| 1. |
- Hallgren, Line, et al.
(författare)
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Effect of nozzle swirl blade on flow pattern in runner during uphill teeming
- 2006
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 46:11, s. 1645-1651
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Tidskriftsartikel (refereegranskat)abstract
- Recent research has found a swirling flow induced by a twist-tape swirl blade inserted in the submerged entry nozzle of both slab and billet continuous casting molds to be remarkably effective for controlling the fluid-flow pattern in mold filling. The objective of the work reported on in this paper was to investigate usage of the swirl blade in the filling of molds in uphill teeming. Both mathematical and physical modeling were employed. Resulting velocity predictions and measurements corresponding to different positions in the water model were compared. Specific focus was on manipulation of the flow pattern by the swirl blade and its affect on flow unevenness, i.e. tangential and axial velocities. Good agreement was observed between the calculated and experimental results. The study's findings strongly suggest that equipping the entry nozzle of the uphill-teeming mold with a swirl blade would be a highly effective means of reducing flow unevenness during filling.
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| 2. |
- Kholmatov, Shavkat, et al.
(författare)
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Development of flow field and temperature distribution during changing divergent angle of the nozzle when using swirl flow in a square continuous casting billet mould
- 2007
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 47:1, s. 80-87
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Tidskriftsartikel (refereegranskat)abstract
- Recently, positive effects of swirl flow have been investigated, related to specific billet moulds with particular divergent angles in the immersion nozzles. (1-7)) Literature review showed that a systematic study of changes in the divergent angle in the immersion nozzle for continuous casting moulds had not been carried out. Therefore, in the present work we aim to investigate the development of flow field and temperature distribution inside the mould and on the meniscus while changing the divergent angle of the immersion nozzle. Swirl flow was used in the nozzle and the liquid entered a 3D square billet mould. Both physical and mathematical modelling was carried out to simulate nine different divergent angles between 0 and 160 degrees. The overall results of the study showed that a change in divergent angle has an effect on the flow pattern as well as the temperature distribution of the liquid steel in the mould. More specifically it was found that in the case of 100 degrees divergent angle nozzle billet we can observe a major shift of lower circulation compared to that of the 80 degrees nozzle billet. Furthermore, a noticeable increase of the temperature near the meniscus, for a square billet, and radial velocity component, for a round billet, was found when using the 100 degrees divergent angle nozzle compared to the 80 degrees divergent angle nozzle. Additionally, a uniform velocity and heat distribution was observed within a distance of 200 mm below the nozzle exit for nozzle outlets with 100 degrees divergent angles and larger.
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| 3. |
- Kholmatov, Shavkat, et al.
(författare)
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Effect of nozzle angle on flow field and temperature distribution in a billet mould when using swirl flow
- 2008
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Ingår i: STEEL RES INT. - : Wiley. - 1611-3683. ; 79:1, s. 31-39
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Tidskriftsartikel (refereegranskat)abstract
- Recently, interesting effects have been noted in studies of swirl flow, particularly regarding billet moulds when considering a specific divergent angle of the immersion nozzle. Therefore, in the present work a numerical analysis and water model study of the mould region of a continuous casting apparatus are performed with changing the outlet divergent angles of the immersion nozzle using swirling flow in the pouring tube, to control the heat and mass transfer in the continuous casting mould. To make our studies consistent with the previous research, which was done based on a square billet, this time we investigate round billets. The results show that the distance from the meniscus of the centres of both the lower and upper circulation loops decreases systematically with increasing the divergent angle. This, in turn, leads to: (i) a more active heat and mass transport near the meniscus (particularly over 100 degrees); (ii) a gradual change from a concentric circulation to a more clearly logarithmic spiral from the mould wall to the nozzle on the meniscus, which leads to more active heat and mass transfer; (iii) a decreased penetration depth of nozzle outlet flow (even at a comparatively small divergent angle such as 20 degrees) and a superheat dissipation in the melt.
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| 4. |
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| 5. |
- Kholmatov, Shakvat, et al.
(författare)
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Influence of Aspect Ratio on Fluid Flow and Heat Transfer in Mould when Using Swirl Flow during Casting
- 2008
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Ingår i: STEEL RES INT. - : Wiley. - 1611-3683. ; 79:9, s. 698-707
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Tidskriftsartikel (refereegranskat)abstract
- Mathematical modelling was used to study the effect of a changed aspect ratio of a continuous casting mould on the resulting flow field in the upper part of the mould when using a swirl flow in the nozzle. Model predictions were initially compared to physical modelling data. More specifically, the predicted axial velocities were found to differ only at the most similar to 3 mm/s from the measured data. Thus, the model was concluded to be sound. By changing the aspect ratio of a billet mould from 1 to 3 systematically, a numerical analysis of the mould region of a billet continuous caster was performed with a novel injection concept using swirling flow in the immersion nozzle in order to control the heat and mass transfer in the continuous casting mould. The predictions showed that the aspect ratio of the mould has a large influence on the flow field in the upper part of the mould. The meniscus temperature was found to increase with an increasing aspect ratio from 1 to 2, but the maximum temperature was found to decrease when the aspect ratio was increased above 2.
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| 6. |
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