In this study,the open-source software MFIX-DEM simulations of a bubbling fluidized bed(BFB)are applied to assess nine drag models according to experimental and direct numerical simulation(DNS)results.The influence of...In this study,the open-source software MFIX-DEM simulations of a bubbling fluidized bed(BFB)are applied to assess nine drag models according to experimental and direct numerical simulation(DNS)results.The influence of superficial gas velocity on gas–solid flow is also examined.The results show that according to the distribution of time-averaged particle axial velocity in y direction,except for Wen–Yu and Tenneti–Garg–Subramaniam(TGS),other drag models are consistent with the experimental and DNS results.For the TGS drag model,the layer-by-layer movement of particles is observed,which indicates the particle velocity is not correctly predicted.The time domain and frequency domain analysis results of pressure drop of each drag model are similar.It is recommended to use the drag model derived from DNS or fine grid computational fluid dynamics–discrete element method(CFD-DEM)data first for CFD-DEM simulations.For the investigated BFB,the superficial gas velocity less than 0.9 m·s^(-1) should be adopted to obtain normal hydrodynamics.展开更多
The development of intensification technology for spouted beds has become a current research focus,and an effective way to improve the efficiency of spouted beds is to reform their structure.Although numerous studies ...The development of intensification technology for spouted beds has become a current research focus,and an effective way to improve the efficiency of spouted beds is to reform their structure.Although numerous studies have been conducted on conventional beds,there are few reviews on the comprehensive application of intensification technology for spouted beds.In this paper,we comprehensively review the role of intensification technology in spouted beds for use in hydrodynamics,drying,desulfurization,pyrolysis,coating,biomass and waste gasification,and biomass drying from the perspective of experiment and simulation.Finally,potential problems and challenges in current spouted-bed research are summarized.展开更多
Diagnosis of malfunction in fluidized beds is always a very difficult problem for a long time in academic circles and industrial circles. In this paper,we use acoustic sensor to measure the passive acoustic emissions ...Diagnosis of malfunction in fluidized beds is always a very difficult problem for a long time in academic circles and industrial circles. In this paper,we use acoustic sensor to measure the passive acoustic emissions (AE) from a bubbling fluidized bed.By comparison between acoustic and pressure signals,we found that acoustic signals are very sensitive to large particles such as agglomeration and particle sintering occurred in the bed and so on.Analysis of AE mechanism shows that AE measurement mainly stems from particle-chamber collisions and friction.AE measurements are completely non-intrusive and are not subject to erosion, corrosion, or plugging.Therefore, study and measurement of AE in different fluidization conditions will provide many new methods and trains of thought for detecting early deterioration of the fluidization quality.展开更多
基金the China-CEEC Joint Higher Education Project(Cultivation Project)(CEEC2021001)Srdjan Beloševic,Aleksandar Milicevic and Ivan Tomanovic acknowledge the financial support by the Ministry of Science,Technological Development and Innovation of the Republic of Serbia(Contract Annex:451-03-47/2023-01/200017).
文摘In this study,the open-source software MFIX-DEM simulations of a bubbling fluidized bed(BFB)are applied to assess nine drag models according to experimental and direct numerical simulation(DNS)results.The influence of superficial gas velocity on gas–solid flow is also examined.The results show that according to the distribution of time-averaged particle axial velocity in y direction,except for Wen–Yu and Tenneti–Garg–Subramaniam(TGS),other drag models are consistent with the experimental and DNS results.For the TGS drag model,the layer-by-layer movement of particles is observed,which indicates the particle velocity is not correctly predicted.The time domain and frequency domain analysis results of pressure drop of each drag model are similar.It is recommended to use the drag model derived from DNS or fine grid computational fluid dynamics–discrete element method(CFD-DEM)data first for CFD-DEM simulations.For the investigated BFB,the superficial gas velocity less than 0.9 m·s^(-1) should be adopted to obtain normal hydrodynamics.
基金supported by the National Natural Science Foundation of China(22178286)Shaanxi Qin Chuangyuan“scientist and engineer”team construction project(2022KXJ-041).
文摘The development of intensification technology for spouted beds has become a current research focus,and an effective way to improve the efficiency of spouted beds is to reform their structure.Although numerous studies have been conducted on conventional beds,there are few reviews on the comprehensive application of intensification technology for spouted beds.In this paper,we comprehensively review the role of intensification technology in spouted beds for use in hydrodynamics,drying,desulfurization,pyrolysis,coating,biomass and waste gasification,and biomass drying from the perspective of experiment and simulation.Finally,potential problems and challenges in current spouted-bed research are summarized.
文摘Diagnosis of malfunction in fluidized beds is always a very difficult problem for a long time in academic circles and industrial circles. In this paper,we use acoustic sensor to measure the passive acoustic emissions (AE) from a bubbling fluidized bed.By comparison between acoustic and pressure signals,we found that acoustic signals are very sensitive to large particles such as agglomeration and particle sintering occurred in the bed and so on.Analysis of AE mechanism shows that AE measurement mainly stems from particle-chamber collisions and friction.AE measurements are completely non-intrusive and are not subject to erosion, corrosion, or plugging.Therefore, study and measurement of AE in different fluidization conditions will provide many new methods and trains of thought for detecting early deterioration of the fluidization quality.
