Low pressure combustion chamber

This system is constructed for experiments with methane air flames which are stabilized on a McKenna burner at a (vacuum) pressure of 60 hPa. The flame was subjected to DC as well as pulsed electric fields directed towards the burner surface.

Axial profiles of the temperature of CH were measured by emission spectroscopy. Electric fields can modify the flow pattern and thus extend the stability limits of flames. Another aspect that has received much attention is the field induced reduction of emissions such as CO and NOx.

The central porous bronze plug was 60 mm in diameter and was surrounded by a hollow-cylindrical ring of the same material which was connected to a separate gas supply. Water cooling was provided by a coil of copper tubing embedded in the burner plug. The burner was mounted inside the lower vertical arm of a Ultra High Vacuum 6-way Cross. A vacuum pump was connected to the upper vertical arm of the six-way cross. A regulated throttle valve kept the chamber pressure at 60 ± 1 hPa. One of the horizontal arms of the six-way cross served to accommodate a ceramic high-voltage isolator which supported a ring electrode to keep the distance to the burner around 60 mm. Optical access with fused-silica windows was possible through the remaining three arms of the 6-way cross.