Improvement of the Steel-Plate Temperature During Preheating by Using Guide Vanes to Focus the Flame at the Outlet of a Gas Torch

Abstract

The temperature distribution on a steel plate during a preheating process was comparedusing gas torch models with and without guide vanes. Numerical simulations were done usingANSYS FLUENT software, and experiments were done using thermal images obtained by aTVS-200EX infrared thermal camera. Liquefied petroleum gas (LPG) was used as fuel for the gastorch in the simulation and experiment. The temperature distribution on the steel plate and theflame region were first compared. The temperature increase caused by the flame concentrationwith the guide vanes was 65 C. The transient and steady-state temperature distribution on theback side of the steel plate were then examined. The results showed good agreement between thesimulation and experimental results. At steady state, the back-side temperature deviation of thesteel plate between the numerical simulation and experimental results was approximately 4.9%.The effects of the equivalence ratio (Φ), Reynolds number (Re), and the downstream distance ratioof the combustion gas from the torch outlet to the steel plate (H/d) on the temperature distributionwere also investigated. The highest temperature distribution was found in stoichiometriccombustion. The temperature of the plate increased as the Reynolds number increased from 2368 to4876 but decreased as the distance ratio (H/d) increased from 25 to 75. The guide vane angles at thegas torch outlet were from 30 to 60 degrees, and the angle of 40 degrees resulted in the highesttemperature of the steel plate.

Keywords

• Gas torch with guide vanes
• impinging flame jet
• steel preheating
• temperature distribution
• LPG/air mixture