CFD Simulation of the Sidewall Fired Tubular Reforming Furnace

2002 ◽  
Author(s):  
Per Nielsen ◽  
Lars J. Christiansen
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Temperature Field ◽  
Thermal Radiation ◽  
Computational Model ◽  
Temperature Profile ◽  
Flue Gas ◽  
Process Model ◽  
High Efficiency ◽  
Cfd Simulation

This paper describes simulations of Haldor Topsoe designed reforming furnaces. These furnaces are fired by a matrix of burners on the two sidewalls. The burners provide the heat needed for the reactions taking place inside vertical catalyst-filled tubes. The main objective is to get a better understanding of the flow and temperature field on the flue gas side, thus making it possible to enhance the design of high efficiency reformers. The simulations on the furnace side include models for combustion and thermal radiation. A separate CFD simulation is performed on the process side. An appropriate method has been introduced for the coupling of the furnace model with the process model thus eliminating the need for using an assumed temperature profile as boundary condition on the outer tube walls. The computational model has been verified by performing simulations on a pilot reformer. The numerical results agree well with the experimental data.

Evaluation of Boundary Conditions for CFD Simulation of Liquid Food Thermal Process in Glass Bottles

2012 ◽  
Vol 7 (6) ◽  
Author(s):  
Pedro Esteves Duarte Augusto ◽  
Marcelo Cristianini
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Temperature Profile ◽  
Thermal Process ◽  
Cfd Simulation ◽  
Convective Heat Transfer Coefficient ◽  
Food Products ◽  
Food Preservation ◽  
Heating Water ◽  
Experimental Values

The growing demand for safer and high-quality food products creates the need for better knowledge of the processes involved in food production. The computational fluid dynamics (CFD) have been widely used to better understand food thermal process, one of the safest and most frequently used methods for food preservation. However, no consistency in mathematical models has been observed, especially on the boundary conditions definition. The present study has evaluated four methodologies for the definition of boundary conditions for heating water in two commercial bottles: (M1) temperature profile of heating water (T∞) and convective heat transfer coefficient (h), (M2) T∞ as boundary condition for the outside package wall, (M3) T∞ as boundary condition for the outside heated liquid edge, and (M4) internal temperature profile (T=T(x,y,z,t)), previously measured in the inner package wall, as boundary condition for the outside heated liquid edge. Models that considered the measured value of h e T∞ as boundary condition showed good agreement with experimental values, compared by thermal history and sterilization value (F). The models that considered the temperature profile of the heating water or the inner package wall as boundary conditions, showed faster heating. By over-estimating the product heating rate, those models are not appropriated for thermal process modelling, as it compromises the safety and preservation of food products.

Theoretical Study of Temperature Distribution though Pasteurization for Orange Juice Based on 3D CFD Simulation

2013 ◽  
Vol 740 ◽  
pp. 242-248
Author(s):  
Jing Xie ◽  
Yong Yan Lin ◽  
Jin Feng Wang ◽  
Yi Tang ◽  
Miao Chen
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Temperature Field ◽  
Orange Juice ◽  
Cfd Simulation ◽  
Theoretical Study ◽  
Different Temperatures ◽  
The Cost

Computational fluid dynamics is a blanch of hydromechanics which is used to analyze the properties and heat transfer for different flows. With the developments of the computer science and CFD software itself, CFD has been applied into every field in engineering which can save the cost and time of research. This article simulated three different temperatures (85°C, 88°C, 90°C) of pasteurization to orange juice and got the temperature field in each pasteurization temperature After compared with the experimental data, the simulation model was improved and optimal computational way was got finally.

