Experimental study of flow regimes and dust emission in a free falling particle stream

Wang, Yi; Ren, Xinrong; Zhao, JiangPing; Chu, Zongkun; Cao, Yingxue; Yang, Yang; Duan, Mengjie; Fan, Hang; Qu, Xinrui

doi:10.1016/j.powtec.2016.01.016

Cited by 21 publications

(7 citation statements)

References 23 publications

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“…The first map showed fines carried away by circulating air currents to form a re-circulating region close the centrally fed particle jet. This finding is consistent with (Wypych et al 2005) and (Wang et al 2016) who identified a high recirculating region near a falling particle stream which accelerates the migrations of fines into the surrounding air. The upward moving air near the silo wall gradually reduces its velocity with entrained particles gradually settling to the bottom (Rani et al 2015).…”

Section: Dust Concentration Measurements Using Optical Methodssupporting

confidence: 91%

“…Researcher e.g. (Réthoré et al 2014), (Wang et al 2016) and (Krueger et al 2015) suggest the use of optical methods such as using a single camera for measuring the settling of particles in a silo during the filling process and evaluating the particle displacements by correlating digital images. The displacement of fines following air currents in the silo can be estimated from the images as successive positions over time.…”

Section: Introductionmentioning

confidence: 99%

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Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations

Waduge

Zigan

Stone

et al. 2017

Process Safety and Environmental Protection

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-Trinanes, P. (2017). Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations. Process Safety and Environmental Protection, Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations AbstractOne of the main challenges in industries handling biomass is the consequence of the particle breakage of pelletised biomass in smaller fractions which can lead to fine particles smaller 500 ¿m that can form dust clouds in the handling and storing equipment. These dust clouds present potential health and safety hazards as well as dust explosion hazards to plant operators because the airborne dust can occur in high concentrations close to the dust explosion limits of the biomass material, during the filling process of storage silos. Preventing dust explosions and the damage of plant infrastructures requires a profound understanding of the particle/air dynamics in the dust cloud circulating in the storage silo. The limited access to the storage facilities as well as the silo size requires a detailed study of the particle/air dynamics at different scales. Lab scale experiments were conducted as a first step to establishing a new optical method for measuring particle concentrations. A small scale experimental rig was fed centrally with different sized wood pellets and a single camera and a laser was utilised to capture the dust concentration in different areas of the silo. According to the experimental results, a higher mass concentration of dust was observed near the silo wall as well as near the main particle jet. However, the mass concentrations were below the explosive limits at the area in between main particle jet and silo wall. These experimental results were then feeding into a 2D CFD simulation representing the particle dynamics in the laser sheet (2D plane). Qualitative findings show a good agreement of the particle/air dynamics between experiments and simulations. AbstractBiomass generates a increasing interest as renewable fuel and industries handling biomass show fast levels of growths over the last decade and, yet, several challenges remain in the handling, transporting and storing of biomass such as wood pellets. One challenge is the consequence of the particle breakage of pelletised biomass in smaller fractions which can lead to fine particles smaller 500 microns which can form dust clouds in the handling and storing equipment. These dust clouds present potential health and safety hazards as well as dust explosion hazards to plant operators because during the filling process of storage silos the airborne dust can occur in high concentrations close to the dust explosion limits of the 2 biomass material. Preventing dust explosions and the damage of plant infrastructures requires a profound understanding of the particle/ air dynamics in the dust cloud circulating in the storage silo. The limited access to the storage facilities as well as the silo size require a detailed study of the particle/ air dynamics a...

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Section: Dust Concentration Measurements Using Optical Methodssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations

Waduge

Zigan

Stone

et al. 2017

Process Safety and Environmental Protection

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“…In the literature, many experimental studies on the discharge of a silo were conducted. Some of these were dedicated to the characterization of the granular flow inside the silo [3][4][5] and others on the quantification and understanding of the mechanisms responsible of the granular jet spreading [6][7][8][9][10][11]. These studies showed that the flow rate of induced air into the stream is one of the key to the granular jet expansion.…”

Section: Introductionmentioning

confidence: 99%

Eulerian modelling of the powder discharge of a silo: Attempting to shed some light on the origin of jet expansion

Audard

Fede

Belut³

et al. 2021

Powder Technology

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Powder discharging from a silo provokes an emission of dust. To understand and prevent this source of danger, 3D simulations of a silo discharge were performed using an Euler-Euler approach. The impact of the coupling between the flow inside the silo and the granular jet in free-fall is analyzed. Results show that the solid mass flow rate is correctly predicted and that gas back-flowing at the hopper exhaust appears responsible for the formation of a fluctuating and radially expanding jet. However, the radial expansion of the free-falling jet is underestimated. Stochastic fluctuations of the particles velocity at the hopper exhaust are introduced to evaluate their effect on the downstream development of the free-falling jet. These fluctuations are found capable of generating a development of the jet similar to that observed experimentally. This suggests that the granular flow conditions at the hopper exhaust are responsible for the further dispersion of powder.

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“…The processes of loading bulk materials are accompanied by significant dust release, which negatively affects the environment, human health [1,2], equipment service life and can lead to explosions and fires [3]. The reasons for the generation and spread of dust are both the process of air ejection by bulk material [4,5] and secondary dust generation during the interaction of the flow with the surface [6,7]. One of the ways to reduce dust generation is to reduce the flow rate of the ejected air [8,9].…”

Section: Introductionmentioning

confidence: 99%

Reduced Dust Generation when Loading a Bunker with Powdery Material. Part 1. Research Methods

et al. 2021

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Experimental study of flow regimes and dust emission in a free falling particle stream

Cited by 21 publications

References 23 publications

Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations

Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations

Eulerian modelling of the powder discharge of a silo: Attempting to shed some light on the origin of jet expansion

Reduced Dust Generation when Loading a Bunker with Powdery Material. Part 1. Research Methods

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