With the development of continuous casting technology, there has been an increase in the stringent requirements for the cleanliness and quality of steel being produced. The flow state of molten steel in tundish is the key to: Optimizing the residence time of molten steel in the tundish; homogenizing the temperature of molten steel; and removing inclusions by floatation. Hence, from theoretical and practical aspects, it is imperative to examine and analyze the flow field of molten steel in the tundish in order to ensure the desired molten steel flow. In this study, a two-strand tundish with 650 mm × 180 mm slab casting is considered as the subject for this research. According to the similarity theory, combined with the geometrical shape and dimension of the prototype tundish, a tundish model with a geometric similarity ratio of 2:3 is established in the laboratory. Digital particle image velocimetry (PIV) is employed to measure and examine the flow fields at different casting speeds for a tundish containing different flow control devices. The flow in the tundish is typically turbulent and also consists of a vortex motion; it exhibits both random and ordered characteristics. Results reveal that the presence of baffles with 15° holes can cause an upward-directed flow in the outlet section and give rise to a large circulation. When the casting speed is doubled, the overall velocity of the flow field and turbulent intensity increase, leading to an increase in the molten steel surface velocity.

Spray cooling is a key technology in the continuous casting process and has a marked influence on the product quality. In order to obtain the heat transfer characteristics, which are closer to the actual continuous casting to serve the design, prediction and simulation, we created an experimental laboratory setup to investigate heat transfer characteristics of air mist spray cooling during the continuous casting secondary cooling process. A 200-mm thick sample of carbon steel was heated above 1000 °C, and then cooled in a water flux range of 0.84 to 3.0 L/(m²∙s). Determination of the boundary conditions involved experimental work comprising an evaluation of the thermal history and the heat flux and heat transfer coefficient (HTC) at the casting surface using inverse heat conduction numerical schemes. The results show that the heat fluxes were characterized via boiling curves that were functions of the slab surface temperatures. The heat flux was determined to be 2.9 × 10⁵ W/m² in the range of 1100 to 800 °C with a water flux of 2.1 L/(m²∙s). The critical heat flux increased with the increase of water flux. The HTC was close to a linear function of water flux. We also obtained the relation between the HTC and the water flux in the transition boiling region for surface temperatures of 850 to 950 °C.

Molecular solar thermal (MOST) energy systems can be utilized for the absorption, storage, and release of energy from the ultraviolet (UV) band of the solar spectrum. In this study, we designed a molecular solar thermal energy storage and release device based on the photoisomerization reaction of azobenzene. The device was integrated with a parabolic trough solar system, broadening the absorption range of the solar spectrum. By utilizing a coated secondary reflector, the system achieved efficient reflection of ultraviolet (UV) light in the 290–490 nm range, while solid-state azobenzene enabled the conversion of photon energy into chemical energy for storage and release. Experimental results under winter outdoor conditions demonstrated that: the secondary reflector significantly enhanced UV light concentration; the molecular solar thermal energy device exhibited remarkable thermal efficiency. Under an average solar irradiance of 302.23 W·m⁻², the device demonstrated excellent thermal performance, with the azobenzene reaching a peak temperature of 42.07 °C. The maximum heat release capacity was measured at 10.89 kJ·kg⁻¹·m⁻¹, while achieving a remarkable heat release power of 29.31 W·kg⁻¹·m⁻¹.

In this paper, the effects of different burner configurations on the characteristics of flameless combustion were evaluated by comparing the temperature field, NOx, OH and H2CO at different burner inlet velocity and angles through a combination of experimental and numerical simulations. The results show that increasing the burner inlet angle and gas velocity is imperative in achieving the flameless combustion, increasing the recirculation rate in the furnace, making the temperature distribution in the furnace uniform, and reducing the emission of NOx at the end of the furnace. During the simulation of flameless combustion, it was found that OH radicals and H2CO radicals were well correlated with the reaction exothermic zone, and the Reynolds number was positively correlated with the recirculation rate in the furnace. With the increase of Reynolds number, the entrainment rate of flue gas increases, and the combustion state is closer to flameless combustion. When recirculation rate Kv >2, combustion becomes flameless. Through the summary analysis of the data, it can be found that there is a critical Reynolds number for the burner to achieve flameless combustion, and flameless combustion occurs only when the Reynolds number is greater than 1.0×104.

This study investigates how different cooling water flow velocities affect the cooling performance of copper plates in a water-channel crystallizer. An experimental setup was developed and combined with numerical simulations to analyze the heat transfer and flow behavior of the copper plates. The convective heat transfer coefficient on the water channel wall and the hot-face temperature of the copper plates were quantitatively assessed. Experiments showed that, under a heat flux of 0.2 MW/m2 and cooling water flow rates between 5.39 to 9 L/s, the relative errors between the numerical simulation results and the experimental data regarding the average convective heat transfer coefficient are all within the range of 7.5% to 7.8%, each 1 m/s increase in average cooling water velocity raised the convective heat transfer coefficient by 3.21 kW/(m2•K). This confirms that cooling water velocity is a key factor influencing the mold’s cooling efficiency. Numerical simulations, conducted under a 1 MW/m2 heating flux boundary condition, indicated a similar trend: every 1 m/s increase in water velocity improved the convective heat transfer coefficient by 3.85 kW/(m2•K). The heat transfer coefficient is positively correlated with flow velocity, yet the magnitude of this increase becomes less significant at elevated flow rates compared to lower ones. Additionally, this study establishes a Power function relationship correlation between the Nusselt number (Nu) and the Reynolds number (Re) of the water flow within the channel. These findings offer a theoretical foundation and practical guidance for optimizing the cooling performance of copper plates in continuous casting molds.