Construction and Axial Temperature Measurements of a Compact Diesel-Fired Laboratory Combustion Chamber

Abstract

Diesel in burners and compression-ignition engines burns as a spray diffusion flame. Undergraduate laboratories seldom have a confined diesel flame that can be started and instrumented in class. The objective of this work was to build a compact diesel-fired chamber for teaching and to record axial temperatures under three visually set firing modes. A commercial BT14GW gun burner was mounted on a firebrick-lined steel cylinder 1.0 m long and 0.25 m in internal diameter. The flame was observed through a window in the chamber wall. Three K-type thermocouples were fitted at 0, 0.5 and 1.0 m from the burner. The fuel setting was left unchanged. Combustion air was varied with the air damper, giving a long yellow-orange flame (rich), a compact blue-white flame (near stoichiometric) and a short pale-blue flame (lean). Air and fuel mass flows were not measured, so the temperature profile was higher for the visually classified rich condition than for the visually classified lean condition. Once the chamber temperatures had settled, the mean indicated values nearest the burner were 960 °C (rich), 920 °C (near stoichiometric) and 840 °C (lean). At the chimney, they were 640 °C, 600 °C and 520 °C. The fall over 1.0 m was 320 °C in each case. Radiation error was not corrected, so the figures are indicated temperatures. The chamber can be moved in a teaching laboratory; it is not offered as a fully instrumented research furnace.