14 LI Yonghui Heat Transfer In SEN During Preheating Ppt.ppt
CCC ANNUAL REPORTUIUC, August 18, 2011Modeling Heat Transfer in SENduring PreheatingYonghui LiBrian G. ThomasDepartment of Mechanical Science and EngineeringUniversity of Illinois at Urbana-ChampaignObjectives1) Validate Singh VBA SEN heat-transfermodel with analytical solutiong VBA SEN model with2)) Validate Singhmeasurements conducted duringppreheatingg3) Improve and apply validated models tostudy SEN heat transfer duringpreheating, cool-down, and castingUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li2
Singh VBA Spreadsheet Model of SENUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li3Singh’s SEN Model - Main pageUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li4
Governing equation & boundaryconditions for test problemGoverning Heat Transfer Equation3-D Schematic of SENBoundary conditionsUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li5Test problem in Singh modelIn the nozzle wall there is only one layer with test material.1-D Schematic of Singh VBA modelDiscretized heat transfer equations for Singh modelInterior nodesBoundary nodesInterface nodesUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li6
Test problem conditionsTest conditionsInput valueInside temperature600 Outside temperature20 Inside heat transfer coefficient70 W/m2KOutside heat transfer coefficient20 W/m2KInside radius40 mmOutside radius80 mmHeat conductivity20 W/m KDensity2460 kg/m3Specific heat1500 J/kg KUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li7Test Problem in Abaqust 120 min.Tinitial 20 Cho 20 W/m2KTo 20 C*Other surfaces arehi 70 W/m2KTi 600 Cinsulatedk 20 W/mKρ 2460 kg/m3Cp 1500 J/kgKMesh schematic of Abaqus Model** form Hyoung-Jun Lee, Test Abaqus model Hyoung-jun Lee, 2011, 07University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li8
Comparison of Abaqus and Singh-modelComparison of two models450.0Tempperature(degC)400.0I id (AbInside(Abaqus andd SiSingh)h)350.0300.0250.0Outside (Abaqus and Singh)200.0150.0100.050.00.00100020003000Mesh refinement studySingh’snumberof nodes5 nodes 00070008000Preheat time(s)Error ofinsideAbaqusoutside*Singhoutside*Error ofoutside59002100*temperature at 120mins at SEN surfaceUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li9SEN Preheating Preheating is by fuel and oxygen combustion; product gas mixed with entrained air flows intoSEN, which increases nozzle wall temperature.P h t SchematicPreheatS htiP hPreheatSSet-up**Thermocouplesare installed atthe hottestregion of theSEN body.* from PB10 SEN Temperature Data for CCC Heat Flow Model,Magnesita Refractories Research reportUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li10
Preheatingg Experimentp The preheating mechanism is the fuel and oxygen combustion, then the product gas mixed withair flows into SEN, which make SEN temperature increased.Infra-red image of SEN*Gas temperature across SEN*Average temperature 1262 Based on the gas composition and no air dilution, the flame temperature was calculated as3100 . The ggas temperaturepacross the SEN shows the actual flame temperaturepwas pprobablyyonly realized at the burner tip.** from PB10 SEN Temperature Data for CCC Heat Flow Model, Magnesita RefractoriesResearch reportUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li11Refractory Temperature Dependent Properties*Material Alumina Thermo-propertiesGlaze Material Thermo-properties* from Rob Nunnington, Magnesita RefractoriesUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li12
Sensitivity Study - IntroductionApproach of Sensitivity Analysis Choose standard conditions of all variables to get standard result For each variable, choose a reasonable engineering estimate of its mostextreme value For each variable, calculate a new result using its new value while keepingthe same constant standard conditions for all of the others Compare the new results with the standard resultWhy need Sensitivity analysis?*TTo ddetermineti whichhi h variablesi bl are mostt iimportantt tUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li13Sensitivity Study of Steady state ModelWhat value of thesethree variables inSingh VBA Model areneed to matchmeasurement result?The mostiimportantvariablesEstimated uncertainty ofgas temperature:Highest temperaturelowest temperature 1432 885 547 1432-885 547 EstimatedNewStandard(372 )Independent variableStandarduncertaintyresultErrorGas Temperature600 547 704 332 External Temperature20 -10 368 -4 70W/m2K-10 W/m2K352 -20 20 W/m2K-10 W/m2K457 86 20W/mK-5 W/mK369 -3 Internal convectioncoefficientExternal convectioncoefficientHeat conductivityUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Big error!Yonghui Li14
Flame Temperature Model—Main PageMain Page ** form Flame Temperature Model, Varun K. Singh, 2010University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li15Use Flame Temperature Model to calculateproduct temperatureppThe Stoichiometric reaction for methane is :CH4 2O2 2*79/21 N2 CO2 H2O 2*79/21 N2AverageproductsTemperatureis 1262 。University of Illinois at Urbana-Champaign Adjust AirEntrainment tomatch 1262 Metals Processing Simulation Lab Yonghui Li16
