Characterization of Oxygenated-Fuel Combustion by Quantitative
Multiscalar SRS/LIF Measurements in a Diesel-Like Jet 2018-01-5037
Due to experimental challenges, combustion of diesel-like jets has rarely been
characterized by laser-based quantitative multiscalar
measurements. In this work, recently developed laser diagnostics for combustion
temperature and the concentrations of CO, O2, and NO are applied to a
diesel-like jet, using a highly oxygenated fuel. The diagnostic is based on
spontaneous Raman scattering (SRS) and laser-induced fluorescence (LIF) methods.
Line imaging yields multiscalar profiles across the jet cross section.
Measurements turn out to be particularly accurate, because near-stoichiometric
combustion occurs in the central region of the jet. Thereby, experimental
cross-influences by light attenuation and interfering emissions are greatly
reduced compared to the combustion of conventional, sooting diesel fuel jets.
This is achieved by fuel oxygenation and enhanced premixing. The second stage of
ignition occurs relatively close to the end of fuel injection, so that the flame
is similar to partially premixed, low-load, single-injection, low-temperature
combustion (LTC) in heavy-duty engines. Since exhaust-gas recirculation (EGR) is
not applied in this work, relatively high NO concentrations (~500 ppm) are found
in the downstream jet. The origin of enhanced NO formation is investigated in
more detail by the other measured scalars. The local equivalence ratio is
estimated based on both the O2 and CO profiles. Temperature
measurements yield further information for the interpretation of NO signals.
Rapid leaning caused by the end of injection is indicated by the CO and
O2 data, but the corresponding effect on temperature and NO
appears to be weak.
Citation: Schulz, C., Ottenwälder, T., Raffius, T., Grünefeld, G. et al., "Characterization of Oxygenated-Fuel Combustion by Quantitative Multiscalar SRS/LIF Measurements in a Diesel-Like Jet," SAE Technical Paper 2018-01-5037, 2018, https://doi.org/10.4271/2018-01-5037. Download Citation
Christian Schulz, Tamara Ottenwälder, Thomas Raffius, Gerd Grünefeld, Hans-Jürgen Koß, Stefan Pischinger