Numerical analysis and experiments on transferred plasma torches for finding appropriate operating conditions and electrode configuration for a wastemelting process

Thermal plasma characteristics of transferred plasma torches are numericall y and experimentally investigated under atmospheric conditions to find the effects of operating variables and electrode arrangements on them. A contro l volume method and a modified SIMPLER algorithm are used for numerical ana lysis, and the temperature distributions of argon plasma are calculated in different torch operating conditions of a typical transferred are torch. Tr ansferred plasma torches are designed and fabricated, which have six differ ent electrode arrangements, respectively, consisting of a conical rod catho de and a nozzle in the torch, and a distant anode material. The dynamic beh aviors of are voltage are measured to obtain stable are conditions, and a s imilarity criterion is determined to analyze static behaviors of are voltag e. For predicting the heat transfer rate to melted material from are column , measurements are made for the heat loss at the anode material and fractio ns of input power transferred to the anode. Furthermore, thermal plasma tem peratures are measured by the optical emission spectroscopy of an Ar I line . As a result of the present work, an appropriate electrode configuration a nd operating conditions for waste melting process are presented for the opt imization of transferred plasma torches. (C) 2001 Elsevier Science B.V. All rights reserved.