The Application of a Two-Dimensional Zone Model to the Design and Control of a Continuously Operated, Gas-Fired Furnace

2002 ◽  
Author(s):  
Sara A. C. Correia ◽  
John Ward
Keyword(s):  
Dynamics Simulation ◽  
Relative Mass ◽  
Zone Model ◽  
Two Dimensional ◽  
Furnace Design ◽  
Simplified Approach ◽  
Flow Models ◽  
Discharge Temperature ◽  
Wide Range ◽  
And Control

This paper describes the development of a two-dimensional zone model to predict the throughput and thermal performance of a continuously operated gas-fired furnace heating steel bars to a nominal discharge temperature of 1250°C. Ultimately the model is intended to be a tool which can be used for the design and control of industrial furnaces. Consequently relatively short computing times are necessary and this was achieved by employing an isothermal computational fluid dynamics simulation to estimate the relative mass flows, and hence enthalpy flows to or from adjacent volume zones in the overall model. This simplified approach, which utilises a single “once off” isothermal computation of the flows, was considered to be adequate since isothermal flow models have been used successfully in the past to study the flow related behaviour of combustion systems. The coupling of a multi-zone model with a single “once off” isothermal computation of the flows enables a wide range of furnace design modifications to be studied quickly and easily. To illustrate the potential use of the model in a furnace design application, it was then used to investigate the effects of inclining the burners downwards towards the load as well as those associated with increasing the length of the furnace.

Numerical Prediction of the Transient Operation of a Gas-Fired Reheating Furnace

2000 ◽  
Author(s):  
Sara A. C. Correia ◽  
John Ward ◽  
João L. V. A. Sousa
Keyword(s):  
Thermal Radiation ◽  
Dynamics Simulation ◽  
Relative Mass ◽  
Small Scale ◽  
Zone Model ◽  
Zone Method ◽  
Reheating Furnace ◽  
Simplified Approach ◽  
Discharge Temperature ◽  
Mass Flow Rates

Abstract The well-known “zone method”, treats thermal radiation in an enclosure in a global manner so that reliable estimates of this mode of heat transfer can be obtained in systems such as gas-fired furnaces. Consequently the paper employs a two-dimensional thermal radiation model in which both the height and length of the furnace was divided into surface and volume zones. An isothermal computational fluid dynamics simulation was used to estimate the relative mass flow rates, and hence enthalpy flows, into or out of each volume zone. This simplified approach was considered to provide a reasonable estimate of the appropriate inter-zone mass flows since the use of small-scale experimental, near ambient temperature models has been shown in the past to give useful data on flow related behaviour of combustion systems. The computing times resulting from the coupling of a multi-zone model with a single isothermal computation of the flows are relatively short so that the transient performance of the reheating furnace can be analysed. The mathematical model was thus used to predict the fuel consumptions and load temperatures in a gas-fired furnace heating steel bars to a nominal discharge temperature of 1250°C over a typical transient operating period of 8 hours including the start-up from cold. The influences of burner geometry as well as the effects of changes to the value of the roof set point temperature which was used to control the thermal input to the burners were studied. The effects of varying the position of the roof temperature control sensor relative to the burners and of changes in the roof construction were also investigated.

The Application of Multi-Zone Thermal Radiation Models to Investigate the Energy Efficiency of a Metal Reheating Furnace Under Start Up Conditions

1999 ◽  
Author(s):  
John Ward ◽  
Sara A. C. Correia ◽  
João L. V. A. Sousa
Keyword(s):  
Combustion Products ◽  
Furnace Chamber ◽  
Zone Model ◽  
Two Dimensional ◽  
Heating Rates ◽  
Zone Method ◽  
Discharge Temperature ◽  
Start Up ◽  
Steel Bars ◽  
Industrial Heating

Abstract The zone method of radiation analysis has been widely used in mathematical models of a range of industrial heating processes. This paper is thus concerned with the use of a two-dimensional, multi-zone model to predict fuel consumptions, heating rates and load temperatures following the “cold start up” of a gas-fired furnace heating steel bars to a nominal discharge temperature of 1250°C. The model takes into account variations in the flows of the combustion products and in particular examines the influence of the re-circulation of these hot gases within the furnace chamber. The predictions of this complex two-dimensional model are compared with those of a one-dimensional so-called “long furnace model” to illustrate the differences resulting from the use of a more sophisticated multi-zone model.

