scholarly journals CFD Investigations of Bath Dynamics in a Pilot-Scale TSL Furnace

2021 ◽  
Author(s):  
D. Obiso ◽  
M. Reuter ◽  
A. Richter
Keyword(s):  
Fluid Dynamics ◽  
Bubble Dynamics ◽  
Cfd Simulation ◽  
Bubble Formation ◽  
Numerical Approach ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Slag Bath ◽  
Front Tracking Method ◽  
Vof Model

AbstractThe hydrodynamics of a Top Submerged Lance (TSL) slag bath are investigated here by means of Computational Fluid Dynamics (CFD) simulation. The object of the study is the pilot-scale furnace located at TU Bergakademie Freiberg, where air is injected beneath the slag bath with a top lance. The fluid dynamics system is evaluated at operating conditions, with experimentally measured slag physical properties and real flow rates. The numerical approach is based on the Volume Of Fluid (VOF) model, a front-tracking method that allows the interface to be geometrically reconstructed. Using a fine computational grid, the multiphase interactions are calculated with a high level of detail, revealing the mechanisms of bubble formation and bath dynamics. Two lance configurations are compared, with and without a swirler, and the effect on the hydrodynamics is discussed with regards to key features of the process, such as bubble dynamics, slag splashing, the interface area, rotational sloshing, and bath mixing. The model predicts bubble frequencies in the range of 2.5 to 3 Hz and captures rotational sloshing waves with half the frequencies of the bubble detachment. These results agree with real furnace data from the literature, proving the reliability of the computing model and adding value to the empirical understanding of the process, thanks to the direct observation of the resolved multiphase flow features. The comparative study indicates that the air swirler has an overall positive effect in addition to the proposed enhancement of lance cooling, with an increase in the bath mixing and a reduction in the splashing.

scholarly journals Multi-Scale CFD Modeling of Plate Heat Exchangers Including Offset-Strip Fins and Dimple-Type Turbulators for Automotive Applications

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2965 ◽  
Author(s):  
Augusto Della Torre ◽  
Gianluca Montenegro ◽  
Angelo Onorati ◽  
Sumit Khadilkar ◽  
Roberto Icarelli
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Heat Exchangers ◽  
Internal Combustion Engines ◽  
Cfd Simulation ◽  
Full Scale ◽  
Operating Conditions ◽  
Plate Heat ◽  
Multi Scale ◽  
Macro Scale

Plate heat exchangers including offset-strip fins or dimple-type turbulators have a wide application in the automotive field as oil coolers for internal combustion engines and transmissions. Their optimization is a complex task since it requires targeting different objectives: High compactness, low pressure drop and high heat-transfer efficiency. In this context, the availability of accurate Computational Fluid Dynamics (CFD) simulation models plays an important role during the design phase. In this work, the development of a computational framework for the CFD simulation of compact oil-to-liquid heat exchangers, including offset-strip fins and dimples, is presented. The paper addresses the modeling problem at different scales, ranging from the characteristic size of the turbulator geometry (typically µm–mm) to the full scale of the overall device (typically cm–dm). The simulation framework is based on multi-scale concept, which applies: (a) Detailed simulations for the characterization of the micro-scale properties of the turbulator, (b) an upscaling approach to derive suitable macro-scale models for the turbulators and (c) full-scale simulations of the entire cooler, including the porous models derived for the smaller scales. The model is validated comparing with experimental data under different operating conditions. Then, it is adopted to investigate the details of the fluid dynamics and heat-transfer process, providing guidelines for the optimization of the device.

Numerical Investigation of Single Bubble Dynamics Passing a Mesh-Based Structure

2020 ◽  
Author(s):  
Fadi Alnaimat ◽  
Bobby Mathew ◽  
Omar Alhammadi
Keyword(s):  
Bubble Dynamics ◽  
Cfd Simulation ◽  
Single Bubble ◽  
Separation Mechanism ◽  
Mesh Structure ◽  
Flow Restriction ◽  
Complex Interactions ◽  
Vof Model ◽  
Single Bubble Dynamics ◽  
Physical Features

Abstract In this article, investigations of the dynamic behaviors of a single bubble flowing across a mesh-based structure domain was conducted using the volume of fluid (VOF) model. The study was investigated in various mesh structure sizes, including hole size and gap distance. The fundamental behavior of bubble deformation and the effects of gap sizes were analyzed. Subsequently, the predicted dynamics of the deforming bubble area and the effect of the surface tension were examined inside the mesh holes. The discharging bubbles from the mesh structure resulted in a slight difference in the physical features from the original bubble dynamics before entering the mesh (flow restriction). This drafted the bubbles in different trajectories and led to behave differently based on the mesh characteristics. The complex interactions and the subsequent deformations were observed between different mesh sizes. For the validation of the bubble dynamics, the results of computational fluid dynamics (CFD) simulation were tested under different mesh sizes detailing the velocity field, exiting trajectory, bubbles deformation, and residence time, which helps to reveal the affected parameters on the separation mechanism of the original bubble.

