Mathematical Model Based on DSMC Method for Particulate Drying in a Coaxial Impinging Stream Dryer

Du, Ming; Gong, Jun; Chen, Wei; Wang, Qian

doi:10.1080/07373937.2014.969841

Cited by 16 publications

(6 citation statements)

References 16 publications

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“…Subsequently, Tamir carried out extensive fundamental and applied research on impinging streams [2]. Impinging stream reactors have been widely applied and investigated in numerous industrial applications, including the drying of high-moisture particles [3][4][5], fast preparation of nanoparticles [6,7], fluid micromixing [8,9], absorption [10,11] and liquid-liquid extraction [12]. Compared to common methods, impinging stream methods can enhance the momentum, heat, and mass transfer of the relevant reaction process because there is a larger relative velocity and pressure gradient in the impingement region formed by the collision of two opposite jets [1].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Studies on Flow and Turbulence Characteristics of Impinging Stream Reactors with Dynamic Inlet Velocity Variation

Liu

Yue²,

et al. 2018

Energies

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Impinging stream technique has been widely used in engineering industries. Insufficient data are available on the effects of dynamic inflow conditions on the flow and turbulence characteristics of an impinging stream reactor. In this study, we investigate and discuss the flow and turbulence characteristics of an impinging stream reactor with dynamic inlet velocity variation, e.g., sinusoidal, parabolic, step or triangular variation. The effects of period, amplitude, phase difference, mean inlet velocity and type of dynamic inlet velocity variation on the motional behaviors of the impinging surface and the mean turbulence kinetic energy (k) of the impingement region are investigated and discussed using particle image velocimetry (PIV) and computational fluid dynamics (CFD) at various values of L/D (the ratio of impinging spacing to nozzle diameter). The results show that the impinging surface makes back-and-forth motions in impinging stream reactors with dynamic inlet velocity variation. The mean k of the impingement region during one period is dominated by both the inlet velocity conditions and the geometric configuration. Dynamic inflow conditions bring more turbulence energy and pulsating characteristics to impinging zones over constant inlet velocity for an instantaneously moving impinging surface. Impinging stream reactors with dynamic inlet velocity variation provides more intense turbulence properties over conventional impinging stream reactors at the same mean inlet velocity. This work shows that the impinging streams with dynamic inlet velocity variation has strong potential for future relevant reactors and processes for engineering applications.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Studies on Flow and Turbulence Characteristics of Impinging Stream Reactors with Dynamic Inlet Velocity Variation

Liu

Yue²,

et al. 2018

Energies

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“…Du et al [10,11] presented a simulation of the particle motion behavior in the drying process in an ISD using the modified direct simulation Monte Carlo (DSMC) method. They found that the oscillatory motion of particles could increase the mean residence time of particles and intensify the drying process.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Modeling and Design of Parboiled Paddy-Impinging Stream Dryer Using the CFD-DEM Model

Swasdisevi,

Thianngoen,

Prachayawarakorn

2024

Foods

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Impinging stream dryers (ISDs) are effective for removing moisture from particulate materials because of the complex multiphase transport of air particles in ISDs. Nowadays, computational techniques are powerful to simulate multiphase flows, including dilute and dense-phase gas–solid flows and hence, the use of a reliable computational model to simulate the phenomena and design a dryer has recently received more attention. In this study, computational fluid dynamics, combined with the discrete element method (CFD-DEM) and falling drying rate model, were used to predict the multiphase transport phenomena of parboiled paddy in a coaxial ISD. The design of an impinging stream pattern for improving residence time in a drying chamber of ISD was also investigated. The results showed that the CFD-DEM, in combination with the falling drying model, could be well-utilized to predict the particle motion behavior and lead to more physically realistic results. The predicted change of moisture content in parboiled paddy was in good agreement with the experimental data for 17 cycles of drying. Although the prediction of mean residence time was lower than the experimental data, the predicted mean residence time was a similar trend to the experimental data. For ISD design, the simulation revealed that the use of two stages of impinging stream region (two streams collide at the top of the drying chamber at the first stage and then the gas particles flow on the incline floor to collide with the other stream at second stage) in a drying chamber could increase the residence time approximately 75% and reduce drying cycle from 17 to 10 cycles when it was considered at the same final moisture content.

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“…The impinging stream technique was first proposed by the Soviet scientist Elperin in 1961, and then investigated and discussed by many scholars and scientists [1][2][3][4]. The impinging stream reactor can effectively strengthen interphase heat and mass transfer, and thus is widely used in drying [5,6], absorption [7,8], micromixing [9][10][11], combustion [12], crystallization [13], extraction [14,15], nanoparticles preparation [16,17], and so on, which has created great potential for engineering applications.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulations of a Gas–Solid Two-Phase Impinging Stream Reactor with Dynamic Inlet Flow

Liu

Yue²,

et al. 2018

Energies

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Fluid flow characteristics and particle motion behavior of an impinging stream reactor with dynamic inlet flow (both inlet velocity patterns exhibit step variation) are investigated and discussed with the computational fluid dynamics–discrete element method (CFD–DEM). The effect of T (variation period of the dynamic inlet flow) and ∆u (inlet velocity difference) on the motion characteristics of single and multiple particles, as well as the mean particle residence time, are studied and discussed. The research results indicate that, compared with the traditional impinging stream reactor (both inlet velocities are equal and constant) with equal mean inlet velocity (um) within one period, the impinging surface is instantaneously moving and the flow regime is varied with time in the impinging stream reactor with dynamic inlet flow. The impinging stream reactor with dynamic inlet flow provides higher cost performance over the traditional impinging stream reactor, under equal um, in terms of single-particle residence time. Moreover, three new particle motion modes exist in multi-particle motions of the impinging stream reactor with dynamic inlet flow; particles are accelerated by the original or reverse fluid and perform oscillatory motion at least once after an interparticle collision. Whether it is a single particle or multi-particles, the mean particle residence time reaches a maximum value when T/2 is approximately equal to the first particle acceleration time, since the maximum axial kinetic energy increases in every oscillatory motion compared with traditional impinging stream, and the number of oscillatory motions is increasing. The mean residence time of a particle in the impinging stream reactor with a dynamic inlet flow increases with increasing ∆u, since the dynamic inlet conditions and increasing ∆u can continuously supply more energy to particles and thus cause more particles to enter one of the three new modes of particle motion.

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Mathematical Model Based on DSMC Method for Particulate Drying in a Coaxial Impinging Stream Dryer

Cited by 16 publications

References 16 publications

Experimental and Numerical Studies on Flow and Turbulence Characteristics of Impinging Stream Reactors with Dynamic Inlet Velocity Variation

Experimental and Numerical Studies on Flow and Turbulence Characteristics of Impinging Stream Reactors with Dynamic Inlet Velocity Variation

Mathematical Modeling and Design of Parboiled Paddy-Impinging Stream Dryer Using the CFD-DEM Model

Numerical Simulations of a Gas–Solid Two-Phase Impinging Stream Reactor with Dynamic Inlet Flow

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