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Time and Spatially Resolved Temperature Measurements of a Combusting Diesel Spray Impinging on a Wall
Abstract:
The interaction between a combusting diesel spray and a wall was studied by measuring the spray flame temperature time and spatially resolved. The influence of injection sequences, injection pressure and gas conditions on the heat transfer between the combusting spray and the wall was investigated by measuring the flame temperature during the complete injection event.
The flame temperature was measured by an emission based optical method and determined by comparing the relative emission intensities from the soot in the flame at two wavelength intervals. The measurements were done by employing a monochromatic and non intensified high speed camera, an array of mirrors, interference filters and a beam splitter. The studies were carried out in the Chalmers High Pressure High Temperature (HP/HT) spray rig at conditions similar to those prevailing in a direct injected diesel engine prior to the injection of fuel. Fuel was injected into the combustion chamber by a common rail system using an injector with a single hole nozzle. The combusting spray impinged on a wall whose temperature was similar to the combustion chamber gas temperature.
Results of these experiments show variations in the flame temperature as a consequence of the interaction between the combusting spray and the wall. There is a reduction in the flame temperature after impingement followed by a temperature rise as the wall is heated up by the flame. The effects caused by injection pressure, injection sequences and gas temperature lead to differences in the heat flux between the combusting spray and the wall.