Numerical Analysis of the Effect of SEN Port Angle on Mold Level Fluctuation Based on Wavelet Transform

Reasonable mold level fluctuation is the key to maintaining stable mold production and ensuring the quality of the slab. In this study, a 0.6-scale water model was established, the wavelet transform was used to analyze the mold level fluctuation, and the particle image velocimetry (PIV) was used to measure the flow field of the mold. The results show that the wavelet transform provides more notable advantages for the investigation of the non-stationary signal of mold level fluctuation, which can be combined with the energy to make a more precise fluctuation characterization. The frequency of fluctuations consists of different frequency intervals, and the amplitude of each frequency interval changes with time. The fluctuation steadily reduces as the submerged entry nozzle (SEN) port angle increases. The contribution of waves with a frequency of 0.625 to 2.5 Hz to the fluctuation at the SEN and the narrow face of the mold (NF) presents a downward trend. At the 1/4 broad face of mold (1/4 WF), the contribution of 0.02 to 0.039 Hz decreases, and the contribution of 0.625 to 2.5 Hz increases. The different flow patterns in the mold are the main reasons for the frequency composition changes in the fluctuation. The fluctuation at the SEN and the NF is mainly related to the velocity in the Y direction of the upper circulating flow (UCF) and at the 1/4 WF is mainly related to the velocity in the X direction of the UCF.