Hydraulic Design of Hydraulic Turbine based on Blade Loading Control through Three-Dimensional Inverse Design Method

Author(s):  
Yan Xia ◽  
Wei Yang
Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3210
Author(s):  
Wei Yang ◽  
Benqing Liu ◽  
Ruofu Xiao

Hydraulic machinery with high performance is of great significance for energy saving. Its design is a very challenging job for designers, and the inverse design method is a competitive way to do the job. The three-dimensional inverse design method and its applications to hydraulic machinery are herein reviewed. The flow is calculated based on potential flow theory, and the blade shape is calculated based on flow-tangency condition according to the calculated flow velocity. We also explain flow control theory by suppression of secondary flow and cavitation based on careful tailoring of the blade loading distribution and stacking condition in the inverse design of hydraulic machinery. Suggestions about the main challenge and future prospective of the inverse design method are given.


Author(s):  
Duccio Bonaiuti ◽  
Abeetha Pitigala ◽  
Mehrdad Zangeneh ◽  
Yansheng Li

In the present paper, the redesign of a transonic rotor was performed by means of a three-dimensional viscous inverse design method. The inverse approach used in this work is one where the pressure loading, blade thickness distribution and stacking axis are specified and the camber surface is calculated accordingly. The design of transonic and supersonic axial compressors strongly relies on the ability to control the shock strength, location and structure. The use of an inverse design method allows one to act directly on aerodynamic parameters, like the blade loading, and provides an efficient tool to control the shock wave and its interaction with the boundary and secondary flows and with the tip clearance vortex. In the present study, the parametric investigation of the blade loading distribution was carried out. Few design parameters, with immediate physical meaning, were required to control the three-dimensional blade loading, and their impact on the design and off-design performance of the rotor was assessed by means of CFD calculations. Further investigations were then performed in order to study the impact on the rotor performance of the geometrical parameters (meridional channel and thickness distribution), which must be imposed in the design with the inverse method. As a result, it was possible to develop guidelines for the aerodynamic design of transonic rotors that can be exploited for similar design applications.


Author(s):  
Kosuke Ashihara ◽  
Akira Goto

Numerical and experimental investigations were performed to study the effects of blade loading on pump inducer performance and flow fields. To compare the performance of inducers with different blade loadings, a three-dimensional inverse design method was applied to control the blade loading distribution of inducers. Firstly, a conventional helical inducer was designed. The blade number is three and the blade angle at the tip was chosen by the conventional design method. Then, two inducers were designed using a three-dimensional inverse design method with different blade loading distributions. One inducer was designed with fore-loading and the other was designed with aft-loading, but both inducers were designed with no leading edge loading. These two inducers have the same design specification as the conventional helical inducer. The CFD (Computational Fluid Dynamics) analyses and water model tests were performed on these three inducers. Both results showed that the inlet backflow characteristics of the 3-D inverse design inducers are improved from those of the conventional inducer. It was also found that the inlet backflow characteristics of inducers that have no leading edge loading are almost same despite different blade loading distributions. The inducer designed with fore-loading showed almost the same suction performance as the conventional inducer. Cavitation visualization and FFT analysis of unstable phenomena were also performed in this study.


Author(s):  
Hidenobu Okamoto ◽  
Akira Goto

This paper describes a new design method of blade geometry for a Francis turbine runner by using a three-dimensional inverse design method and the Computational Fluid Dynamics (CFD) technique. The design objectives are the suppression of cavitation by reducing the area in which static pressure is lower than the vapor pressure while keeping the efficiency high. In the inverse design method, it is possible to optimize the static pressure distribution in the runner by controlling blade loading parameters and/or stacking condition, which is related to a blade lean angle, for the same design specification. A Francis turbine runner was re-designed by the inverse design method for different blade loading and stacking conditions, and the flow fields were evaluated by applying CFD. It was confirmed that the present design method is very practical and effective to control low pressure region and achieve high efficiency for Francis turbine runners.


2019 ◽  
Vol 5 (10) ◽  
pp. eaax4769 ◽  
Author(s):  
Alan Zhan ◽  
Ricky Gibson ◽  
James Whitehead ◽  
Evan Smith ◽  
Joshua R. Hendrickson ◽  
...  

Controlling the propagation of optical fields in three dimensions using arrays of discrete dielectric scatterers is an active area of research. These arrays can create optical elements with functionalities unrealizable in conventional optics. Here, we present an inverse design method based on the inverse Mie scattering problem for producing three-dimensional optical field patterns. Using this method, we demonstrate a device that focuses 1.55-μm light into a depth-variant discrete helical pattern. The reported device is fabricated using two-photon lithography and has a footprint of 144 μm by 144 μm, the largest of any inverse-designed photonic structure to date. This inverse design method constitutes an important step toward designer free-space optics, where unique optical elements are produced for user-specified functionalities.