Development of a Spectral Radiation Model to Predict the Transient Performance of a Metal Reheating Furnace

2009 ◽  
Author(s):  
J. Ward ◽  
C. K. Tan ◽  
R. J. Tucker
Keyword(s):  
Combustion Products ◽  
Thermal Design ◽  
Zone Model ◽  
Spectral Variation ◽  
Transient Performance ◽  
Zone Method ◽  
Discharge Temperature ◽  
Radiation Properties ◽  
Wide Range ◽  
High Emissivity

The use of computational fluid dynamics for simulation of combustion processes has made significant advances in recent years particularly for the design of individual burners and the prediction of pollutant formation and emission. However, the computational requirements of these models can still be too great for overall furnace thermal design purposes particularly if the transient performance is required. Thermal radiation is usually the dominant mode of heat transfer to the load or stock in industrial fuel-fired furnaces since the contribution of convection is relatively small. Thus prediction of the thermal performance of a furnace requires an accurate calculation of the complex radiation interchange between the surfaces and the combustion products. This can be achieved by the so-called Hottel zone method of radiation analysis and as a result this method has been applied to a wide range of industrial heating processes. The method sub-divides the non-isothermal furnace enclosure into a series of isothermal volume and surface zones and energy balances are then formulated and solved simultaneously for each zone. The computational demands are modest so that the process can be repeated successively throughout a period of furnace operation to simulate the transient behaviour of the system. However in these models all the surfaces are usually assumed to be grey and the radiation properties of the combustion products are normally represented by a mixture of grey and clear gases. These assumptions can lead to errors in the predictions, in applications such as the installation of high emissivity coatings on the furnace lining, where it is necessary to allow for the spectral variation in surface emissivity and the banded nature of the radiation properties of carbon dioxide and water vapour in the combustion gases. Consequently the proposed paper describes the development of “spectral” zone model, which takes these effects into account, to predict the transient performance of a furnace heating steel bars to a discharge temperature of 1200°C. The model also allows for broadening of the spectral bands with changes in the temperature of the combustion products. The work differs from that in previous papers on this type of model, which have been confined to steady-state simulations and do not allow for broadening. Finally the model is applied to investigate the effect of coating the refractory lining of the furnace with high emissivity materials.

scholarly journals An Extended Assessment of Fluid Flow Models for the Prediction of Two-Dimensional Steady-State Airfoil Aerodynamics

2015 ◽  
Vol 2015 ◽  
pp. 1-31 ◽  
Author(s):  
José F. Herbert-Acero ◽  
Oliver Probst ◽  
Carlos I. Rivera-Solorio ◽  
Krystel K. Castillo-Villar ◽  
Santos Méndez-Díaz
Keyword(s):  
Fluid Flow ◽  
Turbulence Models ◽  
Sensitivity Analyses ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Surface Shear ◽  
Flow Models ◽  
Wide Range ◽  
Solution Methods ◽  
Analysis Application

This work presents the analysis, application, and comparison of thirteen fluid flow models in the prediction of two-dimensional airfoil aerodynamics, considering laminar and turbulent subsonic inflow conditions. Diverse sensitivity analyses of different free parameters (e.g., the domain topology and its discretization, the flow model, and the solution method together with its convergence mechanisms) revealed important effects on the simulations’ outcomes. The NACA 4412 airfoil was considered throughout the work and the computational predictions were compared with experiments conducted under a wide range of Reynolds numbers (7e5≤Re≤9e6) and angles-of-attack (-10°≤α≤20°). Improvements both in modeling accuracy and processing time were achieved by considering the RS LP-S and the Transition SST turbulence models, and by considering finite volume-based solution methods with preconditioned systems, respectively. The RS LP-S model provided the best lift force predictions due to the adequate modeling of the micro and macro anisotropic turbulence at the airfoil’s surface and at the nearby flow field, which in turn allowed the adequate prediction of stall conditions. The Transition-SST model provided the best drag force predictions due to adequate modeling of the laminar-to-turbulent flow transition and the surface shear stresses. Conclusions, recommendations, and a comprehensive research agenda are presented based on validated computational results.

