Transient model of preheating a submerged entry nozzle

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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Li, Yonghui

Contributors dc:contributor

• Thomas, Brian G.

• Fuel component
• Preheating
• Nozzle
• Refractory
• Combustion
• Torch configuration
• Flame temperature
• Thermal conductivity
• Insulation
• Visual Basic Application (VBA)
• Heat Conduction

Statement dc:rights

• Copyright 2014 Yonghui Li

Language dc:language

en

Handle dc:identifier

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

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/72875