In this paper, an evolutionary recursive Bayesian estimation algorithm is presented, which incorporates the latest observation with a new proposal distribution, and the posterior state density is represented by a Gaus...In this paper, an evolutionary recursive Bayesian estimation algorithm is presented, which incorporates the latest observation with a new proposal distribution, and the posterior state density is represented by a Gaussian mixture model that is recovered from the weighted particle set of the measurement update step by means of a weighted expectation-maximization algorithm. This step replaces the resampling stage needed by most particle filters and relieves the effect caused by sample impoverishment. A nonlinear tracking problem shows that this new approach outperforms other related particle filters.展开更多
Based on aphid wax-honeydew marble and the hydrophobic wax structure of lotus and its derived applications with superareophilic and superhydrophobic properties,edible carnauba wax and beeswax particles were mixed and ...Based on aphid wax-honeydew marble and the hydrophobic wax structure of lotus and its derived applications with superareophilic and superhydrophobic properties,edible carnauba wax and beeswax particles were mixed and utilized to mimic lotus wax and wrap liquid,thus forming liquid marbles(LMs).Through the utilization of continuous production system(CPS),wax as an interfacial surfactant,water and solid,air-phase or mixed-phase marble content was produced.The edible liquid marble(ELM)could encapsulate water and food droplets.Edible solid marble(ESM)and edible solid hollow marbles(ESHMs)could be fabricated by applying pectin or syrup.Moreover,through the heating of wax powders with different melting temperatures,stable tablets and hollow capsules could be produced.The wax powder as interfacial surfactant could firmly bind with pectin through hydrogen bonds on ESM.The edible LMs can therefore be applied for residue reduction,corrosion reduction,biohazard prevention and cleaning in the food industry.The other phase LMs could act as novel tools in the pharmaceutical and food industries with the above-mentioned water transport,preservation,sustained releasing and selective releasing abilities.展开更多
In this work, a discrete particle model （DPM） was applied to investigate the dynamic characteristics in a gas-solid bubbling fluidized bed of binary solid particles. The solid phase was simulated by the hard- sphere...In this work, a discrete particle model （DPM） was applied to investigate the dynamic characteristics in a gas-solid bubbling fluidized bed of binary solid particles. The solid phase was simulated by the hard- sphere discrete particle model. The large eddy simulation （LES） method was used to simulate the gas phase. To improve the accuracy of the simulation, an improved sub-grid scale （SGS） model in the LES method was also applied. The mutative Smagorinsky constant case was compared with the previously published experimental data. The simulation by the mutative Smagorinsky constant model exhibited better agreement with the experimental data than that by the common invariant Smagorinsky constant model. Various restitution coefficients and different compositions of binary solids were investigated to determine their influences on the rotation characteristics and granular temperatures of the particles. The particle translational and rotational characteristic distributions were related to certain simulation parameters.展开更多
This study presents a three-dimensional numerical study of the mixing and segregation of binary particle mixtures in a two-jet spout fluidized bed based on an Eulerian-Eulerian three-fluid model. Initially, the partic...This study presents a three-dimensional numerical study of the mixing and segregation of binary particle mixtures in a two-jet spout fluidized bed based on an Eulerian-Eulerian three-fluid model. Initially, the particle mixtures were premixed and packed in a rectangular fluidized bed. As the calculation began, the gas stream was injected into the bed from the distributor and jet nozzles. The model was validated by comparing the simulated jet penetration depths with corresponding experimental data. The main features of the complex gas-solid flow behaviors and the mechanism of mixing and segregation of the binary mixtures were analyzed, Moreover, further simulations were carried out to evaluate the effects of operating conditions on the mixing and segregation of binary particle mixtures. The results illustrate that mixing can be enhanced by increasing the jet velocity or enlarging the difference of initial proportions of binary particle mixtures.展开更多