A SECTION APPROACH TO A TRAFFIC FLOW MODEL ON NETWORKS

2013 ◽  
Vol 24 (05) ◽  
pp. 1350018 ◽  
Author(s):  
ARVIND KUMAR GUPTA
Keyword(s):  
Traffic Flow ◽  
Road Networks ◽  
Simulated Data ◽  
Simplified Approach ◽  
Flow Models ◽  
Special Boundary Condition ◽  
Real Time Traffic ◽  
Traffic Flow Models ◽  
Section Model ◽  
And Control

The development of real time traffic flow models for urban road networks is of paramount importance for the purposes of optimizing and control of traffic flow. Motivated by the modeling of road networks in last decade, this paper proposes a different and simplified approach, known as section approach to model road networks in the framework of macroscopic traffic flow models. For evaluation of the traffic states on a single road, an anisotropic continuum GK-model developed by [Gupta and Katiyar, J. Phys. A38, 4069 (2005)] is used as a single-section model. This model is applied to a two-section single lane road with points of entry and exits. In place of modeling the effect of off- and on-ramps in the continuity equation, a set of special boundary condition is taken into account to treat the points of entry and exit. A four-section road network comprised of two one-lane roads is also modeled using this methodology. The performances of the section approaches are investigated and obtained results are demonstrated over simulated data for different boundary conditions.

THE SOME QUESTIONS OF AUTONOMOUS MOTION AND MANAGEMENT OF LAND-MOBILE ROBOTIC COMPLEXES FOR UKRAINIAN GROUND FORCESE

2019 ◽  
pp. 53-58
Author(s):  
О. Кravchuk ◽  
V. Symonenkov ◽  
I. Symonenkova ◽  
O. Hryhorev
Keyword(s):  
Large Scale ◽  
Armed Forces ◽  
Distributed Information ◽  
Wide Range ◽  
Highly Effective ◽  
Information Management Systems ◽  
Robotic Devices ◽  
Principles And Standards ◽  
And Control ◽  
The Eu

Today, more than forty countries of the world are engaged in the development of military-purpose robots. A number of unique mobile robots with a wide range of capabilities are already being used by combat and intelligence units of the Armed forces of the developed world countries to conduct battlefield intelligence and support tactical groups. At present, the issue of using the latest information technology in the field of military robotics is thoroughly investigated, and the creation of highly effective information management systems in the land-mobile robotic complexes has acquired a new phase associated with the use of distributed information and sensory systems and consists in the transition from application of separate sensors and devices to the construction of modular information subsystems, which provide the availability of various data sources and complex methods of information processing. The purpose of the article is to investigate the ways to increase the autonomy of the land-mobile robotic complexes using in a non-deterministic conditions of modern combat. Relevance of researches is connected with the necessity of creation of highly effective information and control systems in the perspective robotic means for the needs of Land Forces of Ukraine. The development of the Armed Forces of Ukraine management system based on the criteria adopted by the EU and NATO member states is one of the main directions of increasing the effectiveness of the use of forces (forces), which involves achieving the principles and standards necessary for Ukraine to become a member of the EU and NATO. The inherent features of achieving these criteria will be the transition to a reduction of tasks of the combined-arms units and the large-scale use of high-precision weapons and land remote-controlled robotic devices. According to the views of the leading specialists in the field of robotics, the automation of information subsystems and components of the land-mobile robotic complexes can increase safety, reliability, error-tolerance and the effectiveness of the use of robotic means by standardizing the necessary actions with minimal human intervention, that is, a significant increase in the autonomy of the land-mobile robotic complexes for the needs of Land Forces of Ukraine.