Using Numerical Simulation Tools to Assist the Development of a High Stability Low NOx Industrial Burner

2012 ◽  
Author(s):  
Ainan Bao ◽  
Dexin Wang ◽  
William Liss
Keyword(s):  
Flue Gas ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Premixed Combustion ◽  
Nox Emission ◽  
Combustion Stability ◽  
Simulation Tool ◽  
Burner Design ◽  
Thermal Nox ◽  
Low Nox Emission

To achieve ultra low NOx emission as well as high efficiency for industrial burners, premixed or partial premixed combustion technology is becoming more attractive than flue gas recirculation approaches, which tend to cause low combustion stability and low energy use efficiency. A well designed premixed combustion system can achieve lower and more uniform combustion zone temperatures thus resulting in reduced thermal NOx generation. A multi-stage premixed industrial scale gas burner with oil backup capability has been developed by the authors, with the assistance from CFD simulation. By using staged combustion, combustion heat release is better distributed into a larger volume to avoid high peak flame temperature zone to occur. By using a primary stage combustion with a fuel rich flame and a hot high emissive metallic chamber wall, the burner combustion stability is ensured. The CFD tool was used to simulate and optimize the whole burner combustion and heat transfer process, with proper fluid dynamics and reaction models for this full size burner development. With the CFD efforts, the final burner design can achieve a very uniform temperature field, with peak flame temperatures below 1650°C, therefore thermal NOx generation is minimized. The numerical results show that this new gas-fired burner can achieve high efficiency with low NOx emission. Using the CFD simulation tool, the burner global parameters, such as its peak flame temperatures, its exhaust flue gas temperatures, and its NOx concentration distributions, have been studied under different burner operation conditions, e.g., different excess air levels, different burner firing rates, and different mixture inlet temperatures. The CFD simulation tool has been proved a good assistance for the burner design, as well as the burner performance optimization.

Simulationsmodell zur Temperaturbestimmung beim Bohren*/Simulation model to determine temperature during drilling - Analytical simulation of temperature distribution during axial near-surface drilling

2017 ◽  
Vol 107 (10) ◽  
pp. 761-766
Author(s):  
M. Volz ◽  
E. Prof. Abele ◽  
F. Donig
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Simulation Model ◽  
Surface Boundary ◽  
Near Surface ◽  
Workpiece Surface ◽  
Analytical Simulation ◽  
Surface Boundary Condition

Ziel ist die simulative Bestimmung der Temperatur beim axial-oberflächennahen Bohren. Dazu wird ein analytisches Simulationsmodell mit dem Ansatz von Carslow und Jaeger implementiert. Es werden Randbedingungen für adiabate Werkstückoberflächen definiert, um die Auswirkungen auf die Temperaturverteilung zu simulieren. Das Simulationsmodell wird anhand experimenteller Bohrversuche unter Verwendung der Infrarot-Thermographie validiert, um anschließend den Temperaturverlauf im Werkstück zu simulieren.   An analytical simulation model based on the approach of Carslow and Jaeger is used to calculate the temperature field during drilling. In this case, the workpiece surface boundary condition is constrained to be adiabatic. The simulation model is validated by experimental data by means of infrared thermography. Finally, the simulation model is used to calculate the temperature during axial near-surface drilling.

Experimental and CFD Simulation of a Bubble Column

2012 ◽  
Vol 727-728 ◽  
pp. 1824-1829 ◽  
Author(s):  
J.A. Ribeiro ◽  
A.S. Reis ◽  
P.S. Avendaño ◽  
C.H. Ataíde ◽  
Marcos A.S. Barrozo
Keyword(s):  
Experimental Data ◽  
Computational Model ◽  
Chemical Engineering ◽  
Cfd Simulation ◽  
Bubble Column ◽  
Cfd Simulations ◽  
Multiphase Mixture ◽  
Liquid Phases ◽  
Large Application ◽  
Different Diameters

The numerical simulation in fluid mechanics has large application in chemical engineering. The objective of the present work is the analyze of a computational model for the fluid dynamics behaviour of a bubble column of the geometry cylindrical non regular with multiphase mixture. Experimental data and CFD results of the hydrodynamics of gaseous and liquid phases have been compared. Five different diameters of bubbles have been used in the CFD simulations. The comparisons between CFD simulations and experimental data show that the Eulerian-Eulerian approach provides a computational model that represents the process satisfactorily.

