Axial Flow Hydraulic Turbine Runner Inverse Design Computation by Improved Q3D Inverse Method.

AbstractMetasurfaces have provided unprecedented freedom for manipulating electromagnetic waves. In metasurface design, massive meta-atoms have to be optimized to produce the desired phase profiles, which is time-consuming and sometimes prohibitive. In this paper, we propose a fast accurate inverse method of designing functional metasurfaces based on transfer learning, which can generate metasurface patterns monolithically from input phase profiles for specific functions. A transfer learning network based on GoogLeNet-Inception-V3 can predict the phases of 28×8 meta-atoms with an accuracy of around 90%. This method is validated via functional metasurface design using the trained network. Metasurface patterns are generated monolithically for achieving two typical functionals, 2D focusing and abnormal reflection. Both simulation and experiment verify the high design accuracy. This method provides an inverse design paradigm for fast functional metasurface design, and can be readily used to establish a meta-atom library with full phase span.

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Inverse Design of Axial-Flow Compressor Blades Using Elastic Surface Algorithm in Subsonic and Transonic Flow Regimes With Separation

Volume 2C: Turbomachinery ◽

10.1115/gt2016-56717 ◽

2016 ◽

Author(s):

M. H. Noorsalehi ◽

M. Nili-Ahamadabadi ◽

E. Shirani ◽

M. Safari

Keyword(s):

Pressure Distribution ◽

Transonic Flow ◽

Design Method ◽

Axial Flow ◽

Flow Regimes ◽

Inverse Design ◽

Elastic Surface ◽

Axial Flow Compressor ◽

Inverse Design Method ◽

Flow Compressor

In this study, a new inverse design method called Elastic Surface Algorithm (ESA) is developed and enhanced for axial-flow compressor blade design in subsonic and transonic flow regimes with separation. ESA is a physically based iterative inverse design method that uses a 2D flow analysis code to estimate the pressure distribution on the solid structure, i.e. airfoil, and a 2D solid beam finite element code to calculate the deflections due to the difference between the calculated and target pressure distributions. In order to enhance the ESA, the wall shear stress distribution, besides pressure distribution, is applied to deflect the shape of the airfoil. The enhanced method is validated through the inverse design of the rotor blade of the first stage of an axial-flow compressor in transonic viscous flow regime. In addition, some design examples are presented to prove the effectiveness and robustness of the method. The results of this study show that the enhanced Elastic Surface Algorithm is an effective inverse design method in flow regimes with separation and normal shock.

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Study on an Axial Flow Hydraulic Turbine with Collection Device

International Journal of Rotating Machinery ◽

10.1155/2014/308058 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 3

Author(s):

Yasuyuki Nishi ◽

Terumi Inagaki ◽

Kaoru Okubo ◽

Norio Kikuchi

Keyword(s):

Velocity Ratio ◽

Axial Flow ◽

Hydraulic Turbine ◽

Power Coefficient ◽

Speed Ratio ◽

Maximum Output ◽

Recovery Coefficient ◽

Composite Body ◽

Inlet Velocity ◽

Collection Device

We propose a new type of portable hydraulic turbine that uses the kinetic energy of flow in open channels. The turbine comprises a runner with an appended collection device that includes a diffuser section in an attempt to improve the output by catching and accelerating the flow. With such turbines, the performance of the collection device, and a composite body comprising the runner and collection device were studied using numerical analysis. Among four stand-alone collection devices, the inlet velocity ratio was most improved by the collection device featuring an inlet nozzle and brim. The inlet velocity ratio of the composite body was significantly lower than that of the stand-alone collection device, owing to the resistance of the runner itself, the decreased diffuser pressure recovery coefficient, and the increased backpressure coefficient. However, at the maximum output tip speed ratio, the inlet velocity ratio and the loading coefficient were approximately 31% and 22% higher, respectively, for the composite body than for the isolated runner. In particular, the input power coefficient significantly increased (by approximately 2.76 times) owing to the increase in the inlet velocity ratio. Verification tests were also conducted in a real canal to establish the actual effectiveness of the turbine.

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