Aromatic Volatile Composition of Celery and Celeriac Cultivars

HortScience ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 556-559 ◽  
Author(s):  
Fredy Van Wassenhove ◽  
Patrick Dirinck ◽  
Georges Vulsteke ◽  
Niceas Schamp
Keyword(s):  
Volatile Compounds ◽  
Chromatographic Method ◽  
Apium Graveolens ◽  
Volatile Components ◽  
Two Dimensional ◽  
Qualitative Composition ◽  
Volatile Composition ◽  
Wide Range ◽  
Gas Chromatographic Method ◽  
Identification And Quantification

A two-dimensional capillary gas chromatographic method was developed to separate and quantify aromatic volatiles of celery in one analysis. The isolation, identification, and quantification of the volatile compounds of four cultivars of blanching celery (Apium graveolens L. var. dulce) and six cultivars of celeriac (Apium graveolens L. var. rapaceum) are described. The qualitative composition of Likens-Nickerson extracts of both cultivars is similar. The concentration of terpenes and phthalides, the key volatile components, found in various cultivars of both celery and celeriac varied over a wide range.

Thin structure of heterogeneous and multiphase fluid flows

2012 ◽  
Vol 9 (1) ◽  
pp. 175-180
Author(s):  
Yu.D. Chashechkin
Keyword(s):  
Large Scale ◽  
Fundamental System ◽  
Fluid Flows ◽  
Regular Solutions ◽  
Flow Models ◽  
Group Methods ◽  
Wide Range ◽  
Thin Structure ◽  
Multiphase Fluid ◽  
Complete Solutions

According to the results of visualization of streams, the existence of structures in a wide range of scales is noted: from galactic to micron. The use of a fundamental system of equations is substantiated based on the results of comparing symmetries of various flow models with the usage of theoretical group methods. Complete solutions of the system are found by the methods of the singular perturbations theory with a condition of compatibility, which determines the characteristic equation. A comparison of complete solutions with experimental data shows that regular solutions characterize large-scale components of the flow, a rich family of singular solutions describes formation of the thin media structure. Examples of calculations and observations of stratified, rotating and multiphase media are given. The requirements for the technique of an adequate experiment are discussed.

scholarly journals Information and information resources in COVID-19: Awareness, control, and prevention

2021 ◽  
pp. 096100062110165
Author(s):  
Mohammadhiwa Abdekhoda ◽  
Fatemeh Ranjbaran ◽  
Asghar Sattari
Keyword(s):  
Low Cost ◽  
Information Resources ◽  
Age And Gender ◽  
Use Of Resources ◽  
Strategic Approach ◽  
Wide Range ◽  
Data Collection Instrument ◽  
Control And Prevention ◽  
And Gender ◽  
And Control

This study was conducted with the aim of evaluating the role of information and information resources in the awareness, control, and prevention of COVID-19. This study was a descriptive-analytical survey in which 450 participants were selected for the study. The data collection instrument was a researcher-made questionnaire. Descriptive and inferential statistics were used to analyze the data through SPSS. The findings show that a wide range of mass media has become well known as information resources for COVID-19. Other findings indicate a significant statistical difference in the rate of using information resources during COVID-19 based on age and gender; however, this difference is not significant regarding the reliability of information resources with regard to age and gender. Health information has an undisputable role in the prevention and control of pandemic diseases such as COVID-19. Providing accurate, reliable, and evidence-based information in a timely manner for the use of resources and information channels related to COVID-19 can be a fast and low-cost strategic approach in confronting this disease.

Effects of active crowder size and activity-crowding coupling on polymer translocation

Soft Matter ◽  
2020 ◽  
Author(s):  
Fei Tan ◽  
Ying Chen ◽  
Nanrong Zhao
Keyword(s):  
Langevin Dynamics ◽  
Dynamics Simulation ◽  
Biological Processes ◽  
Two Dimensional ◽  
Complex Environments ◽  
Polymer Translocation ◽  
Langevin Dynamics Simulation

Polymer translocation in complex environments is crucially important to many biological processes in life. In the present work, we adopted two-dimensional Langevin dynamics simulation to study the forced and unbiased...

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