Coal-direct chemical-looping combustion(CDCLC)is a promising coal combustion technique that provides CO2 capture with a low energy penalty.In this study,we developed a three-dimensional Eulerian-Eulerian multiphase fu...Coal-direct chemical-looping combustion(CDCLC)is a promising coal combustion technique that provides CO2 capture with a low energy penalty.In this study,we developed a three-dimensional Eulerian-Eulerian multiphase full-loop model for simulating the circulation and separation of binary particle mixtures in a novel high-flux CDCLC system.This model comprised a high-flux circulating fluidized bed as the fuel reactor(FR),a counter-flow moving bed as the air reactor(AR),a high-flux carbon stripper,two downcomers,and two J-valves.This model predicted the main features of complex gas-solid flow behaviors in the system.The simulation results showed that quasi-stable solid circulation in the whole system could be achieved,and the FR,AR,and J-valves operated in a dense suspension upflow regime,a near-plug-flow regime,and a bubbling fluidization regime,respectively.The multiphase flow model of binary particle mixtures was used to predict the mechanisms of directional separation of binary particle mixtures of an oxygen carrier(OC)and coal throughout the system.A decrease in the baffle aspect ratio of the inertial separator improved the coal selective separation efficiency but resulted in a slight decline in the OC selective separation;this is believed to be the result of weakening of particle collisions with the baffle.A higher FR gas velocity had a slightly negative effect on the OC selective separation efficiency,but improved the coal selective separation efficiency;this can be attributed to an increase in the particle-carrying capacity of the gas stream.A decrease in the coal particle size led to better entrainment of the coal particles by the gas stream and this increased the coal selective separation efficiency.In real CDCLC applications,the operating variables for separation of binary particle mixtures should be comprehensively assessed to determine their positive and negative effects on the carbon capture efficiency,OC regeneration efficiency,gas leakage restraint,energy consumption,and fuel conversion.展开更多
The packing densification of binary spherical mixtures under 3D mechanical vibration was studied experimentally. The influences of vibration frequency （ω）, volume fraction of large spheres （XL）, sphere size ratio...The packing densification of binary spherical mixtures under 3D mechanical vibration was studied experimentally. The influences of vibration frequency （ω）, volume fraction of large spheres （XL）, sphere size ratio （r, diameter ratio of small to large spheres）, and container size （D） on the random binary packing density （p） were systematically analyzed. For any given set of conditions, there exist optimal ω and XL to realize the densest random binary packing; too large or small ω and XL is not helpful for densification. The influences of both r and D on p are monotonic; either reducing r or increasing D leads to a high value of p. With all other parameters held constant, the densest random packing occurs when XL is dominant, which is in good agreement with the Furnas relation. Moreover, the highest random binary packing density obtained in our work agrees well with corresponding numerical and analytical results in the literature.展开更多
Particle elongation is an important factor affecting the packing properties of rod-like particles. However, rod-like particles can be easily bent into non-convex shapes, in which the effect of bending should also be o...Particle elongation is an important factor affecting the packing properties of rod-like particles. However, rod-like particles can be easily bent into non-convex shapes, in which the effect of bending should also be of concerned, To explore the shape effects of elongation and bending, together with the size and volume fraction effects on the disordered packing density of mixtures of non-convex particles, binary and polydisperse mixtures of curved spherocylinders are simulated employing sphere assembly models and the relaxation algorithm in the present work. For binary packings with the same volume, curves of the packing density versus volume fraction have good linearity, while densities are plotted as a series of equidistant curves under the condition of the same shape. The independence of size and shape effects on the packing density is verified for mixtures of curved spherocylinders. The explicit formula used to predict the density of binary mixtures, by superposing the two independent functions of the size and shape parameters, is extended to include a non-convex shape factor. A polydisperse packing with the shape factor following a uniform distribution under the condition of the same volume is equivalent to a binary mixture with certain components. The packing density is thus predicted as the mean of maximum and minimum densities employing a weighing method.展开更多
