Transient model of preheating a submerged entry nozzle

Li, Yonghui

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https://hdl.handle.net/2142/72875 Copy

Description

Title

Transient model of preheating a submerged entry nozzle

Author(s)

Li, Yonghui

Issue Date

2015-01-21

Director of Research (if dissertation) or Advisor (if thesis)

Thomas, Brian G.

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(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.

Graduation Semester

2014-12

Permalink

http://hdl.handle.net/2142/72875

Copyright and License Information

Copyright 2014 Yonghui Li

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