The Simulation Of High-pressure Water Jet And Development Of Design Platform For Descaling System

High-pressure water descaling system is one of the main equipments applied in the hot rolling production line of the steel industry. Currently, traditional manual calculation, which has the shortcomings of time consuming, difficult to ensure accuracy, and not conducive to optimal choice among multiple programs, is usually used for the design of descaling system. Therefore, this paper mainly conducts research on the high-pressure water descaling system, based on programming software Visual Basic6.0. The work designs and develops design platform of descaling system, convenient to the selection and calculation of each parameter, which improves the design of descaling system. In addition, simulation analysis of high-pressure water jet flow field and temperature field with the help of computational fluid dynamics (CFD) software Fluent is conducted. Jet movement influencing factors and billet surface temperature drop rule are obtained, which is important for the rational design of descaling system. Contents include the following aspects:(1) Establishes a computational model of descaling system by combining high-pressure water jet theory and hydrodynamics knowledge. Practical computing model of various parts of the system, including parameter calculation of water jet, parameter calculation of nozzle mounting, calculation of resistance loss, parameter calculation of high-pressure pumping station, and parameter calculation of pipe is obtained.(2) Introduces the application of design platform of the descaling system by hot rolling examples, including computing function of the descaling system, output and storage of calculation result. Different system parameters are analyzed and compared, and their effects for descaling are obtained.(3) The simulation and analysis for outside flow field of the nozzle using multiphase flow VOF model is conducted, under spray distance of 200mm,300mm,500mm and 1000mm. According to the simulation results, the best spray distance of high-pressure water descaling is about 200mm. It should be noted that if the spray distance is too short, it will appear strong water back flow, resulting in mutual interference between flow bundles and reduction of the descaling blow force. Therefore, in the case that meets the minimum impact descaling blow force, the spray distance should be adjusted to the maximum condition.(4) For the shock of high-pressure water to hot billet surface, a temperature field model for billet surface is established. Simulation using flow rate of 145 l/min A-type nozzle and flow rate of 861 l/min B-type nozzles is conducted. Results are obtained from the above analysis:when using the A-type nozzle, the temperature change of billet surface is large and the temperature drop depth is also large; however, when using the B-type nozzles, corresponding temperature change is small. Therefore, a smaller flow rate of the nozzle for descaling should be chosen. Grasp the variation of the billet surface temperature can provide a theoretical reference for desired open rolling temperature after descaling.