Modeling of multiphase turbulent flow in continuous casting of steel

This thesis develops mathematical models of multiphase turbulent flow and investigates multiphase flow issues arising in the continuous casting process of steel through the application of the developed models. In the continuous casting of steel, argon gas injection at Upper Tundish Nozzle (UTN) wall or stopper tip is well known to decrease clogging and remove inclusions. Besides this intended gas injection, gas may be passively sucked into the system by negative pressure development inside of nozzles. The injected gas through these two paths is redistributed into small bubbles through complex gas redistribution processes, and the size distribution of the bubbles affects flow patterns as well as defect mechanisms in molds. Estimation of the exact amount of argon gas and size distribution of bubbles is crucial to optimize this multiphase flow manufacturing process for minimizing defects. In this thesis, existing multiphase flow models are reviewed first to model the multiphase flow issues discussed above. A new hybrid multiphase flow model Eulerian-Eulerian Discrete-Phase Model (EEDPM), which can estimate flow pattern and bubble interactions such as coalescence, breakup, shearing off and volumetric expansion is proposed. Also, a simple 1D pressure energy model is developed to estimate pressure distribution in multiphase flow systems with complex geometry. These newly developed models are applied to estimate the flow pattern associated with the locally time-varying bubble size distribution in the system. Parametric studies are implemented to understand effects of operating conditions on the bubble size distribution and the flow pattern. This work gives insights on mechanisms of bubble size evolution and furthermore, optimization of the continuous casting process with argon gas injection.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2018

Author dc:creator

• Yang, Hyunjin

Contributors dc:contributor

• Thomas, Brian G.
• Vanka, Surya P.
• Ruzic, David N.
• Smith, Kyle C.
• Brooks, Caleb

• BUBBLE SIZE DISTRIBUTION
• COALESCENCE
• BREAKUP
• SHEARING OFF
• VOLUMETRIC EXPANSION
• ASPIRATION

Statement dc:rights

• Copyright 2018 Hyunjin Yang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/101760

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/101760