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Anewprocess has been developed for metal refining. This process involves the creation and dispersion of fine bubbles in molten metals by introducing inert or reactive gas into a turbulent flow region during metal transfer. The highly turbulent metal flow splits the gas into fine bubbles and results in good mixing betweenthe gas and molten metal phases. Theseconditions are ideal for contacting inclusions in the metal with the bubbles and subsequent flotation of the inclusions to the metal-slag interface wherethe inclusions are then absorbed by the covering siag layer. Dissolved gases, such as [H], [O], [N], in the metals are aiso transferred to the gas bubbles and removedfrom solution. The process can be retrofitted into existing process plants.The process concept has been demonstrated using a full-scale air/water model to The assembly of the slide gate, collector nozzle and shroud nozzle as shown in Fig, I is defined as ladle shroud system in this paper. Since the actual slide gate, collector nozzle and shroud pipe have the same inside diameters, the design of the model used in the present investigation has been simplified as shown in Fig. 3 Schematic diagram of pressure measurement ports and gas injection system. plus air, is in the range of O to 0.5. The gas was introduced through ports situated at various positions along the shroud pipe (Fig. 3) (Fig. 4). Thebubbles are so small andthe turbulence is so strong that it is difficult to identify individual gas bubbles in the dlspersion. When the water flow rate is reduced to 0.006m3/s (Fig. 5)

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In this paper, a new low-complexity method for two-dimensional (2D) direction-of-arrival (DOA) estimation is proposed. Based on a cross-correlation matrix formed from the L-shaped array, the proposed algorithm obtains the automatic pairing elevation and azimuth angles without eigendecomposition, which can avoid high computational cost. In addition, the cross-correlation matrix eliminates the effect of noise, which can achieve better DOA performance. Then, the theoretical error of the algorithm is analyzed and the Cramer–Rao bound (CRB) for the direction of arrival estimation is derived . Simulation results demonstrate that, at low signal-to-noise ratios (SNRs) and with a small number of snapshots, in contrast to Tayem’s algorithm and Kikuchi’s algorithm, the proposed algorithm achieves better DOA performance with lower complexity, while, for Gu’s algorithm, the proposed algorithm has slightly inferior DOA performance but with significantly lower complexity.

The pressure distribution and fluid flow profiles whithin the slide gate and shroud nozzle for the continuous casting of steel have been investigated using a full scale water model and a CFD (computational fluid dynamics) model. The water modelling has shown that a large quantity of air can be drawn into the liquid stream if there is any breakdown of the seals in the vicinity of the slide gate. The 3‐dimensional numerical solution for highly turbulent flow has predicted the pressure distribution and velocity profile within the slide gate and shroud. Based on the experimental and numerical modelling, it has been shown that cavitation can occur near the slide gate during ladle teeming. This can be a source for erosion of the refractories. Improvements to the design of the ladle shroud system are recommended.