scholarly journals Performance Optimization of Ejector using Computation Fluid Dynamics

2020 ◽  
Vol 8 (5) ◽  
pp. 2905-2910
Keyword(s):  
Fluid Dynamics ◽  
Performance Optimization ◽  
Cfd Simulation ◽  
Experimental Testing ◽  
High Reliability ◽  
Fluid Velocity ◽  
Pressure Ratio ◽  
Operating Cost ◽  
Flow Characteristics ◽  
Operating Conditions

Ejector is a device used for carry low pressure fluids with no mechanical force, high pressure flow. This contains the main nozzle, chamber for suction, chamber for mixing and diffu ser.It is used in vaccum pumps, condensers, steam refrigeration, Because of its simple structure, gas mixing, pneumatic transport (no moving parts) and reliable operation. It is also used in pumps for lifting slurries and waste material containing solids from tanks and sumps. Due to their simplicity and high reliability, however, jet ejectors are widely used in industries with low efficie ncy. The project's goal is to optimize the efficiency of jet ejectors for each operating condition.Consequently, the primary fluid consumption and operating cost is minimized. A commercial computational fluid dynamics tool would be used to analyse the flow characteristics inside the ejector geometry. The results of the CFD simulation could be used to understand the effect of fluid velocity and pressure ratio on the ejector performance. The analysis would also be carried out by varying the primary and secondary nozzle dimensions. Performance of ejectors under various operating conditions is generally obtained through an experimental testing of prototype or scaled ejectors. The availability of performance parameters for such ejectors is limited, and experimental testing can be cost prohibitive.

scholarly journals A Simulation Study on Temperature Uniformity of Photovoltaic Thermal Using Computational Fluid Dynamics

2021 ◽  
Vol 82 (1) ◽  
pp. 21-38
Author(s):  
Mohd Afzanizam Mohd Rosli ◽  
Irfan Alias Farhan Latif ◽  
Muhammad Zaid Nawam ◽  
Mohd Noor Asril Saadun ◽  
Hasila Jarimi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Operating Conditions ◽  
Working Fluid ◽  
Percentage Error ◽  
Pv Module

The temperature distribution across the photovoltaic (PV) module in most cases is not uniform, leading to regions of hotspots. The cells in these regions perform less efficiently, leading to an overall lower PV module efficiency. They can also be permanently damaged due to high thermal stresses. To enable the high-efficiency operation and a longer lifetime of the PV module, the temperatures must not fluctuate wildly across the PV module. In this study, a custom absorber is designed based on literature to provide a more even temperature distribution across the PV module. This design is two standard sets of spiral absorbers connected. This design is relatively less complicated for this reason and it allows room for adjusting the pipe spacing without much complication. The absorber design is tested via computational fluid dynamics (CFD) simulation using ANSYS Fluent 19.2, and the simulation model is validated by an experimental study with the highest percentage error of 9.44%. The custom and the serpentine absorber utilized in the experiment are simulated under the same operating conditions having water as the working fluid. The custom absorber design is found to have a more uniform temperature distribution on more areas of the PV module as compared to the absorber design utilized in the experiment, which leads to a lower average surface temperature of the PV module. This results in an increase in thermal and electrical efficiency of the PV module by 3.21% and 0.65%, respectively.

Analysis of a Double Inlet Gerotor Pump: A Dynamic Multi-Phase CFD Approach Accounting for the Fluid Compressibility and Temperature Dependent Properties

2019 ◽  
Author(s):  
Massimo Milani ◽  
Luca Montorsi ◽  
Stefano Terzi ◽  
Gabriele Storchi ◽  
Andrea Lucchi
Keyword(s):  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Bubble Formation ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Fluid Temperature ◽  
Gerotor Pump ◽  
Fluid Properties ◽  
Intake Pressure ◽  
Multi Phase

Abstract The paper analyzes the fluid dynamic performance of a double inlet Gerotor pump by means of a multi-phase and multicomponent CFD approach. The numerical simulation includes the full 3D geometry of the pump as well as the real physics of the compressible hydraulic fluid and the rotating dynamic motion. The aeration and cavitation phenomena are included in the analysis adopting the Rayleight-Plesset equation and inertia controlled growth model for bubble formation. Cavitation and aeration phenomena are detected, especially when intake pressure is lower than atmospheric pressure. The influence of the fluid temperature variation on the component performance is also numerically predicted. The accuracy of a detailed modelling of the fluid properties variation with respect to the temperature and pressure is addressed and the effects on the numerical results is investigated. The rotational speeds of the internal and the external gears of the pump and the engagement between the teeth are addressed by means of an overset mesh approach. Constant leak height is considered between the gears and the case, while the overset mesh approach is adopted in order to accurately predict the leakage due to the teeth engagement. This numerical approach enables to investigate the dynamic performance of Gerotor gear pumps in terms of flow rate and pressure ripples and volumetric efficiency under standard and critical (actual) operating conditions. Good agreement between numerical and experimental results was found for specific operating conditions.

Fluid dynamics of a pilot scale OrbShake bioreactor under different operating conditions

2021 ◽  
Author(s):  
Likuan Zhu ◽  
Chunyang Zhao ◽  
Angus Shiue ◽  
Jyh‐Cheng Jeng ◽  
Maria J. Wurm ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Pilot Scale ◽  
Operating Conditions

scholarly journals Simulation on flow field and gas hold-up of a pilot-scale oxidation ditch by using liquid-gas CFD model

2018 ◽  
Vol 78 (9) ◽  
pp. 1956-1965 ◽  
Author(s):  
Qi Xu ◽  
Jiakuan Yang ◽  
Huijie Hou ◽  
Yuchen Hu ◽  
Sha Liang ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Velocity ◽  
Test Site ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Oxidation Ditch ◽  
Cfd Model ◽  
Two Phase ◽  
Vof Model ◽  
Optimal Setting

Abstract A liquid–gas two-phase computational fluid dynamics (CFD) model was developed to simulate flow field and gas hold-up in a pilot-scale oxidation ditch (OD). The volume of fluid (VOF) model and the mass flow inlet boundary condition for gas injection were introduced in this model. The simulated values of the flow velocities and the gas hold-up were verified by experimental measurements in the pilot-scale OD. The results showed that the gas hold-up at test-site 3, immediately downstream of the surface aerator, was the highest among all three test-sites. Most of the gas existed in the upper portion of the ditch and was close to the inner side of the channel. Based on the liquid–gas two-phase CFD model, three operating conditions with different setting height ratios of the submerged impellers were simulated. The simulated results suggested that the setting heights of the submerged impellers have significant impacts on the flow velocity distribution. Lowering the setting height could increase the flow velocity in the pilot-scale OD. An optimal setting height ratio of 0.273 was proposed, which would be beneficial for minimizing sludge sedimentation, especially near the inner side of the curve bend.

Prediction of Deposition Patterns in a Pilot-Scale Spray Dryer Using Computational Fluid Dynamics (CFD) Simulations

2007 ◽  
Vol 2 (3) ◽  
Author(s):  
Kashinath Kota ◽  
Tim Langrish
Keyword(s):  
Fluid Dynamics ◽  
Flow Rate ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Spray Dryer ◽  
Air Flow Rate ◽  
Cfd Simulations ◽  
Deposition Fluxes ◽  
Deposition Patterns ◽  
Computational Fluid Dynamics Cfd

This paper presents the predictions of deposition patterns using CFD simulations based on transient-flow behaviour of a 1.6 m high, 0.8 m diameter, pilot-scale spray dryer, following from previous studies assessing the use of Computational Fluid Dynamics (CFD) simulations to predict the deposition on a plate in a simple box configuration. The predicted deposition fluxes here have been compared with experimental data for the deposition fluxes of skim milk, maltodextrin and water. The CFD simulation results suggested that the effect of transient air flows on the vertical patterns of deposition fluxes with distance up the dryer wall for no inlet air swirl is small. The CFD simulations underpredicted the experimental values of the deposition fluxes by approximately 50%, but the simulations predicted the same experimental trends when changing the main air flow rate through the dryer. The experimentally-measured deposition fluxes were 38%, on average, higher at a main air flow rate of 113 kg/h compared with those at a flow rate of 88 kg/h. The CFD simulations predicted an average increase in deposition flux of 26% at 113 kg/h compared with 88 kg/h, so the trends with this change in operating conditions have been predicted well by the CFD simulations. One-way particle coupling has therefore shown correct trends in the deposition fluxes with respect to both positions in the dryer and different operating conditions, and such one-way coupling is several orders of magnitude faster than the more rigorous two-way coupling.

CFD Simulation of the Fluidized Bed Applied in the Synthesis of Benzene Series Organosilicon

2013 ◽  
Vol 753-755 ◽  
pp. 2663-2666
Author(s):  
Xin Feng Han ◽  
Jian Long Li ◽  
Ning Xu
Keyword(s):  
Mathematical Model ◽  
Fluidized Bed ◽  
Granular Flow ◽  
Cfd Simulation ◽  
Bubble Formation ◽  
Simple Algorithm ◽  
Operating Conditions ◽  
Multiphase Models ◽  
The Mathematical Model ◽  
Benzene Series

The mathematical model of gas-solid flow 2D fluidized bed was established. The CFD simulation was carried out with commercial software FLUENT6.3 by using Eulerian-Eulerian multiphase models, based on the kinetic theory of granular flow and PC-SIMPLE algorithm. In order to provide a basis on optimizing the operating conditions of the fluidized bed applied in benzene series organosilicon reactor, the processes of bubble formation, growth and disappearance under different cases were analyzed.

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