Numerical Simulation of Performance of an Axial Turbine First Stage

Abstract: T is work s pr s nt d t rst st g p rfor n t d sign nd off d sign op r ting points of n xi tur in , wit two st g s using nu ri si u tion xp ri nt t ods of pr di ting t p rfor n of xi tur in is ost nd ti onsu ing o p r d to t o put tion uid d n i s ppro T r for , o put tion t ni u s w r dopt d to d t r in t st g p rfor n T is stud n d t rst st g p rfor n of n xi ow tur in , using o put tion too for si u ting t st d st t two t r di nsion vis ous ow o put tion uid d n i s softw r w s us d to so v t r ns u tions wit t sp rt r s tur u n od T o put tion uid d n i s r su ts w r o p r d wit t os o t in d fro t n in oss od od T o p risons v n ondu t d to provid pr t st p rfor n for t tur in rst st g


H:
Total enthalpy S: Scalar measure of the deformation tensor T: Temperature T 2 : Temperature at exit of stage d: Distance from the wall f v1 , f v2 , f w : Empirical functions in the turbulence model k K: Constant in the turbulence model p: Pressure s t: Time u: Velocity component in a Cartesian system x: Cartesian coordinate g,r,S : Density ij : Shear stress tensor i, j, k in, out : Inlet and exit conditions 0

INTRODUCTION
In the past, the experimental method was the single tool ance of computational techniques in the last 40 years, another at the design point is around ±2%, if one takes into account uncertainty in the numerical methods, models, geometry,

Stage
Vinícius Guimarães Monteiro was to quantify the performance of the turbine at off-design tions were performed using a three-dimensional unsteady uses a combination of the one-dimensional equations of and they were used to help determining the locations of the design and off-design performances of the 3D computational results are consistent with the mean line analysis used in the losses than predicted by the mean line loss correlations and the 3D computational results yield good agreement with the performance must be done at the beginning of an engine satisfy all the operation requirements (design and off-design Despite of 2D CFD approach limitations, it is important to compared with the mean line loss model code ones, which hub to tip of stator blade and rotor blade in the region near parameters calculated by the 3D CFD simulations was made against mean line loss model code results generated by the

COMPUTATIONAL METHODOLOGY
Conservation equations (2) is the rotation tensor and d is the distance from t

BOUNDARY CONDITIONS
t t conditions to the absolute reference frame were applied to the computational cost, due to the numbers of blade rows necesreason, it was chosen the mixing plane approach in the stage The boundary conditions used in the inlet and outlet of 2D Total pressure inlet Total temperature inlet 1,100 K

Turbulent intensity inlet
The walls for 2D and 3D approaches are adiabatic and + are smaller than six for the of the wall is applied appropriately to the turbulent boundary layer, when

NUMERICAL METHODS
The 2D approach was simulated by ANSYS Fluent is coupled, implicit, with a time marching to reach the steady state condition, and taking into account the turbulence effects The 3D approach was simulated by ANSYS CFX soft-CFX software for the 3D simulation, because the software the turbulence effects by Spalart-Allmaras one-equation The algebraic multigrid was employed to accelerate the

MESH GENERATION
The mesh was constructed for two sub-domains, one for In the 2D model, the mesh is composed by quadrilaterals elements near to the blade region, in order to capture high --Figure 1 represents the mesh of all computational domains The mesh constructed in the 3D model is composed by made in regions where there are high gradients normal to the

MEAN LINE LOSS MODEL CODE
The mean line loss model code uses a combination of the one-dimensional equations of motion in the mean line and t from hub to tip in regions near the leading and trailing edges analysis used by the manufacturer in the conceptual design of

RESULTS AND DISCUSSION
The and rotor blades in the 2D simulation, which imply that the law of It will be presented, at the design point operation, the of these parameters calculated by 3D CFD approach was The mean line analysis represents a good comparison tool can be attributed to the fact that the design data do not take

Pressure ratio
The difference between CFD results and design data is mainly due to one-dimensional characteristic of the mean Similar conclusion can be obtained when comparing 2D and 3D

t
The performance maps constructed by CFD simulation The loss model is established by means of applying boundary layer theories, basic thermodynamic equations, and instance, attached blade boundary layers, the loss mechanisms the loss mechanisms are still not clearly understood and edge loss ( Te ), tip leakage loss ( Tip ), end-wall boundary layer loss ( b ),

Numerical
Simulation of Performance of an Axial Turbine First Stage distribution along the blade span, as mentioned by Tomita and The boundary layer effects, in the hub and tip of the blade, are

-
by empirical correlations (Kacker-Okapuu loss model), which et the rotor blade, which reduces the pressure The present study also focused on the performance maps but 3D CFD results are in better agreement with Denton loss et Numerical Simulation of Performance of an Axial Turbine First produce chocking conditions at some point in Chocking conditions happen when the pressure ratio is CONCLUSIONS concludes that the 3D CFD results are consistent with mean line by the CFD simulation and mean line loss model using Denton results are in better agreement with Denton loss model when et

1,* , Edson Luiz Zaparoli 1 , Cláudia Regina de Andrade 1 , Rosiane Cristina de Lima 2
Keywords: xi Tur in s, s Tur in s, o put tion uid n i s, u ri Si u tion, rfor n

Table 2
presents a comparison of design data against 2D