T1.2,T1.3 (KIT/ITS)
A cost-effective URANS setup was conceived based on the use LES data. This model was used to carry out a detailed parametric study on the combustor aerodynamics.
LES reactive numerical approach was then setup and validated on a literature test case (see Figure 1). The approach was then used to investigate the CHAIRLIFT concept to optimize the contouring of the side wall (see Figure 2).
As an additional outcome of the task, a preliminary design of possible cooling concept for the sidewall was carried out (Figure 3)
T2.1 T2.2 (UNIFI)
The main goal was to define a representative numerical setup for LES investigations. Results related to the validation of the computed flowfield in isothermal conditions are reported in Figure 4.
LES turbulent combustion models were considered to validate basic low-swirl lifted flame prediction. Investigated models belong to FGM family (with heat loss and flame stretch effects ) and ATF. A hybrid ATF-FGM model was also tested. Figure 5 reports a comparison of some of the tested models against measured CO and temperature. LES results permitted to deeply investigate the flame stabilization process (Figure 6).
CFD investigations of the KIT multi-burner rig have been carried out in T2.2. Figure 7 reports a comparison with exp data. The developed CFD model was then used to investigate several inclination angles defining a performance parameter to assess flame stabilization capabilities (Figure 8).
T 2.3 (URN)
The goal was to provide the spray distribution to the reactive simulation. A workflow based on segregated multiple steps was developed (see Figure 9). A validation of the proposed model was carried out on a literature test case and then applied to the current prefilmer airblast.
T3.1 (KIT/EBI)
A series of experimental tests were conducted at a multi-burner array test rig consisting of up to five modular burners at different inclination angles, equivalence ratios, air pressure drop across the nozzle, and varied air inlet temperature at ambient pressure. Figure 10 reports the stability of studied solutions as a function of pressure drop. Figure 11 is summarizing NOx emissions for two cases varying inlet air temperature.
T3.2 T3.3 (KIT, UNILE)
To study the effect of plasma discharge on the flame stability for the lifted flames, experiments on a single burner were performed. A large test campaign was carried out mostly focusing on flame stability and emissions (Figure 12). Additional tests were carried out by installing an ion sensor probe developed by KIT to carry out an high frequency monitoring of the flame (Figure 13).
T4.1 (UNIFI, KIT)
A hybrid approach combining Chemical Reactor Network and best fitting of the exp data, was used to upscale measured NOx emission up to max take-off conditions for reference engine cycles. Figure 14 reports the obtained scaled NOx emission for cycles at 13bar and 33bar. For the target air fuel ratio (26) predicted emissions are below 2 g/kg.
T4.3 (UNIFI)
LES investigation of the LBO transient of the multi-burner rig was carried out for the inline case, confirming the key role of outer recirculation in flame stabilization. A series of temperature snapshots during flame blow-off is reported in Figure 15.
The overall value and impact of the obtained results are confirmed by the significant number of scientific papers produced (6 journal articles and 12 conference papers and 2 PhD thesis) as well as by the exploitation actions set up, with a patent pending and with the developed methods and rigs considered for new researches.
