Extension Of The Multall Open Source Throughflow Code For The Improved Endwall Loss Simulation

Date

2023-01-01

Author

Bilgiç, Mustafa
Baran, Özgür Uğraş
Aksel, Mehmet Haluk

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Accurate loss modeling is critical for throughflow calculations to capture correct streamtube geometry and the accurate spanwise distribution of flow properties during quasi three-dimensional design of a turbomachinery blade. In this study, the modification of Cf (friction factor)-based loss computation in MULTALL throughflow code and its difference from classical empirical loss-based throughflow solvers are studied. The original form of the MULTALL applies a constant friction factor on all wetted surfaces to account for the losses in the throughflow analysis. However, in a typical turbomachinery blade passage regardless of being compressor or turbine passage, the entropy generation near the endwall regions cannot be handled by imposing constant Cf on the wetted surface due to the complex endwall flow structure. To improve the loss prediction capability of MULTALL, the friction factor near the endwall regions is modified. Therefore, all these complex flow structures can be resolved. In other words, the Cf distributions are recalculated near the endwall regions such that the secondary and tip clearance losses can be represented accurately. Furthermore, an empirical-based loss prediction capability is also brought to the MULTALL via distributed loss model approach. The entropy gradient required for the calculating of friction force on blade surfaces is calculated from empirical loss models. Then, the calculated friction force is included in the solution via the source term. Both methods are validated with the experimental results of a single stage transonic compressor. The modified Cf model shows better agreement with the experimental data near endwalls as compared to results of empirical based model and the original form of MULTALL solver.

Subject Keywords

Compressor, Endwall Losses, Loss, MULTALL, S1 Surface, S2 Surface, Throughflow

URI

https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85177220984&origin=inward
https://hdl.handle.net/11511/106984

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Department of Mechanical Engineering, Conference / Seminar