Vapor/liquid visualization in fuel sprays

Abstract

In a series of demonstration experiments, we have shown that exciplex visualization systems can be used to photograph either the liquid or the vapor pattern in a hollow cone fuel spray. Thus, vapor density information can be obtained without the analysis of droplets. Furthermore, through image analysis of digitized negatives, we have obtained a quantitative presentations as false color maps and contour density plots. The exciplex visualization systems exploit the reversible equilibrium which may exist when an excited organic molecule (M*) reacts with a suitable ground state organic molecule to form an emitting exciplex (E*). The emission from M* can be made characteristic of the vapor and the emission from E* can be made characteristic of the liquid. Because the emission from E* is shifted with respect to that from M*, filters can suppress either the M* or E* emissions, and hence with laser sheet excitation, two dimensional vapor or liquid sections of the fuel spray can be photographed. © 1985 Combustion Institute.