Combustion Mechanism of Gas Porous Burner Installed an In-Line Tube-Bank Heat Exchanger

The in-line tube banks heat exchanger installed on a gas porous burner using air as the working fluid and LPG as fuel is designed and experimented. Effectiveness of the heat exchanger (ε) and temperature profile of porous burner (T) are investigated. Therefore, the test rig is divided into 4 sections. The first section is premixed-gas supplying section (Air and LPG). Then, premixed-gas is preheated in the second section where this region is porous burner (PB). The ignition zone is the third section. The final section is the in-line tube-banks heat exchanger (HE). Alumina-Cordierite ball (Al-Co) having average diameter (d) of 19 mm and porosity (φ) of 0.395 is adopted as porous media. From heat exchanger design, stainless tube with outer diameter of 19 mm and thickness of 1 mm is developed as a 24 tube of an in-line tube-banks heat exchanger and is attached below the PB and the ignition zone. From experiment, it is found that T is increased as increasing the equivalent ratio (Φ) and the volumetric premixed-gas velocity (Vmix). However, the trend of T is slightly decreased as increasing the water flow rate fed into heat exchanger (QAH). In the result of ε, it is found that ε is increased as increasing Φ and Vmix. On the other hand, the trend of ε is decreased with QAH increasing. Thus, the maximum of ε is obtained at Φ = 0.75, Vmix = 30 m3/hr and QAH = 42 m3/hr which there is 58.7%.