In this study, a continuous and airtight twinspiral dryer was developed in accordance with the characteristics and challenges in the process of disposing polysilicon slurry. Computational fluid dynamics(CFD)simulation...In this study, a continuous and airtight twinspiral dryer was developed in accordance with the characteristics and challenges in the process of disposing polysilicon slurry. Computational fluid dynamics(CFD)simulations were used to investigate the flow field in the rotating twin-spiral continuous dryer and an original discrete phase model was also elaborated to compare with the cold-modeling experimental results. The corresponding flow field was obtained using the available inlet velocity of 0.05-0.3 m/s and the rotational speed of the inner cone of 12-44 r/min, the residence time distribution, and tracked particles trajectory. Results showed that the residence time of the tracer particles in the cone cylinder was about 15.8-25.4% of the time spent out of it, and the particle's residence time was much shorter in contrast to the rotational speed and inlet velocity. The external ribbon had a larger influence on the fluid, thereby leading to a larger velocity in the region outside the cone compared to that in the region inside the cone. In addition, the appearance of the vortex and boundary layer separation at the back of the ribbon and the spoke bar had secondary diversion effects on the fluid. Furthermore, the inlet velocity had little influence on the flow field while the rotational speed of the cone greatly affected the flow field. Hence, the CFD simulations showed good agreement with the experimental results.展开更多
In order to obtain accurate contact parameters of a particulate material in residual film mixture collected by cotton field machine in Xinjiang,the angle of repose test and inclined plane test were carried out.In the ...In order to obtain accurate contact parameters of a particulate material in residual film mixture collected by cotton field machine in Xinjiang,the angle of repose test and inclined plane test were carried out.In the tests,the angles of repose of the particulate material with the water content of(6.26±1.5)%and(14.1±2.1)%were measured respectively,as well as the static sliding friction angle between the particulate material and the residual film.At the same time,the EDEM software was used to calibrate the coefficient of restitution,static friction coefficient and dynamic friction coefficient between the material and the film.Then,the second-order response model between contact parameters and the angle of repose and static sliding friction angle was constructed.In addition,the optimal contact parameters between the granular materials and the mulch were obtained by fitting the physical test data.The results indicated that the errors between the physical test results and the numerical simulation results are small.It was proved that the second-order response model could predict the repose angle of granular materials and the static sliding friction angle between granular materials and farmland film.This study could provide theoretical support for the subsequent model construction of the residual film mixture collected by the cotton field machine.展开更多
文摘In this study, a continuous and airtight twinspiral dryer was developed in accordance with the characteristics and challenges in the process of disposing polysilicon slurry. Computational fluid dynamics(CFD)simulations were used to investigate the flow field in the rotating twin-spiral continuous dryer and an original discrete phase model was also elaborated to compare with the cold-modeling experimental results. The corresponding flow field was obtained using the available inlet velocity of 0.05-0.3 m/s and the rotational speed of the inner cone of 12-44 r/min, the residence time distribution, and tracked particles trajectory. Results showed that the residence time of the tracer particles in the cone cylinder was about 15.8-25.4% of the time spent out of it, and the particle's residence time was much shorter in contrast to the rotational speed and inlet velocity. The external ribbon had a larger influence on the fluid, thereby leading to a larger velocity in the region outside the cone compared to that in the region inside the cone. In addition, the appearance of the vortex and boundary layer separation at the back of the ribbon and the spoke bar had secondary diversion effects on the fluid. Furthermore, the inlet velocity had little influence on the flow field while the rotational speed of the cone greatly affected the flow field. Hence, the CFD simulations showed good agreement with the experimental results.
基金This paper is carried out with the support of major science and technology project of Xinjiang Production and Construction Corps(2018AA001/04)the key industry innovation development support plan of South Xinjiang(2020DB008).
文摘In order to obtain accurate contact parameters of a particulate material in residual film mixture collected by cotton field machine in Xinjiang,the angle of repose test and inclined plane test were carried out.In the tests,the angles of repose of the particulate material with the water content of(6.26±1.5)%and(14.1±2.1)%were measured respectively,as well as the static sliding friction angle between the particulate material and the residual film.At the same time,the EDEM software was used to calibrate the coefficient of restitution,static friction coefficient and dynamic friction coefficient between the material and the film.Then,the second-order response model between contact parameters and the angle of repose and static sliding friction angle was constructed.In addition,the optimal contact parameters between the granular materials and the mulch were obtained by fitting the physical test data.The results indicated that the errors between the physical test results and the numerical simulation results are small.It was proved that the second-order response model could predict the repose angle of granular materials and the static sliding friction angle between granular materials and farmland film.This study could provide theoretical support for the subsequent model construction of the residual film mixture collected by the cotton field machine.
