EFFECT OF TIP ON SWIRLING BLAST REVERSE CURRENTS IN A TSL LANCE

Abstract

In this paper, the effect of the tip design on the TSL operation is investigated. Using and analyzing the re-sults of over 400 million measurements of controlled melting parameters allowed to come to the conclusion about the visible and significant influence of the melting blast parameters on the peculiarities of the lance and its tip operation, which, in turn, affect the value of effective twist. Understanding the peculiarities of the twisted jet, formation of the blast torch and funnel in the melt allowed to generalize the data and iden-tify the dependencies of the lance operation using the proposed mathematical apparatus. When conduct-ing the research on the operating furnace in the real melting mode for many years of observation, the influence of the tip design features: length, diameter and throat on the process parameters of melting and the working campaign of the TSL was studied. The control of blowing parameters made it possible to assess the effective twist of the blowing mixture and its influence on the tip performance in order to ensure the specified melting modes and maximize the lance operating campaign. Studying the effect of the tip length and shape has shown that the required minimum length should be 350–400 mm. Reducing the length of the tip worsens the process parameters, reduces furnace productivity and may lead to melt ejec-tions as a result of its overblowing and foaming. Long tip leads to inconveniences during maintenance and the lance transfer to the direct flow blowing mode due to a sharp decrease in the effective twist, which nega-tively affects the productivity of the furnace and the tip campaign. Overpressure in the tip mouth, despite the theoretical advantages, did not give visible and controllable results in changing the furnace operation. The-oretical calculations on changing the tip diameter showed the questionable significance of this measure due to the increased probability of melt ingress into the lance mouth at constantly varying blowing parameters, which leads to constantly changing twist parameters.