Dry deposited particles, larger than 1.3 μm, were collected under clear, cloudy, and foggy conditions during a cruise, traversing the Yellow Sea and the East China Sea from 23 March to 8 April 2011. In these areas, a...Dry deposited particles, larger than 1.3 μm, were collected under clear, cloudy, and foggy conditions during a cruise, traversing the Yellow Sea and the East China Sea from 23 March to 8 April 2011. In these areas, air masses are influenced by pollution outflows from the Asian continent. The size and elemental composition of dry deposited particles were investigated using a scanning electron microscope. Number-size distributions of these particles were approximately lognormal. Under clear conditions, the mode size was about 5.0 μm, with a mean diameter of 6.9 μm. Under cloudy and foggy conditions, the mean diameters were 5.7 and 6.0 μm, respectively, but the mode sizes were vague. Non-mixed mineral particles, sea salt, and mixed mineral-sea salt particles were the major particle types. Correspondingly, Al and Si were the most frequently detected elements. Frequencies of K-, Ca-, and S-containing particles were highest under foggy conditions, while the frequency of Na-containing particles was lowest. These results indicate that fog favored sulfate production on the particles and led to the deposited mineral particles more abundant in secondary salt, suggesting the importance to consider the dependence of the comoosition of deoosited mineral narticles on weather as well as narticle size.展开更多
A computational fluid dynamics model is used for the simulation of laminar flow ofwater-Al2O3 nanofluid in a confined slot impinging jet. The （steady-state and two-dimensional） Eulerian-Lagrangian model is used cons...A computational fluid dynamics model is used for the simulation of laminar flow ofwater-Al2O3 nanofluid in a confined slot impinging jet. The （steady-state and two-dimensional） Eulerian-Lagrangian model is used considering fluid-particle and particle-wall interactions （i.e., two-way coupling）. A collocated grid and the SIMPLE algorithm are used for the coupling of pressure and velocity fields. The deposition model is used to investigate the effect of particle deposition on the impingement surface. Results indicate that the particle trajectory becomes stable farther from the jet with a rising Reynolds number and jet- impingement surface distance ratio. The heat transfer coefficient of the mixture model is higher than that of the Eulerian-Lagrangican model.展开更多
基金Sponsored by the National Security Major Basic Research Project of China(Grant No.973 -61334)
文摘In this paper, an evolutionary recursive Bayesian estimation algorithm is presented, which incorporates the latest observation with a new proposal distribution, and the posterior state density is represented by a Gaussian mixture model that is recovered from the weighted particle set of the measurement update step by means of a weighted expectation-maximization algorithm. This step replaces the resampling stage needed by most particle filters and relieves the effect caused by sample impoverishment. A nonlinear tracking problem shows that this new approach outperforms other related particle filters.
基金supported by the National Natural Science Foundation of China(No.51735013).
文摘Based on aphid wax-honeydew marble and the hydrophobic wax structure of lotus and its derived applications with superareophilic and superhydrophobic properties,edible carnauba wax and beeswax particles were mixed and utilized to mimic lotus wax and wrap liquid,thus forming liquid marbles(LMs).Through the utilization of continuous production system(CPS),wax as an interfacial surfactant,water and solid,air-phase or mixed-phase marble content was produced.The edible liquid marble(ELM)could encapsulate water and food droplets.Edible solid marble(ESM)and edible solid hollow marbles(ESHMs)could be fabricated by applying pectin or syrup.Moreover,through the heating of wax powders with different melting temperatures,stable tablets and hollow capsules could be produced.The wax powder as interfacial surfactant could firmly bind with pectin through hydrogen bonds on ESM.The edible LMs can therefore be applied for residue reduction,corrosion reduction,biohazard prevention and cleaning in the food industry.The other phase LMs could act as novel tools in the pharmaceutical and food industries with the above-mentioned water transport,preservation,sustained releasing and selective releasing abilities.
