简介:To understand and optimize the combustion processes in new types of internal
combustion engines, like gasoline direct-injection engines, non-intrusive laser-based
diagnostics methods have proven to be versatile and imp简介:To understand and optimize the combustion processes in new types of internal
combustion engines, like gasoline direct-injection engines, non-intrusive laser-based
diagnostics methods have proven to be versatile and important tools to measure
combustion characteristics. Most engine developers already rely on optical methods in
the development of new engines. To guarantee accurate and reliable results of optical
measurements it is necessary to carefully evaluate and characterize these techniques
under realistic conditions.
In this work a variety of laser-based diagnostics techniques, mostly based on the tracer-
LIF principle, have been evaluated for their applicability and limitations and have been
applied to different spray systems – reaching from single droplets, over model sprays to
fuel sprays in a firing test engine.
The tracer-laser-induced-fluorescence (LIF) method is based on doping the fuel with a
fluorescent substance whose fluorescence characteristics are used to measure various
physical properties of the spray, such as temperature, droplet size, or droplet velocity.
From these properties information about heat and mass-transfer mechanisms in the
spray can be gained. However, the characteristics of the used tracers must be known in
detail in order to guarantee useful and comparable results. Therefore, in this work
various tracers were characterized in terms of their evaporation and temperaturedependent
properties. The tracers Atto 680, Rhodamine 800 and Rhodamine B have
further been tested for their applicability to realistic fuels.详细>