A Novel Transonic Fan Swept Outlet Guide Vane Using 3D Design Optimization

Author(s):  
Toyotaka Sonoda ◽  
Giles Endicott ◽  
Toshiyuki Arima ◽  
Markus Olhofer

In our previous work on a transonic fan swept outlet guide vane (OGV) for a small turbofan engine (GT2011-46363), we showed a novel oscillatory casing profile that leads to approximately 20% loss reduction, using a numerical design optimization method. In this paper we analyze the resulting geometry of an optimization based on a blade representation which is able to realize significantly larger surface modifications. The final optimized design displays a novel blade geometry that has its maximum blade thickness at around 80% blade chord (located between the blade’s mid-chord and trailing edge) especially in the mid-span region. The flow physics explaining why this blade geometry without the oscillatory casing profile has the same loss reduction level of more than 20% at the peak efficiency point are discussed, focusing on the secondary flow and span-wise static pressure gradient on the blade suction side.

Author(s):  
Giles Endicott ◽  
Toyotaka Sonoda ◽  
Markus Olhofer ◽  
Toshiyuki Arima

In this paper we follow the process of rapid design improvement for the fan outlet guide vane for a turbofan powering a very light jet. The small size of such engines leads to a low Reynolds number, resulting in flow-fields prone to boundary layer separation, causing significant losses in efficiency. This paper studies experimental testing in a scale rig, and numerical simulation using CFD, leading to the comparison of the two datasets and hence assessment of the numerical technique. The mesh employed by the CFD simulation was modified using Free Form Deformation to create different geometric designs, and hence an optimization scheme was subsequently utilized to find the deformation of 28 variables which maximized aerodynamic performance. The final optimized design displayed a novel oscillatory casing profile, while the blade shape had increased camber relative to the baseline. The improvement in pressure loss was approximately 20% across the range of operating conditions studied.


Author(s):  
Wenlong Zhao ◽  
Jian Zhang ◽  
Xiaodong Yu ◽  
Daqing Zhou ◽  
Melih Calamak

Tubular pumps are widely used in irrigation and water conveyance projects. However, the operating head of most of these pumps is low, and only a few studies have focused on the design of an efficient tubular pump with a head more than 5 m, which is common in long-distance water supply projects. This work aims to improve the operating head and efficiency of tubular pumps while maintaining a low shaft power. The multi-objective orthogonal optimization method was used to determine the critical parameters of the tubular pump, i.e., blade number, airfoil, blade thickness and guide vane distance, and nine design schemes were selected. Next, by using computational fluid dynamics (CFD), a 3D model of the tubular pumps under different schemes was established, and the results were compared. Subsequently, the range method and weighted matrix method were utilized to find the optimized scheme. In addition, an experimental investigation was performed to verify the simulation and the performance of the designed tubular pump. The results indicated that the optimized scheme improved the operating head to 6.9 m with higher efficiency of 84.2% and a lower shaft power of 27.7 kW. The modeling results were in agreement with the experimental measurements, and the designed tubular pump had a wide range of high-efficiency zones.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4045
Author(s):  
David Menéndez Arán ◽  
Ángel Menéndez

A design method was developed for automated, systematic design of hydrokinetic turbine rotor blades. The method coupled a Computational Fluid Dynamics (CFD) solver to estimate the power output of a given turbine with a surrogate-based constrained optimization method. This allowed the characterization of the design space while minimizing the number of analyzed blade geometries and the associated computational effort. An initial blade geometry developed using a lifting line optimization method was selected as the base geometry to generate a turbine blade family by multiplying a series of geometric parameters with corresponding linear functions. A performance database was constructed for the turbine blade family with the CFD solver and used to build the surrogate function. The linear functions were then incorporated into a constrained nonlinear optimization algorithm to solve for the blade geometry with the highest efficiency. A constraint on the minimum pressure on the blade could be set to prevent cavitation inception.


2021 ◽  
Vol 9 (8) ◽  
pp. 831
Author(s):  
Zhuangzhuang Sun ◽  
Jie Yu ◽  
Fangping Tang

In order to study the influence of the position of the bulb on the hydraulic performance of asubmersible tubular pump device, based on a large-scale pumping station, two schemes—involving a front-mounted bulb and a rear-mounted bulb, respectively—were designed. The front-mounted scheme uses the GL-2008-03 hydraulic model and its conventional guide vane, while the rearmounted scheme uses the optimized design of a diffuser vane. The method of combining numerical simulation and experimental testing was used to analyze the differences between the external and internal characteristics of the two schemes. The results show that, under the condition of reasonable diffusion guide vane design, the efficiency under the rear-mounted scheme is higher than that under the front-mounted scheme, where the highest efficiency difference is about 1%. Although the frontmounted bulb scheme reduces the hydraulic loss of the bulb section, the placement of the bulb on the water inlet side reduces the flow conditions of the impeller. Affected by the circulation of the guide vane outlet, the hydraulic loss of the outlet channel is greater than the rear-mounted scheme. The bulb plays a rectifying function when the bulb is placed behind, which greatly eliminates the annular volume of the guide vane outlet, and the water outlet channel has a smaller hydraulic loss. In the front-mounted scheme, the water flow inside the outlet channel squeezes to the outer wall, causing higher entropy production near the outer wall area. The entropy production of the rear-mounted scheme is mainly in the bulb section and the bulb support. This research can provide reference for the design and form selection of a submersible tubular pump device, which has great engineering significance.


Author(s):  
Myung-Jin Choi ◽  
Min-Geun Kim ◽  
Seonho Cho

We developed a shape-design optimization method for the thermo-elastoplasticity problems that are applicable to the welding or thermal deformation of hull structures. The point is to determine the shape-design parameters such that the deformed shape after welding fits very well to a desired design. The geometric parameters of curved surfaces are selected as the design parameters. The shell finite elements, forward finite difference sensitivity, modified method of feasible direction algorithm and a programming language ANSYS Parametric Design Language in the established code ANSYS are employed in the shape optimization. The objective function is the weighted summation of differences between the deformed and the target geometries. The proposed method is effective even though new design variables are added to the design space during the optimization process since the multiple steps of design optimization are used during the whole optimization process. To obtain the better optimal design, the weights are determined for the next design optimization, based on the previous optimal results. Numerical examples demonstrate that the localized severe deviations from the target design are effectively prevented in the optimal design.


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