Hochgeschwindigkeits 3D PIV System
Final Report Abstract
KIAI - Knowledge for Ignition, Acoustics and Instabilities: Providing reliable Low NOx Methodologies for combustors (EU FP7, 234009). Scientific objectives: Predict the coupling between acoustics and the flame Determine the acoustic boundary conditions of multi-perforated plates surrounding the combustion chamber Account for non-premixed spray flows in the combustion process Explore aerodynamic unsteadiness in strutted pre-diffusers adapted to high mass flow injections Develop a liquid film break-up model for an injector (Institut für Thermische Strömungsmaschinen) Evaluate the sensitivity of LES predictors to small technological variations of geometry KIAI is a European funded research programme involving 18 partner organisations from major European engine manufactures, universities, research institutes and companies from the combustion area. KIAI was launched in May 2009 for duration of 4 years under the leadership of Snecma. www.kiai-project.eu Within the KIAI project, the Institut für Thermische Strömungsmaschinen used the high speed PIV system to develop a better understanding of the atomization process in advanced prefilming air blast atomizers. The PIV system was adapted to investigate the liquid film breakup at elevated pressure conditions. Based on the high speed observations new insights in this complex physical process could be obtained that lead to the development for correlations to predict this key process in modern fuel preparation systems for future aero engines. TECC-AE - Technologies Enhancement for Clean Combustion in Aero-Engines (EU FP7, 211843) Scientific objectives: To solve the main limitations identified during past and ongoing projects appearing when lean combustion is pushed toward its maximum potential about NOx emissions reduction. In particular, TECC-AE will Provide full combustor operability in terms of ignition, altitude relight and weak extinction performance. Suppress the occurrence of thermo-acoustic instabilities by reducing the combustor sensitivity to unsteady features to a level such instabilities will not happen. To ensure injection system robustness with respect to coking that can appear during transient operations of the engine. To develop, demonstrate and validate design rules, CFD capabilities and scaling laws To provide knowledge for global optimisation of the multiplicity of combustion parameters of lean combustion systems to achieve lower flame temperatures and thus lower thermal NOx formation (e.g. homogeneous fuel-air mixtures, cooling (Institut für Thermische Strömungsmaschinen) and unsteady behaviour optimisation). TECC-AE has been launched in July 2008 for duration of four years and is co-ordinated by Snecma and gathers 18 partners from different European countries. www.tecc-project.eu Within the TECC-AE project, the Institut für Thermische Strömungsmaschinen used the high speed PIV system to investigate the complex 3D flow field of aero engine injectors. The strong interaction of the main flow structures with the cooling flow have a huge impact on the performance and reliability of the cooling scheme applied to the combustion chamber. Due to the high speed investigations a better understanding of this complex process could be gained. SFB CRC 606 TPC9 Mechanisms of Self-induced Oscillations in Spray Combustion: Comparison of thermo acoustic oscillations of gaseous (premixed and non-premixed) and spray flames Identification of low frequency combustion instabilities Flame propagation Feedback of atomization with thermo acoustic oscillations Airblast atomization with unsteady air flow Identification of the instability mechanism SFB CRC 606 TPC9 is part of a three-part SFB, 2002-2012, sub project C9 is one sub project within the third funding period and represents one of the 31 sub project. It is dedicated to the better understanding of unsteady combustion processes in both microscopic scales as well as in 1:1 scaled combustion chambers of jet engines and internal combustion chambers. Within the SFB CRC 606 TPC9 time resolved flow field measurements could be performed by the Institut für Thermische Strömungsmaschinen, using the high speed PIV system. The advanced high speed PIV system enabled the investigation of the two most important flow instabilities, the processing vortex core as well as a yet unknown flow instability for spray combustion. The excitation mechanisms of these instabilities could be identified. Based on these observations design rules for new combustion chambers can be deduced.
