<p>Driven by the “dual-carbon” policy, arc steam plasmas provide high-temperature, low-cost, and environmentally friendly heat sources for a variety of applications. However, severe anode erosion caused by steam condensation has limited the large-scale application of arc steam plasma torches. Suppressing condensation depends on reducing heat loss from steam in the anode cold boundary layer, a process that is influenced by plasma flow field characteristics, yet the effects of these characteristics have not been systematically reported. This study investigates two representative flow fields: one generated by a trumpet-shaped anode, which forms stratified flow between the cold boundary layer and the plasma, and the other produced by a stepped anode, which enhances boundary layer turbulence. Through systematic experiments and numerical simulations, the study comparatively analyzes their electro-thermal characteristics, anode exit temperatures, anode erosion behavior, and physical properties inside the torch. The results show that plasma flow field characteristics have a significant impact on anode erosion: stratified flow fields lead to severe erosion, while turbulence-enhanced flow fields can significantly suppress it. Moreover, only under turbulence-enhanced flow fields is the electron temperature at the torch exit higher and sensitive to changes in current. These findings highlight the importance of turbulence-enhanced flow fields for extending the operational lifetime of steam plasma torches.</p>