As in many thermal processing technologies, there is a delicate balance between productivity and quality during ingot cooling process. Higher cooling velocities increase productivity but also create higher temperature gradients inside the ingot. Such a fast cooling does not leave sufficient time to establish the equilibrium within the solid, thus the final metal structure is strongly affected by the set up cooling mode throughout the liquid metal solidification. The first intention in this paper is to compare between three cooling modes in order to identify the required mode for a continuous casting process. Then, we study the influence of heat transfer coefficient on metal liquid-to-solid transition through the spray-cooled zone temperature and the metal latent heat of solidification. A gray iron continuous casting process subjected to water-sprays cooling was simulated using the commercial software for modeling and simulating multiphysics and engineering problems. The primary conclusions, from the obtained results, show the forcefulness of water spray cooling regarding standard cooling. Afterward, we highlight the great influence of heat transfer coefficient on the location of transition region as well as the relationship between heat transfer coefficient, wall outer temperature, latent heat dissipation, and the solidification time.

The article shows the effect of the supply pressure of fog nozzles on the process of ammonia sorption. In the tests, the nozzles flow characteristics Q=f(p) and the dependence of NH3 concentration as a function of the water stream feeding in time at different supply pressures were determined. For the TF 6 NN, TF 6 V, NF 15, CW 50 nozzles, measurements were carried out at the following supply pressures: 0.1 MPa; 0.2MPa; 0.3MPa; 0.4MPa; 0.5MPa. It was observed that the greatest effect of nozzle feed pressure on ammonia sorption efficiency may be expected at lower pressure values. At higher values, the sorption rate becomes stabilized and even starts to decrease. The decreases in the sorption rate constant observed for higher pressures may be due to a reduction contact time of the droplet and the achievement of the critical mixing rate of ammonia vapors in the air intensively saturated with water streams. This is due to diffusion rate limitations. The measurements show that the use of supply pressures for fog nozzles above 0.4 MPa is not justified. It should be noted that varying the feed pressure of nozzles of various designs can affect their ammonia sorption efficiency differently. The type of nozzle and supply pressure affects the distribution of droplets in space. The angle of dispersion and the shape of the generated jet have a critical influence on the efficiency of the sorption process. Complete filling of the space and a large spray angle assure relatively high sorption efficiency.