Abstract
In the present study, steady numerical simulations performed on the counter rotating turbo fan (CRTF) COBRA are compared with experimental data carried at the CIAM C-3A test-bench in Moscow. For this purpose, a systematic analysis of the measurement uncertainties was performed for the global aerodynamic performances of the CRTF, namely, the massflow, the total pressure ratio, the isentropic efficiency, as well as the torque ratio applied on both fan rows. Several numerical models are investigated to highlight their effects on the aforementioned predicted quantities. Differences in modeling consist in grid resolutions and the use of two turbulence models popular in the turbomachinery community. To match as much as possible the experiment running conditions, the performance map of the CRTF is simulated using the exact measured speed ratio and massflow. The comparisons show good estimations of the numerical simulation over the entire performance map. The main differences between the turbulence models occur at part-speed close to stall conditions. More surprisingly at aerodynamic design point, the importance of the turbulence modeling on the predicted torque ratio has been pointed out.
Highlights
The annual number of airplane passengers was expected to practically double in the coming 20 years
The 100% running condition is represented in cyan, with the iso-speed line which is symbolized with unfilled-diamondshape symbols and the iso-torque line with unfilled squares
The medium fidelity simulations associated with each iso-line are plotted by respecting the color system in place, with the k − turbulence model represented by triangles and the Stress Transport (SST) one by circles
Summary
The annual number of airplane passengers was expected to practically double in the coming 20 years. One year on from the pandemic began, a more pessimistic scenario, that seems to be emerging, forecasts a number of passengers per year is not expected to return to its pre-COVID-19 level before 2024 [4]. By 2050, it is expected that the future airplanes will reduce the previous cited emissions to, respectively, 75% and 90%, in comparison to year-2000 aircrafts. To cope with these objectives, the counter rotating turbo fan appears as a solution that has potential in comparison to a single rotating fan, where the stator is replaced by a fan which is rotating in the opposite direction of the front fan [7,8,9,10]. It could result in a 1.8% efficiency improvement than a single fan architecture, for the same level of compression [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
