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Description
Title: | Transient model of preheating a submerged entry nozzle |
Author(s): | Li, Yonghui |
Advisor(s): | Thomas, Brian G. |
Department / Program: | Mechanical Sci & Engineering |
Discipline: | Mechanical Engineering |
Degree Granting Institution: | University of Illinois at Urbana-Champaign |
Degree: | M.S. |
Genre: | Thesis |
Subject(s): | Preheating
Nozzle Refractory Combustion Fuel component Torch configuration Flame temperature Thermal conductivity Insulation Visual Basic Application (VBA) Heat Conduction |
Abstract: | Adequate preheating of the submerged entry nozzle (SEN) is important to avoid problems such as thermal cracks and skulling, and depends on torch configuration, fuel, SEN geometry and other factors. A steady-state axisymmetric computational model of the flame, combustion reactions, and air entrainment has been combined with a transient model of heat transfer in the refractory walls to simulate the SEN preheating process. The model predictions match with experimental measurements of preheating with a natural-gas torch, including temperature profile across the flame, temperature histories measured inside the SEN wall, the flame shape, and the SEN outer wall temperature distribution. A Simple spread-sheet models is introduced to predict approximate flame temperature, heat transfer coefficients thermal properties, and SEN temperatures during preheating, given the air entrainment predicted from the 2D Combustion Model. Another spread-sheet model predicts SEN wall temperature histories during preheating, cool-down, and casting processes, with different temperature-dependent SEN material properties, geometries, initial conditions, and boundary conditions. The results reveal the times required to reach adequate preheating temperature and thermal patterns during each process. A parametric study of combustion during preheating found that positioning the torch at a proper distance above the SEN top, including an insulation layer and increasing refractory conductivity all increase SEN temperature and shorten preheating time. |
Issue Date: | 2015-01-21 |
URI: | http://hdl.handle.net/2142/72875 |
Rights Information: | Copyright 2014 Yonghui Li |
Date Available in IDEALS: | 2015-01-21 |
Date Deposited: | 2014-12 |
This item appears in the following Collection(s)
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Dissertations and Theses - Mechanical Science and Engineering
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Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois