Heat Transfer Coefficient and Flow Characteristics of Hot Steel Plate Cooling by Multiple Inclined Impinging Jets

Abstract

In the hot rolled plate manufacturing process, thermo-mechanical control process (TMCP) technology is widely used to improve controlled cooling technology. A new cooling system based on inclined staggered impinging jets was developed and adopted in a commercial steel mill. This study mainly focused on the surface flow field and heat transfer coefficient of the new cooling system. The flow field was numerically studied, and a method was developed to calculate the average heat transfer coefficient. And the relationship between jet velocity and average pressure in the impinging area was investigated. The study revealed that the average pressure almost increased linearly with improving the jet velocity. Meanwhile, the average heat transfer coefficient was observed to increase with average pressure in the range of 524–2989 Pa. However, heat transfer coefficient increased by only 8.4% with the plate moving speed of 0.7 m/s when the average pressure increased from 1623 to 2989 Pa. Additionally, the experimental data were useful to predict the cooling rate and microstructure of the steel product.