基金financially supported by the National Natural Science Foundation of China(Grant No.51322601)the National Natural Science Foundation of China-China National Petroleum Corporation Joint Fund of Petrochemical Engineering(U1162122)the Fundamental Research Funds for the Central Universities (Grant No.HIT.BRETIV.201315)
文摘In this work, a discrete particle model （DPM） was applied to investigate the dynamic characteristics in a gas-solid bubbling fluidized bed of binary solid particles. The solid phase was simulated by the hard- sphere discrete particle model. The large eddy simulation （LES） method was used to simulate the gas phase. To improve the accuracy of the simulation, an improved sub-grid scale （SGS） model in the LES method was also applied. The mutative Smagorinsky constant case was compared with the previously published experimental data. The simulation by the mutative Smagorinsky constant model exhibited better agreement with the experimental data than that by the common invariant Smagorinsky constant model. Various restitution coefficients and different compositions of binary solids were investigated to determine their influences on the rotation characteristics and granular temperatures of the particles. The particle translational and rotational characteristic distributions were related to certain simulation parameters.
基金Financial support for the reported research by the National Natural Science Foundation of China(51076029)the Ministry of Science and Technology of China(China-EU International Collaboration Project 2010DFA61960)+1 种基金the Scientific Research Foundationof Graduate School of Southeast University(YBPY1401,YBJJ1119)China Academic Award for Doctoral Candidates is gratefully acknowledged
文摘This study presents a three-dimensional numerical study of the mixing and segregation of binary particle mixtures in a two-jet spout fluidized bed based on an Eulerian-Eulerian three-fluid model. Initially, the particle mixtures were premixed and packed in a rectangular fluidized bed. As the calculation began, the gas stream was injected into the bed from the distributor and jet nozzles. The model was validated by comparing the simulated jet penetration depths with corresponding experimental data. The main features of the complex gas-solid flow behaviors and the mechanism of mixing and segregation of the binary mixtures were analyzed, Moreover, further simulations were carried out to evaluate the effects of operating conditions on the mixing and segregation of binary particle mixtures. The results illustrate that mixing can be enhanced by increasing the jet velocity or enlarging the difference of initial proportions of binary particle mixtures.
基金This work was financially supported by the National Natu-ral Science Foundation of China(51806035)the Natural Science Foundation of Jiangsu Province(BK20170669)+1 种基金the Fundamental Research Funds for the Central Universities(2242018K40117)the Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development(Y707s41001).
文摘Coal-direct chemical-looping combustion(CDCLC)is a promising coal combustion technique that provides CO2 capture with a low energy penalty.In this study,we developed a three-dimensional Eulerian-Eulerian multiphase full-loop model for simulating the circulation and separation of binary particle mixtures in a novel high-flux CDCLC system.This model comprised a high-flux circulating fluidized bed as the fuel reactor(FR),a counter-flow moving bed as the air reactor(AR),a high-flux carbon stripper,two downcomers,and two J-valves.This model predicted the main features of complex gas-solid flow behaviors in the system.The simulation results showed that quasi-stable solid circulation in the whole system could be achieved,and the FR,AR,and J-valves operated in a dense suspension upflow regime,a near-plug-flow regime,and a bubbling fluidization regime,respectively.The multiphase flow model of binary particle mixtures was used to predict the mechanisms of directional separation of binary particle mixtures of an oxygen carrier(OC)and coal throughout the system.A decrease in the baffle aspect ratio of the inertial separator improved the coal selective separation efficiency but resulted in a slight decline in the OC selective separation;this is believed to be the result of weakening of particle collisions with the baffle.A higher FR gas velocity had a slightly negative effect on the OC selective separation efficiency,but improved the coal selective separation efficiency;this can be attributed to an increase in the particle-carrying capacity of the gas stream.A decrease in the coal particle size led to better entrainment of the coal particles by the gas stream and this increased the coal selective separation efficiency.In real CDCLC applications,the operating variables for separation of binary particle mixtures should be comprehensively assessed to determine their positive and negative effects on the carbon capture efficiency,OC regeneration efficiency,gas leakage restraint,energy consumption,and fuel conversion.
