Numerical simulation of ash particles deposition in rectangular heat exchange channel

Han, Zhiyu; Xu, Zhiming; Yu, Xiaoli; Sun, Aodi; Li, Yanfeng

doi:10.1016/j.ijheatmasstransfer.2019.01.114

Cited by 31 publications

(7 citation statements)

References 28 publications

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“…The problem will even be more complicated should the object be another fluid immiscible with the surrounding fluid. The governing equations that are applicable to all phases represent conservation laws of mass and momentum [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. As mentioned, these equations can apply to all fluid regions augmented with equations at the interface between phases.…”

Section: Governing Equationsmentioning

confidence: 99%

A Unified, One Fluid Model for the Drag of Fluid and Solid Dispersals by Permeate Flux towards a Membrane Surface

2021

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The drag of dispersals towards a membrane surface is a consequence of the filtration process. It also represents the first step towards the development of the problem of fouling. In order to combat membrane fouling, it is important to understand such drag mechanisms and provide a modeling framework. In this work, a new modeling and numerical approach is introduced that is based on a one-domain model in which both the dispersals and the surrounding fluid are dealt with as a fluid with heterogeneous property fields. Furthermore, because of the fact that the geometry of the object assumes axial symmetry and the configuration remains fixed, the location of the interface may be calculated using geometrical relationships. This alleviates the need to define an indicator function and solve a hyperbolic equation to update the configuration. Furthermore, this approach simplifies the calculations and significantly reduces the computational burden required otherwise if one incorporates a hyperbolic equation to track the interface. To simplify the calculations, we consider the motion of an extended cylindrical object. This allows a reduction in the dimensions of the problem to two, thereby reducing the computational burden without a loss of generality. Furthermore, for this particular case there exists an approximate analytical solution that accounts for the effects of the confining boundaries that usually exist in real systems. We use such a setup to provide the benchmarking of the different averaging techniques for the calculations of properties at the cell faces and center, particularly in the cells involving the interface.

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Section: Governing Equationsmentioning

confidence: 99%

A Unified, One Fluid Model for the Drag of Fluid and Solid Dispersals by Permeate Flux towards a Membrane Surface

2021

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“…Han et al [14] proposed a deposition model considering particle bounce to study the deposition of fly ash particles in gas in a 3D rectangular channel. The model was adopted in a CFD-DEM (Computational Fluid Dynamics-Discrete Element Method) sequential coupling method.…”

Section: Introductionmentioning

confidence: 99%

Zinc ash deposition pattern and structural optimization in the continuous hot-dip galvanizing vertical furnace

Dong

Dou

et al. 2023

J. Phys.: Conf. Ser.

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In a continuous hot-dip galvanizing vertical furnace for strip steel, zinc vapor oxidizes in the snout of the furnace to form zinc ash. The zinc ash adheres and agglomerates on the inner walls of the snout. If the zinc ash falls off and adheres to the surface of the strip, zinc ash defects will be formed, thereby affecting the surface quality of the galvanized layer. Given that the snout connects the annealing furnace and the zinc pot, the zinc ash will be transported into the annealing furnace and form nodulation on the roller, affecting the normal operation of the equipment. To study the deposition pattern of zinc ash inside the snout, a model of particle movement and deposition is established in this work to predict the movement and deposition characteristics of zinc ash particles, and it is verified by literature. On this basis, the zinc ash deposition patterns of three improvement cases of snout structure are compared. Results show that all three improvement schemes can effectively reduce the deposition rate of the zinc ash particles in the annealing furnace. In the case of slotted-baffle-added-only, although adding slotted baffles reduces the deposition of zinc ash in the furnace, it also increases the deposition rate in the snout and entry sections. In the case of exhaust-duct-added-only, the addition of the exhaust duct not only reduces the overall deposition rate in the furnace, but also effectively reduces the deposition rate in the snout and the entry section. By contrast, the scheme with slotted baffles and exhaust ducts is the most effective in inhibiting the diffusion of zinc ash.

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“…Li et al counted the particle deposition probability of different carbon conversion rates and simulated the particle deposition behavior during the transformation of carbon slag under gasification conditions. So far, the simulation and experimental devices mentioned have been able to demonstrate some aspects of the principle of particle deposition, − but due to the complex environment of the gasifier, the behavior of particle movement in the gasifier is difficult to determine.…”

Section: Introductionmentioning

confidence: 99%

Study of the Deposition Characteristics of Particles on the Slag Wall of a Gasifier

Bai

Song

Wei

et al. 2023

Ind. Eng. Chem. Res.

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In this work, the behavior of coal char particles adhering to the slag wall was studied. The effects of slag thickness and particle size on the restitution coefficient and probability of deposition were mainly discussed. In addition, the types of particle deposition were also classified. The results of exploring the effect of particle size on the coefficient of restitution show that the restitution coefficient of coal char particles hitting the slag wall surface has a complex dimensional effect, with a maximum and minimum coefficient of restitution occurring at the same particle size, a phenomenon referred to in this paper as the discrete effect. The minimum restitution coefficient greater than 0 is regarded as the critical restitution coefficient (ε f), and it is considered that particles with theoretical restitution coefficient higher than εf will bounce off the slag wall. With the particle diameter of 600 μm as the boundary, ε f first decreases and then increases. The maximum restitution coefficient increases with an increasing particle size of less than 600 μm and stays at a maximum value of 0.62 when the particle size is more than 600 μm. Moreover, the fragmentation of particles occurs at the particle size of 840–1600 μm. The discrete effect was also observed in the experimental data for the investigation of slag thickness, ε f increases with the increase of the slag thickness, and the maximum possible restitution coefficient does not change with the thickness of the slag. In addition, according to the statistics of the deposition probability, it is found that the smaller the particle size, the greater the deposition probability, the thicker the slag thickness, and the easier it is to deposit.

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Numerical simulation of ash particles deposition in rectangular heat exchange channel

Cited by 31 publications

References 28 publications

A Unified, One Fluid Model for the Drag of Fluid and Solid Dispersals by Permeate Flux towards a Membrane Surface

A Unified, One Fluid Model for the Drag of Fluid and Solid Dispersals by Permeate Flux towards a Membrane Surface

Zinc ash deposition pattern and structural optimization in the continuous hot-dip galvanizing vertical furnace

Study of the Deposition Characteristics of Particles on the Slag Wall of a Gasifier

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