Теплообмінні процеси при валковій розливці-прокатці металів

• Datum: 2023
• Hauptverfasser: Нурадінов, Абді, Ноговіцин, Олексій, Нурадінов, Ібрагім, Баранов, Іван, Сіренко, Катерина
• Format: Artikel
• Sprache: Ukrainisch
• Veröffentlicht: Physico-technological Institute of Metals and Alloys 2023
• Schlagworte: валковий кристалізатор; теплообмін; швидкість теплоносія; площа тепловідведення; шорсткість; коефіцієнт тепловіддачі; кількість тепла
• Online Zugang: https://www.metalsandcasting.com/index.php/mcu/article/view/16
• Назва журналу: Metal and Casting of Ukraine

Physical modeling has been used to study the processes of heat exchange between the melt and the roll crystallizer with roll casting-rolling of metals. Based on the theoretical analysis of heat exchange processes between the bandage of the roll crystallizer and the cooling water, the possible levers of their intensification are determined: the speed of the coolant, the area and relief of the heat sink surface. Regularities of change of parameters of heat exchange between the hardening metal and the water cooling the crystallizer, depending on ways of influence on it are established. It is shown that a significant increase in the rate of heat dissipation is observed in the case of increasing the speed of water movement to a certain level (up to 2.5 m/s). And with increasing the area of heat dissipation, the degree of intensification of heat transfer processes in the mold does not depend on the speed of water movement. Increasing the intensity of heat transfer processes in the mold at the artificial roughness of the heat transfer surface is that when the flow of liquid on the ledge behind it a vortex is formed, which destroys the structure of the viscous sublayer, turbulizing it. As a result, at a constant velocity of the fluid, the viscous laminar sublayer is completely destroyed or decreases in thickness, which increases the heat transfer coefficient without increasing hydraulic losses. Therefore, it is established that the most optimal of the considered tool options in terms of accelerating heat transfer processes is the method of inducing artificial roughness on the bandages of the rolls. It is shown that along with the intensification of heat dissipation, this method, due to the turbulence of the viscous laminar sublayer of water, significantly reduces the formation of scale on the heat exchange surface. And this, in turn, increases the periods of preventive maintenance of the molds. Based on the obtained results, practical recommendations for improving the efficiency of thermal work of the roll crystallizer in roll casting-rolling of metals are proposed.