Computational Fluid Dynamics (CFD) Modeling of Swirling Flows in Industrial Counter-Current Spray-Drying Towers under Fouling Conditions

Hernández, Borja; Fraser, Blair A.; Juan, Luis Martín de; Martı́n, Mariano

doi:10.1021/acs.iecr.8b02202

Cited by 22 publications

(21 citation statements)

References 43 publications

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“…A higher amount of deposits involves more irregularities on the wall surface at a large scale, which results in a higher roughness and consequently in an increase in the WSS . Our previous work demonstrated a reasonable accuracy to predict the decay under varying deposition levels …”

Section: Rtd: Experimental Characterizationmentioning

confidence: 92%

“…In particular, wall boundary conditions play a major role in reproducing the vortex since the friction generated by rough walls reduces the angular momentum. Our previous work demonstrated the use of logarithmic laws with an additive constant to reproduce the effect of roughness under different levels of deposition and Re .…”

Section: Rtd: Modeling Frameworkmentioning

confidence: 99%

“…A rigorous computational fluid dynamics (CFD) modeling platform to describe spray dryers should undergo a sequential validation. − One must ensure that a proper reproduction of an isothermal single-phase flow is available before incorporating the momentum transfer in multiphase isothermal systems . Then, one can describe heat and mass transfer including an equation of state, the energy equation, and single droplet drying models.…”

Section: Introductionmentioning

confidence: 99%

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The Use of Optimized Restitution Coefficients to Improve Residence Time Prediction in Computational Fluid Dynamics-Discrete Parcel Method Models for Counter-Current Spray Dryers

Hernández

Francia

Crosby

et al. 2021

Ind. Eng. Chem. Res.

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This work studies the dispersion of solids in the cold isothermal operation of swirl counter current spray dryers. Residence time distributions (RTDs) of glass beads and detergent powder are obtained in a semi-industrial unit under varying Reynolds and injection positions and validated with the results of a novel Reynolds average Navier Stokes-discrete parcel method (DPM) framework. The simulations stress that the particle RTD is governed to a large extent by the interaction of the solids with the walls, which is usually simplified with the assumption of a particle-wall restitution coefficient. Since this is often unavailable experimentally, here, we propose an alternative combined model that integrates the computational fluid dynamics (CFD)-DPM model with reinforcement learning using a training set of experimental RTDs to extract an "effective pair of wall restitution coefficients". The method improves the accuracy of existing CFD platforms, reducing the errors in the mean residence time from 30−100% to <25%.

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Section: Rtd: Experimental Characterizationmentioning

confidence: 92%

Section: Rtd: Modeling Frameworkmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Use of Optimized Restitution Coefficients to Improve Residence Time Prediction in Computational Fluid Dynamics-Discrete Parcel Method Models for Counter-Current Spray Dryers

Hernández

Francia

Crosby

et al. 2021

Ind. Eng. Chem. Res.

Self Cite

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“…It shows that increasing inlet number could decrease pressure loss and increase vortex and swirl generation [19]. The other research shows that increasing vortex and swirl generation could increase mixing compounds and heat transfer rate [17,20,21,22].…”

Section: Introductionmentioning

confidence: 90%

Numerical analysis of the vortex flow effect on the thermal-hydraulic performance of spray dryer

Anggara

Romahadi

Avicenna

et al. 2022

Sinergi

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The use of a spray-dryer is very popular in the drying process in the food and beverage industry. However, due to the properties of the sensitive product that the quality will degrade in drying at high temperature, the innovative design of spray-dryer is developed which can increase the heat transfer rate at moderate temperature. This research was conducted to develop a spray-dryer design to improve thermal-hydraulic performance, with a high transfer rate and low-pressure drop at such a temperature. The design varies by several inlets categorized as design A with one inlet, design B with two inlets, and design C with three inlets. This simulation uses ANSYS FLUENT17, and the independence of the mesh was evaluated to improve the result of the simulation. The efficient mesh number is obtained from the independence of the mesh at around one million. The result shows that design C has the lowest pressure loss and the highest transfer rate due to high vortex and swirl flow generation, improving the mixture quality and direct contact between droplet and dry-air.

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“…Internal swirling flows with high intensity and the presence of vortex breakdown may be characterized by their anisotropy for the Reynolds stresses. This anisotropy can be described following the equation (2.10), where the first term refers to the Reynolds stress contribution and the second term is the dissipation of turbulence (HERNANDEZ et al, 2018).…”

Section: Turbulence and Swirling Flowmentioning

confidence: 99%

Simulação numérica de um escoamento turbulento não-reativo no interior de uma caldeira ciclônica industrial usando LES e URANS

Pereira¹

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A numerical simulation of a non-reactive turbulent flow inside a cyclonic industrial CO boiler was investigated in order to understand the swirling formation, the fluid behavior in different locations inside the domain and the distribution of chemical species. As 80% of the energy matrix in Brazil is generated by combustion processes and government regulations about NOx emissions are becoming more restrict, enhancing combustion efficiency in a CO boiler with a turbulent swirling flow to reduce pollutant emissions has become an engineering research topic. Enhancing mixing processes through turbulent swirling flows might reduce thermal NOx formation. Computational fluid dynamics simulations were realized using the in-house MFSim code with the turbulent closure models LES, URANS Standard k − ε, URANS Standard k − ε Modified and URANS Realizable k − ε. A theoretical basis about turbulence, LES and URANS closure models, mixing and swirling flows was provided. A state of art comprising different authors pointed out that some works with URANS Standard k − ε demonstrated a premature solid-body rotation formation due to its eddy viscosity assumption and that swirling flows may reduce pollutant emissions by improving mixing of reactants and decreasing flame temperature. Validations concerning multi-component mixing flows and Immersed Boundary method were presented. From the results, LES and URANS Standard k − ε presented similar velocity field results, capable of capturing the swirling formation. When analyzing three URANS closure models, a turbulent kinetic energy graph illustrated that it is relevant to observe the modeled part and the value obtained from velocity field fluctuations. The modified model presented low turbulent viscosity values and an LES-like behavior, with similar results to the standard model. The realizable model presented distant results comparing to the other models studied and there was no reverse flow in its swirling core. Adding different chemical species did not modify the velocity field and the highest mixing level was obtained in the most intense turbulent swirling region, close to the inlets. The data provided may assist in the comprehension of swirling formation, mixture processes inside a boiler and temperature control to reduce pollutant emissions.

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Computational Fluid Dynamics (CFD) Modeling of Swirling Flows in Industrial Counter-Current Spray-Drying Towers under Fouling Conditions

Cited by 22 publications

References 43 publications

The Use of Optimized Restitution Coefficients to Improve Residence Time Prediction in Computational Fluid Dynamics-Discrete Parcel Method Models for Counter-Current Spray Dryers

The Use of Optimized Restitution Coefficients to Improve Residence Time Prediction in Computational Fluid Dynamics-Discrete Parcel Method Models for Counter-Current Spray Dryers

Numerical analysis of the vortex flow effect on the thermal-hydraulic performance of spray dryer

Simulação numérica de um escoamento turbulento não-reativo no interior de uma caldeira ciclônica industrial usando LES e URANS

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