A novel reactor with two reaction zones is proposed for pyridine synthesis.The flow hydrodynamics were investigated in experiments.Pressure taps and a PV-6D optical fiber were used to measure the pressure fluctuation ...A novel reactor with two reaction zones is proposed for pyridine synthesis.The flow hydrodynamics were investigated in experiments.Pressure taps and a PV-6D optical fiber were used to measure the pressure fluctuation and particle concentration,respectively.Hilbert–Huang analysis was adopted to distinguish the flow patterns through pressure fluctuation.Results show that the flow patterns are bubbling fluidization and fast fluidization in the regions below(reaction zone I)and above(reaction zone II)the nozzles,respectively.The radial distribution of the cluster time fraction was obtained through signal waves of the particle concentration.Analysis of the cluster time fraction revealed two radial distributions.In the region around the nozzles,the cluster time fraction ranged from 0 to 0.2 and concentrated at radial positions r/R=0–1,which resulted from unsymmetrical catalyst feeding.In reaction zone II,the cluster time fraction ranged from 0 to 0.2,and the radial distribution indicated a core–annulus structure.展开更多
A two-streak high-speed photography measuring system is designed, which can successfully record the reactive shock front and the reaction profile within the run distance of shock initiation under two-dimensional shock...A two-streak high-speed photography measuring system is designed, which can successfully record the reactive shock front and the reaction profile within the run distance of shock initiation under two-dimensional shock initiation. The strong reaction delay time and the shape of reaction shock front are determined in the cast composition B (RDX/TNT/60/40). A low level reaction zone has been found and analyzed..展开更多
The two-dimensional cellular detonation propagating in a channel with area-changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Eff...The two-dimensional cellular detonation propagating in a channel with area-changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Effects of the flow ex-pansion and compression on the cellular detonation cell were investigated to illus-trate the mechanism of the transverse wave development and the cellular detona-tion cell evolution. By examining gas composition variations behind the leading shock,the chemical reaction rate,the reaction zone length,and thermodynamic parameters,two kinds of the abnormal detonation waves were identified. To explore their development mechanism,chemical reactions,reflected shocks and rarefac-tion waves were discussed,which interact with each other and affect the cellular detonation in different ways.展开更多
基金The authors gratefully acknowledge financial support from National Natural Science Foundation of Chinaunder GrantNos.91534111.
文摘A novel reactor with two reaction zones is proposed for pyridine synthesis.The flow hydrodynamics were investigated in experiments.Pressure taps and a PV-6D optical fiber were used to measure the pressure fluctuation and particle concentration,respectively.Hilbert–Huang analysis was adopted to distinguish the flow patterns through pressure fluctuation.Results show that the flow patterns are bubbling fluidization and fast fluidization in the regions below(reaction zone I)and above(reaction zone II)the nozzles,respectively.The radial distribution of the cluster time fraction was obtained through signal waves of the particle concentration.Analysis of the cluster time fraction revealed two radial distributions.In the region around the nozzles,the cluster time fraction ranged from 0 to 0.2 and concentrated at radial positions r/R=0–1,which resulted from unsymmetrical catalyst feeding.In reaction zone II,the cluster time fraction ranged from 0 to 0.2,and the radial distribution indicated a core–annulus structure.
文摘A two-streak high-speed photography measuring system is designed, which can successfully record the reactive shock front and the reaction profile within the run distance of shock initiation under two-dimensional shock initiation. The strong reaction delay time and the shape of reaction shock front are determined in the cast composition B (RDX/TNT/60/40). A low level reaction zone has been found and analyzed..
文摘The two-dimensional cellular detonation propagating in a channel with area-changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Effects of the flow ex-pansion and compression on the cellular detonation cell were investigated to illus-trate the mechanism of the transverse wave development and the cellular detona-tion cell evolution. By examining gas composition variations behind the leading shock,the chemical reaction rate,the reaction zone length,and thermodynamic parameters,two kinds of the abnormal detonation waves were identified. To explore their development mechanism,chemical reactions,reflected shocks and rarefac-tion waves were discussed,which interact with each other and affect the cellular detonation in different ways.
