Thin Slab Nozzle Geometry for High Flow Rate Control
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Solution Overview
Problem
Existing thin slab nozzles fail to adequately control high flow rates of molten metal into thin slab moulds, leading to unstable meniscus levels, turbulence, and increased wear, which affects the quality of the cast metal and the efficiency of the casting process.
Innovation Solution
A thin slab nozzle with a specific geometry that maintains a relatively constant total bore cross-sectional area from the inlet to the downstream portion, featuring a converging bore portion with a finite radius of curvature and a thin bore portion, ensuring smooth flow and minimizing turbulence, and a divider with a height at least twice that of the converging bore portion to streamline the flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the nozzle geometry is designed to handle high flow rates, then productivity increases, but flow control stability deteriorates
Solution Approach 1:
The nozzle bore is segmented into three distinct portions: an upstream portion with constant cross-sectional area, a converging portion that tapers the flow, and a thin bore portion that maintains constant area. This segmentation allows each section to perform its specific function - maintaining pressure, directing flow, and stabilizing output - thereby enabling high flow rates while preserving meniscus stability.
Solution Approach 2:
The invention changes the geometric parameters of the nozzle bore along its length. The cross-sectional area varies from constant in the upstream portion to decreasing in the converging portion, then constant again in the thin bore portion. These parameter changes optimize flow characteristics at different stages, allowing high productivity while maintaining flow control stability.
2Volume of moving object
If the converging bore portion has a small radius of curvature, then the nozzle can be more compact, but flow turbulence increases
Solution Approach 1:
The converging bore portion is designed with a finite radius of curvature rather than a sharp angle or zero curvature. This curved geometry allows the flow to transition smoothly from the upstream portion to the thin bore portion, reducing turbulence and eddy formation while maintaining a compact overall nozzle size.
3Reliability
If the thin bore portion is made longer, then flow control is improved, but the nozzle becomes more complex
Solution Approach 1:
The thin bore portion is located specifically at the downstream end of the nozzle where flow stabilization is most critical. By concentrating the constant cross-sectional area geometry in this specific location rather than throughout the entire nozzle, the design achieves improved flow control with minimal increase in overall complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design achieves stable and controlled flow patterns, reducing turbulence and meniscus level variations, thereby improving the quality of the cast metal and extending the service life of the nozzle, while enabling high-speed casting of thin slabs up to 10 tonnes per minute.
Implementation Method 1
The converging bore portion (50e) of height He... ensuring smooth flow and minimizing turbulence
Implementation Method 2
Flow of metal melt out of the tundish is driven by gravity through the pouring nozzle (1)
Data Source
AI summary
A thin slab nozzle contains a central bore extending downstream along longitudinal axis X1 from an inlet orifice at an upstream end. The central bore comprises an upstream bore portion with a height Ha, in communication with a converging bore portion of height He, in communication with a thin bore portion of height Hf ending at the upstream end of a divider, and first and second front ports separated from one another by the divider and coupled to the central bore portion at least partially at the converging bore portion. X2 is a transverse axis, normal to X1, along which the nozzle becomes thinner in a downstream portion. In a section of the thin slab nozzle along a symmetry plane Π1 defined by X1 and by X2, the bore wall of the converging bore portion is curved at all points, and Hf/He≤1.