Effect of water flow rate on the heat transfer coefficient of a hot steel plate during laminar flow cooling

Establishing an accuracy relationship between the convective heat transfer coefficient and cooling process is the key to improve the laminar cooling control model. The convective heat transfer coefficient and corresponding surface temperature were calculated by the finite difference method and the inverse heat conduction method. The effects of cooling water jet flow rate on the heat transfer coefficient and surface temperature was investigated when the cooling water jet flow rate varied from 0.9 to 2.1 m³·h^-1. It is found that the convective heat transfer coefficient is a nonlinear function of the surface temperature during laminar flow cooling. Within a distance of 70 mm from the stagnation line, the cooling flow rate has no effect on the heat transfer coefficient and surface temperature. But outside 70 mm, the heat transfer coefficient ratio becomes smaller with increasing distance from the stagnation line. It is also shown that relatively good agreement is obtained between the calculated and measured curves.