Use Flame Temperature Model to calculateconvection coefficientIt should notice that not all the product gas flow into the SEN. Most part of thegas flow from the outside SEN. In a reasonable domain, I assume 2% gas flowinto the SEN to get the reasonable flow rate and gas velocity inside the SENSEN.Heat Transfer Coefficient Calculation Model*Put these twocoefficients intoSingh HeatTransfer ModelAre all these inputwill make Singh HeatTransfer Model ‘spredict temperaturematchatc withtmeasurement?*form Flame Temperature Model, Varun K. Singh, 2010University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li17Results of Singh VBA Model Comparison withMeasurementsInput of Singh Heat Transfer ModelUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li18
Other possible matched casesIn all four cases, Singh VBA SEN heat-transfer modelmatched with measurement data very well.More work is needed to find the most realistic case.GasTemperature( )Internal forcedconvectioncoefficient(W/m2K)External forcedconvectioncoefficient(W/m2K)Case 1750477Case 2900335Case 31000309Case 41262218University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li19Conclusion Through Abaqus Test problem, Singh’s VBA heat transfer Modelworks well at one layer with constant material properties. Through Sensitivity Analysis, gas product temperature, internaland external convection heat transfer coefficient are the threemost important variables affect heat transfer across SEN. Basedon sensitivity analysis, we find the major variables to matchSingh heat transfer Model with measurementmeasurement. By using Flame Temperature Model, users can predict internaland external heat transfer coefficientcoefficient. Predicted by this modelmodel,2221W/m K for internal and 7.55 W/m K for external work very wellto match with measurement temperature.University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li20
Acknowledgement Continuous Casting Consortium(LWB Refractories ,ABB, Arcelor-Mittal, Baosteel,Corus, Nucor Steel, Nippon Steel, Postech, Posco,ANSYS-Fluent.) Rob Nunnington,Nunnington LWB Refractories Graduate students:- Hyoung-JunygLeeUniversity of Illinois at Urbana-Champaign Metals Processing Simulation Lab Yonghui Li21
Singh heat transfer Model with measurementSingh heat transfer Model with measurement. By using Flame Temperature Model, users can predict internal and external heat transfer coefficient Predicted by this modeland external heat transfer coefficient. Predicted by this model, 21W/m2K for internal and 7.55 W/m2K for external work very well
Basic Heat and Mass Transfer complements Heat Transfer,whichispublished concurrently. Basic Heat and Mass Transfer was developed by omitting some of the more advanced heat transfer material fromHeat Transfer and adding a chapter on mass transfer. As a result, Basic Heat and Mass Transfer contains the following chapters and appendixes: 1.
Feature Nodes for the Heat Transfer in Solids and Fluids Interface . . . 331 The Heat Transfer in Porous Media Interface 332 Feature Nodes for the Heat Transfer in Porous Media Interface . . . . 334 The Heat Transfer in Building Materials Interface 338 Settings for the Heat Transfer in Building Materials Interface . . . . . 338
Both temperature and heat transfer can change with spatial locations, but not with time Steady energy balance (first law of thermodynamics) means that heat in plus heat generated equals heat out 8 Rectangular Steady Conduction Figure 2-63 from Çengel, Heat and Mass Transfer Figure 3-2 from Çengel, Heat and Mass Transfer The heat .
Holman / Heat Transfer, 10th Edition Heat transfer is thermal energy transfer that is induced by a temperature difference (or gradient) Modes of heat transfer Conduction heat transfer: Occurs when a temperature gradient exists through a solid or a stationary fluid (liquid or gas). Convection heat transfer: Occurs within a moving fluid, or
Young I. Cho Principles of Heat Transfer Kreith 7th Solutions Manual rar Torrent Principles.of.Heat.Transfer.Kreith.7th.Sol utions.Manual.rar (Size: 10.34 MB) (Files: 1). Fundamentals of Heat and Mass Transfer 7th Edition - Incropera pdf. Principles of Heat Transfer_7th Ed._Frank Kreith, Raj M. Manglik Principles of Heat Transfer. 7th Edition
1 INTRODUCTION TO HEAT TRANSFER AND MASS TRANSFER 1.1 HEAT FLOWS AND HEAT TRANSFER COEFFICIENTS 1.1.1 HEAT FLOW A typical problem in heat transfer is the following: consider a body “A” that e
J. P. Holman, “Heat Transfer . Heat transfer (or heat) is thermal energy in transit due to a spatial temperature difference. Whenever a temperature difference exists in a medium or between media, heat transfer must occur. As shown in Figure 1.1, we refer to different types of heat transfer processes as
cited as the Civil Procedure Rules 1998— PART 1 OVERRIDING OBJECTIVE Contents of this Part The overriding objective Rule 1.1 Application by the court of the overriding objective Rule 1.2 Duty of the parties Rule 1.3 Court’s duty to manage cases Rule 1.4 The overriding objective 1.1.—(1) These Rules are a new procedural code with the overriding objective of enabling the court to deal with .
