FP7 FACTOR project

The main objective of the FACTOR project is to optimize the combustor-HP turbine interaction design. This will be achieved through a better understanding of the interaction between the coolant system, the transport (secondary flows) and mixing mechanisms enabling an SFC reduction of about 2.0%. Indeed, the optimization of the coolant mass-flows will allow more of the core-flows to pass through the combustor. The simplification of combustor design and the different possible HP Turbine architecture will enable a lower weight (1.5%) and cost (3.0%) solution to be found.
New Turbine Test Facility


At the turbine department of the Institute of Propulsion Technology at DLR in Göttingen a turbine test facility is currently in operation, which was originally designed and build up in 1971 for the investigation of the flow around rotating annular cascades, the so called Wind Tunnel for Rotating Cascades (RGG). Due to its unique features this facility was up to now well occupied by turbine stage investigations for industrial, national and international research projects.

Because of the rapid turbine development in recent years, the RGG will not cover all requirements from turbo machine industry and topics for future research projects. Measurements with modern single-stage high pressure turbines have shown, that important key and off-design operating points were close to the limitations of this test facility, some points could be set up only with compromises. As a result there is a need for a new test rig that is both capable of simulating the main flow parameters of future high-performance turbines (e.g. higher pressure ratios, extension to low pressure turbines, more stages etc.) and enough size to enable more detailed measurements during the experiments.

The Institute of Propulsion Technology will design and build up the new turbine test facility at DLR in Göttingen. This facility will be build up in two stages of extension and starting its operation in 2013. The new rig, called Next Generation Turbine Test Facility (NG-Turb), will operate as a closed circuit with dry air as flow medium, allowing the independent setting of Mach- and Reynolds numbers. Reynolds numbers can be adjusted by varying the overall pressure or temperature level in the circuit. The flow medium is driven by a four stage radial gear compressor with a high pressure ratio and a broad performance map for small to very high volume flow, designed and manufactured by MAN Diesel & Turbo SE in Oberhausen.

Oxford Turbine Research Facility (OTRF)
The Oxford Turbine Research Facility (OTRF) is a short duration wind tunnel, capable of testing an engine size turbine at the correct non-dimensional parameters for fluid mechanics and heat transfer (M, Re, Tu, Tg/Twall). The facility has been used to test a single HP turbine stage and a 1.5 turbine stage turbine with the presence of inlet temperature distortion and inlet swirl.
A novel feature of the facility is the aerodynamic turbo-brake, which is on the same shaft as the turbine and is driven by the turbine exit-flow. At the design speed the turbobrake power is matched with the turbine, and thus constant speed is maintained during a run. Typically, steady conditions are achieved for 500 ms.

Hot streaks, rotatable with respect to the NGV leading edge, are generated by blowing cool air through struts upstream of the HP NGVs. Studies have included the impact of clocking the hot-streak with respect to the HP vane. The mean temperature is the same for both uniform and non-uniform inlet temperature: 444 K. The peak-to-mean and minimum-to-mean temperature ratios are approximately 1.65 and 1.19.
The OTRF also has the capability of introducing swirling inlet flow similar in level to that produced in lean-burn combustion. A whirl angle variation of +/-45 degree was achieved during the TATEF II EU programme.
Film cooling studies have been conducted in previous EU programmes on both the vane and the rotor surfaces. Effusion cooling experiments on the rotor liner segment have been conducted for an industrial gas turbine application.



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