A Numerical Investigation of Transonic Axial Compressor Rotor Flow Using a Low-Reynolds-Number k–ε Turbulence Model

Abstract

We have developed a computer simulation code for three-dimensional viscous flow in turbomachinery based on the time-averaged compressible Navier–Stokes equations and a low-Reynolds-number k–ε turbulence model. It is described in detail in this paper. The code is used to compute the flow fields for two types of rotor (a transonic fan NASA Rotor 67 and a transonic axial compressor NASA rotor 37), and numerical results are compared to experimental data based on aerodynamic probe and laser anemometer measurements. In the case of Rotor 67, calculated and experimental results are compared under the design speed to validate the code. The calculated results show good agreement with the experimental data, such as the rotor performance map and the spanwise distribution of total pressure, total temperature, and flow angle downstream of the rotor. In the case of Rotor 37, detailed comparisons between the numerical results and the experimental data are made under the design speed condition to assess the overall quality of the numerical solution. Furthermore, comparisons under the part-speed condition are used to investigate a flow field without passage shock. The results are well predicted qualitatively. However, considerable quantitative discrepancies remain in predicting the flow near the tip. In order to assess the predictive capabilities of the developed code, computed flow structures are presented with the experimental data for each rotor and the cause of the discrepancies is discussed.

Application and comparison of SST model in numerical simulation of the axial compressors

“…This rotor has 36 blades, nominal speed 17188.7 r/min, and a design pressure ratio of 2.106 at a mass flow of 20.19 kg·s −1 .This test case has been computed by numerous researchers. Various theoretical predictions from different codes [15][16][17][18][19] and detailed experimental data [20,21] will be very useful in calibrating numerical tools. Therefore, Rotor 37 is preferred as a test case to assess the predictive capabilities of turbomachinery CFD tools.…”

Structure optimization of neural networks for evolutionary design optimization

“…For a clearer comparison, Figure 2 depicts almost the same values, but averaged over all individuals in one generation; as only the controlled generations (i.e., the generations in which the CFD simulations are conducted) are considered, the horizontal axis approximately scales with the amount of computation. ApxN N (1) ApxN N (2) ApxN N (3) ApxN N (1) Figure 2: Results normalized to the number of controlled generations (i.e., proportional to the number of CFD evaluations)…”

“…The second type of NN models (ApxN N (2) ) are obtained using evolutionary structure optimization, as discussed in Section 2.1, i.e., the NNs are optimized with regard to the approximation accuracy of all data points collected during the first seven control cycles of a different evolutionary run. The third type of models (ApxN N (3) ) result from using structure optimization with respect to its learning ability for ν = 7 different problems stemming from the first control cycles of a different design optimization trial; we use the value γ = 0.5 in the averaged Lamarckian inheritance (1). For all types of models, after η generations of each control cycle in the design optimization online adaptation of the weights is performed for τ = 50 iRprop + iterations.…”

“…The performance of each blade is evaluated based on computational fluid dynamics (CFD) simulations. Navier-Stokes equations with the (k − ) turbulence model are used for the two-dimensional CFD simulation [1].…”

Real-World Applications of Multiobjective Optimization

“…In our work, a 3D Navier-Stokes flow solver, HSTAR3D (Arima et al, 1999) is employed, which usually takes from two to four hours on an AMD Opteron 2 GHz double processor depending on the convergence speed of the fluid dynamics. To reduce computation time, a two-level parallel computing architecture has been adopted.…”