluation of high-resolution operating data (Industry 4.0), have opened up new potentials for optimisation of the drying process in fluidised-bed steam dryers. By analysing and interpreting sequences of events, or simultaneous events, it is now possible to analyse process behaviour in great depth. This allows malfunctions to be avoided by improved design or, assisted by suitable measuring and control systems, to be detected at an early stage. Failures can then be prevented altogether by initiating automated countermeasures. On the basis of more recent insights gained from the analysis of faults and disruptions using modern operating data acquisition, BMA’s fluidised-bed steam dryer (WVT) has been subjected to fundamental technological and technical improvements, so it now meets today’s demands for efficiency and reliability. Modifications include the product inlet, the distribution plate and several other parts, in addition to the known and patented PPS (Plug Protection System; EP 2457649 B1), and the patented rotary weir (EP 2146167 B1).


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