2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Jun-lian Yin ◽  
De-zhong Wang ◽  
Xian-zhu Wei ◽  
Le-qin Wang

For pump turbines, an S-shaped curve can lead to failures in synchronization. To improve the hydraulic design, the component that is responsible for the formation of the S-shaped curve was identified by a hydraulic loss analysis using previous computational fluid dynamics (CFD) results, which indicates that the formation of the S-shaped curve can be ascribed to the runner. To improve the hydraulic design of the runner, a simple numerical approach for direct problem analysis was proposed, based on the blade-loading distributions of runners with and without an S-shaped curve, and directly analyzed. It was implied from the differences in the blade-loading distributions that, when the meridional passage was broadened, the formation of the S-shaped curve was suppressed. To validate this, two runners with different meridional sections were designed by means of the inverse design method. Through model tests, it was verified that the S-shaped curve was eliminated completely and the performance curve of the modified hydraulic model satisfied the requirements for safe operation in a pumped storage plant.


2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Luying Zhang ◽  
Gabriel Davila ◽  
Mehrdad Zangeneh

Abstract This paper presents three different multiobjective optimization strategies for a high specific speed centrifugal volute pump design. The objectives of the optimization consist of maximizing the efficiency and minimizing the cavitation while maintaining the Euler head. The first two optimization strategies use a three-dimensional (3D) inverse design method to parametrize the blade geometry. Both meridional shape and 3D blade geometry are changed during the optimization. In the first approach, design of experiment (DOE) method is used and the pump efficiency is obtained from computational fluid dynamics (CFD) simulations, while cavitation is evaluated by using minimum pressure on blade surface predicted by 3D inverse design method. The design matrix is then used to create a surrogate model where optimization is run to find the best tradeoff between cavitation and efficiency. This optimized geometry is manufactured and tested and is found to be 3.9% more efficient than the baseline with reduced cavitation at high flow. In the second approach, only the 3D inverse design method output is used to compute the efficiency and cavitation parameters and this leads to considerable reduction to the computational time. The resulting optimized geometry is found to be similar to the computationally more expensive solution based on 3D CFD results. In order to compare the inverse design based optimization to the conventional optimization, an equivalent optimization is carried out by parametrizing the blade angle and meridional shape.


Author(s):  
Yujie Zhu ◽  
Yaping Ju ◽  
Chuhua Zhang

Most of the inverse design methods of turbomachinery experience the shortcoming where the target aerodynamic parameters need to be manually specified depending on the designers’ experience and insight, making the design result aleatory and even deviated from the real optimal solution. To tackle this problem, an experience-independent inverse design optimization method is proposed and applied to the redesign of a compressor cascade airfoil in this study. The experience-independent inverse design optimization method can automatically obtain the target pressure distribution along the cascade airfoil through the genetic algorithm, rather than through the manual specification approach. The shape of cascade airfoil is then solved by the adjoint method. The effectiveness of the experience-independent inverse design optimization method is demonstrated by two inverse design cases of the compressor cascade airfoil, i.e. the inverse design of only the suction surface and the inverse design of both the suction and pressure surfaces. The results show that the proposed inverse design method is capable of significantly improving the aerodynamic performance of the compressor cascade. At the examined flow condition, a thin airfoil profile is beneficial to flow accelerations near the leading edge and flow separation avoidance near the trailing edge. The proposed inverse design method is quite generic and can be extended to the three-dimensional inverse design of advanced compressor blades.


2002 ◽  
Vol 124 (2) ◽  
pp. 319-328 ◽  
Author(s):  
Akira Goto ◽  
Mehrdad Zangeneh

A new approach to optimizing a pump diffuser is presented, based on a three-dimensional inverse design method and a Computational Fluid Dynamics (CFD) technique. The blade shape of the diffuser was designed for a specified distribution of circulation and a given meridional geometry at a low specific speed of 0.109 (non-dimensional) or 280 (m3/min, m, rpm). To optimize the three-dimensional pressure fields and the secondary flow behavior inside the flow passage, the diffuser blade was more fore-loaded at the hub side as compared with the casing side. Numerical calculations, using a stage version of Dawes three-dimensional Navier-Stokes code, showed that such a loading distribution can suppress flow separation at the corner region between the hub and the blade suction surface, which was commonly observed with conventional designs having a compact bowl size (small outer diameter). The improvements in stage efficiency were confirmed experimentally over the corresponding conventional pump stage. The application of multi-color oil-film flow visualization confirmed that the large area of the corner separation was completely eliminated in the inverse design diffuser.


Author(s):  
Kosuke Ashihara ◽  
Akira Goto ◽  
Shijie Guo ◽  
Hidenobu Okamoto

In this paper, a new aerodynamic design procedure is presented for a centrifugal compressor stage of a microturbine system. To optimize the three-dimensional (3-D) flows and the performance, an inverse design method, which numerically generates the 3-D blade geometry for specified blade loading distribution, has been applied together with the numerical validation using CFD (Computational Fluid Dynamics) and FEM (Finite Element Method). The blade profile along the shroud surface of the impeller was optimized based on the 3-D inverse design and CFD. However, the blade profile towards the hub surface was modified geometrically to achieve a nearly radial blade element especially at the inducer part of the impeller, in order to meet the required structural strength. The modified impeller successfully kept similar aerodynamic performance as that of a blade with a fully 3-D shape, whilst showing improved structural reliability. So, the proposed method to adopt the blade profile designed by the inverse method along the shroud, and to geometrically modify the blade profile towards the hub, was confirmed to be effective to design a high-speed compressor impeller. The vaned diffuser has also been re-designed using the inverse design method. The corner separation in the conventional wedge-type diffuser channel was suppressed in the new design. The stage performance improvements were confirmed by stage calculations using CFD.


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