CFD Simulation of Gas-Liquid Flows in a Reactor Stirred by Dual Rushton Turbines

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Gopal R. Kasat ◽  
Aniruddha B. Pandit ◽  
V. V Ranade
Keyword(s):  
Experimental Data ◽  
Computational Model ◽  
Reference Frames ◽  
Cfd Simulation ◽  
Fluid Model ◽  
Flow Regimes ◽  
Stirred Vessel ◽  
Stirred Reactor ◽  
Commercial Solver ◽  
Liquid Flows

In the present work, we have simulated gas-liquid flows in a tall stirred reactor equipped with dual Rushton turbines. A two fluid model along with the standard k-? turbulence model and modified drag coefficient, (proposed by Khopkar & Ranade, 2006) accounting for the effect of bulk turbulence, was used to simulate the dispersed gas-liquid flow in a stirred reactor. The multiple reference frames (MRF) approach was used to simulate impeller rotation in a fully baffled reactor. The computational model was mapped on to a commercial solver FLUENT 6.2 (of Fluent Inc. USA). The model was used to simulate three distinct flow regimes in a gas-liquid stirred reactor: L33-VC (lower impeller-upper impeller), S33-VC and VC-VC. The model predictions were compared with the published experimental data of Bombac & Zun (2000). The predicted results show good agreement with the experimental data for all the three flow regimes. The computational model presented in this work would be useful for simulating different flow regimes in a gas-liquid stirred vessel.

scholarly journals Ignition Vulnerabilities of Combustibles around Houses to Firebrand Showers: Further Comparison of Experiments

2021 ◽  
Vol 13 (4) ◽  
pp. 2136
Author(s):  
Sayaka Suzuki ◽  
Samuel L. Manzello
Keyword(s):  
Experimental Data ◽  
Thermal Radiation ◽  
Driving Force ◽  
Fire Spread ◽  
Significant Problem ◽  
Next Generation ◽  
Similar Time ◽  
Comparison Of Experiments ◽  
Fire Front ◽  
Wui Fires

Wildland fires and wildland urban-interface (WUI) fires have become a significant problem in recent years. The mechanisms of home ignition in WUI fires are direct flame contact, thermal radiation, and firebrand attack. Out of these three fire spread factors, firebrands are considered to be a main driving force for rapid fire spread as firebrands can fly far from the fire front and ignite structures. The limited experimental data on firebrand showers limits the ability to design the next generation of communities to resist WUI fires to these types of exposures. The objective of this paper is to summarize, compare, and reconsider the results from previous experiments, to provide new data and insights to prevent home losses from firebrands in WUI fires. Comparison of different combustible materials around homes revealed that wood decking assemblies may be ignited within similar time to mulch under certain conditions.

scholarly journals Minimum Number of Experimental Data for the Thermal Characterization of a Hot Water Storage Tank

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4741
Author(s):  
María Gasque ◽  
Federico Ibáñez ◽  
Pablo González-Altozano
Keyword(s):  
Experimental Data ◽  
Water Temperature ◽  
Temperature Profile ◽  
Storage Tank ◽  
Water Storage ◽  
Hot Water ◽  
Experimental Temperature ◽  
Inlet Temperature ◽  
Water Storage Tank ◽  
Minimum Number

This paper demonstrates that it is possible to characterize the water temperature profile and its temporal trend in a hot water storage tank during the thermal charge process, using a minimum number of thermocouples (TC), with minor differences compared to experimental data. Four experimental tests (two types of inlet and two water flow rates) were conducted in a 950 L capacity tank. For each experimental test (with 12 TC), four models were developed using a decreasing number of TC (7, 4, 3 and 2, respectively). The results of the estimation of water temperature obtained with each of the four models were compared with those of a fifth model performed with 12 TC. All models were tested for constant inlet temperature. Very acceptable results were achieved (RMSE between 0.2065 °C and 0.8706 °C in models with 3 TC). The models were also useful to estimate the water temperature profile and the evolution of thermocline thickness even with only 3 TC (RMSE between 0.00247 °C and 0.00292 °C). A comparison with a CFD model was carried out to complete the study with very small differences between both approaches when applied to the estimation of the instantaneous temperature profile. The proposed methodology has proven to be very effective in estimating several of the temperature-based indices commonly employed to evaluate thermal stratification in water storage tanks, with only two or three experimental temperature data measurements. It can also be used as a complementary tool to other techniques such as the validation of numerical simulations or in cases where only a few experimental temperature values are available.

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