文摘The packing densification of binary spherical mixtures under 3D mechanical vibration was studied experimentally. The influences of vibration frequency （ω）, volume fraction of large spheres （XL）, sphere size ratio （r, diameter ratio of small to large spheres）, and container size （D） on the random binary packing density （p） were systematically analyzed. For any given set of conditions, there exist optimal ω and XL to realize the densest random binary packing; too large or small ω and XL is not helpful for densification. The influences of both r and D on p are monotonic; either reducing r or increasing D leads to a high value of p. With all other parameters held constant, the densest random packing occurs when XL is dominant, which is in good agreement with the Furnas relation. Moreover, the highest random binary packing density obtained in our work agrees well with corresponding numerical and analytical results in the literature.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 11272010, 11572004 and 11602088）. Tile China Postdoctoral Science Foundation （Grant No. 2016M592484） is also acknowledged.
文摘Particle elongation is an important factor affecting the packing properties of rod-like particles. However, rod-like particles can be easily bent into non-convex shapes, in which the effect of bending should also be of concerned, To explore the shape effects of elongation and bending, together with the size and volume fraction effects on the disordered packing density of mixtures of non-convex particles, binary and polydisperse mixtures of curved spherocylinders are simulated employing sphere assembly models and the relaxation algorithm in the present work. For binary packings with the same volume, curves of the packing density versus volume fraction have good linearity, while densities are plotted as a series of equidistant curves under the condition of the same shape. The independence of size and shape effects on the packing density is verified for mixtures of curved spherocylinders. The explicit formula used to predict the density of binary mixtures, by superposing the two independent functions of the size and shape parameters, is extended to include a non-convex shape factor. A polydisperse packing with the shape factor following a uniform distribution under the condition of the same volume is equivalent to a binary mixture with certain components. The packing density is thus predicted as the mean of maximum and minimum densities employing a weighing method.
基金This study was supported by the Education Bureau of Hebei Province for Excellent Young Scholars （YQ2014020）, the Natu- ral Science Foundation of Hebei Province （D2016402120） and the National Natural Science Foundation of China （41541038）. The Chinese Scholarship Council （CSC） supported Wei Hu＇s research at the Prefectural University of Kumamoto, Japan. We thank Ms. Jin-hui Shi and Ms. Cheng-cheng Chen for their assistance with particle collection, and Nicholas James O＇Connor for his assistance with editing.
文摘Dry deposited particles, larger than 1.3 μm, were collected under clear, cloudy, and foggy conditions during a cruise, traversing the Yellow Sea and the East China Sea from 23 March to 8 April 2011. In these areas, air masses are influenced by pollution outflows from the Asian continent. The size and elemental composition of dry deposited particles were investigated using a scanning electron microscope. Number-size distributions of these particles were approximately lognormal. Under clear conditions, the mode size was about 5.0 μm, with a mean diameter of 6.9 μm. Under cloudy and foggy conditions, the mean diameters were 5.7 and 6.0 μm, respectively, but the mode sizes were vague. Non-mixed mineral particles, sea salt, and mixed mineral-sea salt particles were the major particle types. Correspondingly, Al and Si were the most frequently detected elements. Frequencies of K-, Ca-, and S-containing particles were highest under foggy conditions, while the frequency of Na-containing particles was lowest. These results indicate that fog favored sulfate production on the particles and led to the deposited mineral particles more abundant in secondary salt, suggesting the importance to consider the dependence of the comoosition of deoosited mineral narticles on weather as well as narticle size.
文摘A computational fluid dynamics model is used for the simulation of laminar flow ofwater-Al2O3 nanofluid in a confined slot impinging jet. The （steady-state and two-dimensional） Eulerian-Lagrangian model is used considering fluid-particle and particle-wall interactions （i.e., two-way coupling）. A collocated grid and the SIMPLE algorithm are used for the coupling of pressure and velocity fields. The deposition model is used to investigate the effect of particle deposition on the impingement surface. Results indicate that the particle trajectory becomes stable farther from the jet with a rising Reynolds number and jet- impingement surface distance ratio. The heat transfer coefficient of the mixture model is higher than that of the Eulerian-Lagrangican model.
