<p>Due to the growing significance of the top submerged lance (TSL) technology in metal production and recycling industries, numerous studies have been performed on TSL flows. Most of the studies focused on flow characteristics of laboratory-scale TSL under an isothermal condition. However, the effects of temperature variation and fuel combustion are rarely explored. This study develops a 3D numerical model, which incorporates specialized sub-models (i.e., isothermal model, non-isothermal model, and combustion model), to investigate the bath dynamics of a pilot-scale TSL furnace. The flow data, bubble frequency, slag splashing, and gas–slag contact area have been analyzed to reveal the flow characteristics, and to capture the differences under different conditions. The comparative studies show that flow characteristics such as flow velocity, flow fluctuation, bubble frequency, and slag splashing are slightly varied when only considering temperature variations, but are largely changed when considering combustion. In addition, the gas–slag contact area increases markedly compared to that from the isothermal model. Distinct differences of bath dynamics under realistic conditions highlight the necessity of integrating specialized sub-models to resolve industrial TSL flows. This work can provide in-depth insights into the real TSL flow dynamics.</p>