Estimation of lack of knowledge about initial data influence on the numerical simulation results of work flow of axial turbine blade row

Aerospace propulsion engineering


Kolmakova D. A.*, Popov G. M.**, Baturin O. V.***

Samara National Research University named after Academician S.P. Korolev, 34, Moskovskoye shosse, Samara, 443086, Russia



Comparison of the turbomachinery numerical modeling results with experimental data shows that designers cannot achieve quantitative agreement while having qualitative agreement of the results. Uncertainty of modeling initial data is one of the reasons. The researcher must specify the particular channel geometric dimensions to create computational model. The actual dimension value is unknown — it is known only the range of possible values, defined by measuring instrument error or technological tolerance value

Similarly designer does not have reliable information about the workflow parameters, measured directly or indirectly with error. Also, usually the flow parameters distribution has complex nature, simplifying in the simulation.

Thus, there is only a rough idea of the tested channel actual sizes and flow parameters taken as boundary conditions for the numerical simulation carrying out. This leads to significant calculation quantitative errors.

Currently, there is little number of publications on this subject. And algorithms and software implementation taking into account initial data uncertainty are at early stage.

Therefore, research aimed at quantification of initial data uncertainty impact on turbomachines calculated performances was conducted.

Analysis of industry standards and turbomachinery workshop drawings from various companies was conducted at the preparatory stage. The most important turbomachinery geometric dimensions and bogey value of tolerances for it were identified in the analysis. Error values for the flow physical parameters were taken according to technical literature.

The quantification of geometric and physical variables uncertainty impact on turbomachinery row workflow was conducted using untwisted airfoil cascade of axial turbine nozzle assembly (NA) with uniform cross-section throughout the channel height.

Channel capacity, loss factor and NA outlet flow angle were accepted as controlled performance criteria. The NA base variant calculation results and experimental data comparison demonstrated that created model adequately described the processes occurring in the cascade, but not well predicted the losses numerical value.

The series of computational calculations were carried out for this cascade. The first group of calculations was aimed at the impact of geometric parameters uncertainty on NA parameters identifying. The second group — at identifying the studied parameters depending on the flow parameters changes that are used as boundary conditions in the simulation.

The obtained results showed that initial data uncertainty in CFD calculations has a significant impact on the obtained quantitative estimates. The difference between calculated data modified in accordance with the technological tolerances and accuracy of the measured values of the geometry and process parameters may exceed 5% by value of the considered criteria.


turbine, the initial data, characteristic, airfoil, throughput, loss ratio, boundary conditions, finite element mesh, computational model, tolerances, errors


  1. Lee H. B., Bauer R. C. Predictive Computational Fluid Dynamics Development and its Verification and Validation: An Overview, Proceedings of the ASME Fluids Engineering Division Summer Conference, 2009, Vol. 1, Issue PART C, pp. 2001-2010.
  2. Albert S., Epple P., Delgado A. Analysis of Propeller Design Methods and Validation With the CFD Computation of a Propeller-Pump, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 2012, Vol. 7, Issue PARTS A, B, C, D, pp. 275-282.
  3. Ayoubi C., Hassan O., Ghaly W. and Hassan I. Aero-thermal optimization and experimental verification for the discrete film cooling of a turbine airfoil, Proceedings of the ASME Turbo Expo, 2013, Vol. 3, 2013 ASME Paper No. GT2013-95325.
  4. Barth T. A Brief Overview of Uncertainty Quantification and Error Estimation in Numerical Simulation, NASA Ames Research Center, NASA Report, 2011.
  5. Nikushchenko D.V. Issledovanie techenii vyazkoi neszhimaemoi zhidkosti na osnove raschetnogo kompleksa FLUENT (Investigation of viscous incompressible fluid flow based on the calculation complex FLUENT), Sankt-Peterburg, sankt-peterburgskii gosudarstvennyi morskoi tekhnicheskii universitet, 2004, 94 p.
  6. Roache P.J. Quantification of uncertainty in computational fluid dynamics, Annual Review of Fluid Mechanics, 1997, vol. 29, pp. 123-160.
  7. Dinescu C., Smirnov S., Hirsch C., Lacor C. Assessment of intrusive and non-intrusive non-deterministic CFD methodologies based on polynomial chaos expansions, Int. J. of Engineering Systems Modelling and Simulation, 2010, Vol. 2(1/2), pp. 87-98.
  8. Montomoli F., Massini M., Salvadori S. Geometrical uncertainty in turbomachinery: Tip gap and fillet radius, Computers and Fluids, 2011, Vol. 46(1), pp. 362-368.
  9. Wang X. CFD Simulation of Complex Flows in Turbomachinery and Robust Optimization of Blade Design, Ph.D. thesis, available at:, 2010.
  10. Lopatki kompressorov i turbin. Predel’nye otkloneniya razmerov, formy i raspolozheniya pera, OST 1 02571-86 (Compressor and turbine blades. Maximum deviations in size, shape and location of the airfoil, Industrial Standard 1 02571-86), Moscow, Standarty, 1987, 36 p.
  11. Baturin O.V. Sovershenstvovanie protochnoi chasti osevykh aviatsionnykh turbin pri ikh gazodinamicheskoi dovodke s pomoshch’yu chislennykh metodov gazovoi dinamiki (Improving of the aircraft axial turbine blading during their gas-dynamic development with the help of gas dynamics numerical methods) Doctors thesis, Samara, SSAU, 2005, 24p.
  12. Venediktov V.D. Atlas eksperimental’nykh kharakteristik ploskikh reshetok okhlazhdaemykh gazovykh turbin (The atlas of experimental performances of cooled gas turbine blade plane), Moscow, TsIAM, 1990, 393 p.
  13. NUMECA, User Manual AutoGrid5 Release 8.4,, Belgium, January 2008.
  14. Belousov A.N., Musatkin N.F., Rad’ko V.M. Teoriya i raschet aviatsionnykh lopatochnykh mashin (Theory and calculation of aviation turbomachines), Samara, Samara State Aerospace University, 2003, 344 p.

Download — informational site MAI

Copyright © 2000-2021 by MAI