Continuous Casting Nozzle Deflector Flow Symmetry
Solution Overview
Problem
In continuous casting, existing nozzles produce uneven flow paths of liquid steel into the mold, leading to surface defects, nozzle clogging, and inefficient steel quality due to turbulent flow and uneven distribution of mold flux, resulting in increased thermal stresses and frequent nozzle changes.
Innovation Solution
A deflector is integrated into the continuous casting nozzle at the bottom portion to redirect the liquid steel flow centrally within the bore, using a tapered design and ports aligned along a specific plane to ensure symmetrical flow paths, reducing nozzle clogging and improving fluid dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional nozzle with parallel bore walls is used, then the nozzle structure is simple, but the liquid steel flow paths become uneven and biased, producing surface defects and requiring frequent nozzle changes
Solution Approach 1:
The nozzle bore is segmented into multiple zones with different wall angles: an upper portion with a first angle, a middle portion with a second angle, and a lower portion with a third angle. This segmentation allows each zone to perform a specific function in controlling flow development, achieving uniform flow paths while maintaining manufacturing feasibility through defined geometric transitions.
Solution Approach 2:
Different sections of the bore walls are given different local geometric properties (different angles relative to the longitudinal axis). The upper portion has a larger angle to handle initial flow, the middle portion has a reduced angle for flow stabilization, and the lower portion has a specific angle for optimal discharge. This local differentiation of geometric quality enables precise control over flow path uniformity.
2Productivity
If the nozzle operates for extended periods, then productivity increases, but the nozzle becomes clogged with foreign particles, distorting flow paths and requiring nozzle replacement
Solution Approach 1:
The optimized bore geometry with specific angle progressions is designed beforehand to prevent flow distortion before it occurs. The gradual angle transitions are pre-configured to maintain flow attachment and prevent turbulence development, addressing potential clogging issues before they affect productivity by ensuring consistent flow paths throughout extended operation periods.
Solution Approach 2:
The bore design incorporates gradual angle transitions that act as a cushion against sudden flow disturbances. The middle portion with reduced angle and the lower portion with optimized angle create a progressive flow conditioning effect that cushions against the impact of foreign particles, preventing abrupt flow path distortions and extending nozzle service life.
3Manufacturing precision
If the liquid steel jet flows turbulently near the bore wall, then the nozzle structure remains simple, but the flow creates swirl and divides into uneven paths, reducing steel quality
Solution Approach 1:
The bore geometry employs asymmetric angle relationships relative to the longitudinal axis at different heights. The upper portion angle, middle portion angle, and lower portion angle are deliberately different to create a controlled asymmetric flow pattern that actually results in symmetric discharge at the ports. This controlled asymmetry in the bore geometry compensates for natural flow asymmetries and achieves flow path symmetry at the exit.
Solution Approach 2:
The solution moves from considering only the cross-sectional geometry to incorporating the longitudinal dimension with progressive angle changes. By adding the dimension of axial variation in wall angles, the design controls flow development through three-dimensional geometry, transforming a two-dimensional cross-section problem into a three-dimensional flow control solution that achieves symmetry.
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
The solution enhances the uniformity of steel flow, reduces surface defects, minimizes nozzle changes, and improves the quality and efficiency of the continuous casting process while lowering operational costs by maintaining consistent lubrication and heat transfer.
Implementation Method 1
the incoming turbulent steel jet (3) may flow near the wall of the bore (26) of the nozzle (20)
Implementation Method 2
a portion of a flow of liquid steel through the bore becomes detached from a surface of the bore to thereby redirect the flow of liquid steel toward the longitudinal axis
Data Source
AI summary
A continuous casting nozzle includes a deflector at a bottom portion of the nozzle having a bore extending through the deflector from an open end to a closed end along a longitudinal axis and a pair of ports extending through the deflector from the bore to an outer surface of the deflector. A diameter of the bore substantially rapidly decreases along the longitudinal axis above the pair of ports such that a portion of a flow of fluid through the deflector becomes detached from a surface of the bore to thereby redirect the flow of fluid toward the longitudinal axis prior to exiting through the pair of ports.