Analysis of Cooling Effect of Laminar Water Flow for Steel Plate at High Temperature

Abstract

The cooling process of a hot steel plate in the forced cooling of the laminar water flow was experimentally and analytically discussed. The main results obtained in this paper are as follows:
1) The heat transfer coefficient α of the forced cooling of the laminar water flow can be deduced as "α=500·(θ_S-θ_W)^1/2" where θ_S and θ_W are the temperature of the cooled surface and the cooling water, rerspectively.
2) The radius R_B of the circular black zone can be described as " R_B= a√t" where t is the cooling time and a is the constant determined by the water flow rate and the vertical distance between a nozzle exit and cooled plate surface.
3) The cooling curve calculated at a given point in the steel plate using the heat transfer coefficient indicated in 1) agrees with the experimental cooling curve when the water cooling diameter R_W is assumed to be " R_W=a√t+ 10".