Three-dimensional flow and heat transfer in thermal plasma systems

Three-dimensional (3-D) modeling of thermal plasma systems is still a challenging problem. Modeling results recently obtained in our group are briefly presented in this paper concerning the 3-D flow and heat transfer characteristics of the thermal plasma reactor, plasma jet and non-transferred arc plasma torch. A well-validated non-commercial computer code is employed in the study. It is shown that when particulate-matter and its carrier-gas are injected into a plasma reactor through a single port at the side-wall of reactor, appreciable 3-D flow and heat transfer effects will appear and cannot be well modeled by any two-dimensional models. The 3-D effects influence the particle motion and heating within the reactor. For a plasma jet with lateral injection of carrier-gas and particles, the 3-D effects are also shown to be non-negligible. Marked 3-D special features of the flow and heat transfer within DC non-transferred arc plasma torches have been demonstrated even for the torch with completely axi-symmetrical geometrical configuration, working gas admission and electrical current connection. The predicted results are well consistent with experimental observation. Further research requirement is also discussed in this paper.