Heuristic optimization of impeller sidewall gaps-based on the bees algorithm for a centrifugal blood pump by CFD

Optimization studies on blood pumps that require complex designs are gradually increasing in number. The essential design criteria of centrifugal blood pump are minimum shear stress with maximal efficiency. The geometry design of impeller sidewall gaps (blade tip clearance, axial gap, radial gap) is highly effective with regard to these two criteria. Therefore, unlike methods such as trial and error, the optimal dimensions of these gaps should be adjusted via a heuristic method, giving more effective results. In this study, the optimal gaps that can ensure these two design criteria with The Bees Algorithm (BA), which is a population-based heuristic method, are investigated. Firstly, a Computational Fluid Dynamics (CFD) analysis of sample pump models, which are selected according to the orthogonal array and pre-designed with different gaps, are performed. The dimensions of the gaps are optimized through this mathematical model. The simulation results for the improved pump model are nearly identical to those predicted by the BA. The improved pump model, as designed with the optimal gap dimensions so obtained, is able to meet the design criteria better than all existing sample pumps. Thanks to the optimal gap dimensions, it has been observed that compared to average values, it has provided a 42% reduction in aWSS and a 20% increase in efficiency. Moreover, original an approach to the design of impeller sidewall gaps was developed. The results show that computational costs have been significantly reduced by using the BA in blood pump geometry design.

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Flow Visualization Study to Obtain Suitable Design Criteria of a Centrifugal Blood Pump

Heart Replacement ◽

10.1201/b14731-31 ◽

2001 ◽

pp. 311-315 ◽

Cited By ~ 1

Author(s):

M Nishida ◽

T Yamane ◽

T Masuzawa ◽

T Tsukiya ◽

Y Taenaka ◽

...

Keyword(s):

Flow Visualization ◽

Blood Pump ◽

Design Criteria ◽

Centrifugal Blood Pump

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709 Flow Visualization Study to Obtain Suitable Design Criteria of a Centrifugal Blood Pump

The Proceedings of Conference of Kanto Branch ◽

10.1299/jsmekanto.2000.6.167 ◽

2000 ◽

Vol 2000.6 (0) ◽

pp. 167-168

Author(s):

Masahiro NISHIDA ◽

Takashi YAMANE ◽

Ahmed AOUIDEF ◽

Masahiro TOYODA ◽

Toru MASUZAWA ◽

...

Keyword(s):

Flow Visualization ◽

Blood Pump ◽

Design Criteria ◽

Centrifugal Blood Pump

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Parametric Study of Blade Tip Clearance, Flow Rate, and Impeller Speed on Blood Damage in Rotary Blood Pump

Artificial Organs ◽

10.1111/j.1525-1594.2009.00754.x ◽

2009 ◽

Vol 33 (6) ◽

pp. 468-474 ◽

Cited By ~ 19

Author(s):

Nahn Ju Kim ◽

Chenguang Diao ◽

Kyung Hyun Ahn ◽

Seung Jong Lee ◽

Marina V. Kameneva ◽

...

Keyword(s):

Flow Rate ◽

Parametric Study ◽

Tip Clearance ◽

Blood Pump ◽

Rotary Blood Pump ◽

Tip Clearance Flow ◽

Blood Damage ◽

Clearance Flow ◽

Blade Tip ◽

Blade Tip Clearance

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Reduction of Tip Clearance Losses in an Axial Turbine by Shaped Design of the Blade Tip Region

Volume 6: Turbo Expo 2007, Parts A and B ◽

10.1115/gt2007-27303 ◽

2007 ◽

Cited By ~ 1

Author(s):

K. Kusterer ◽

N. Moritz ◽

D. Bohn ◽

T. Sugimoto ◽

R. Tanaka

Keyword(s):

Numerical Investigation ◽

Mass Flow ◽

Suction Side ◽

Tip Clearance ◽

Leakage Flow ◽

Pressure Side ◽

Aerodynamic Efficiency ◽

Blade Tip ◽

Radial Gap ◽

Tip Clearance Vortex

Secondary flows and leakage flows lead to complex vortex structures in the flow field inside the passages of the vanes and blades in turbo machines. These result in aerodynamic losses and, thus, reduced efficiency. One of the major vortex structures is the tip clearance vortex, which is generated on the airfoil’s suction side due to the leakage flow through the tip clearance, e.g. between rotating blades and casing. This leakage flow is induced by the pressure difference between pressure and suction side. The tip clearance vortex intensity strongly depends on the amount of tip clearance leakage. Thus, the reduction of this leakage mass flow increases the aerodynamic efficiency of a turbo-machine. In gas turbines, two ways are commonly used to influence the tip leakage flow: contouring of the radial gap either at blade tip or endwall, or changing the blade tip geometry by application of squealers or winglets on the blade tip. In this paper, a numerical investigation on the principle physics of a specific blade tip design is presented. On the pressure side the blades are extended in the tip region comparable to winglets (“hook-shaped”). With this change, the structures of the flow entering the gap between blade tip and casing are influenced to achieve a reduction of the mass flow in the radial gap. In this approach, the contour of the blade on the pressure side surface is shaped smoothly so that only a low increase of the local stresses should be expected and the blade is manufactured in one part. Furthermore, the height of the tip clearance is not affected. The new blade tip design is applied to 2nd and 3rd blade of the axial turbine in a test configuration of a KHI industrial gas turbine. Thus, a multi-stage numerical approach has been selected for the numerical investigation. The numerical model includes the flow path, vanes and blades of the 2nd and 3rd stage. The mixing plane technique is used to couple the blocks computed in stationary system of reference and rotating system of reference. The aerodynamic efficiency of the new designed blade tip in the two-stage arrangement is compared to the original design. It shows that a slight increase can be achieved in the static polytropic efficiency of the turbine configuration. The influence of the new design on the flow structures in the tip clearance region of the blades is analysed in detail to explain the mechanisms that cause the efficiency increase.

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Microhaemodynamics within the blade tip clearance of a centrifugal turbodynamic blood pump

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/09544119jeim352 ◽

2008 ◽

Vol 222 (4) ◽

pp. 573-581 ◽

Cited By ~ 13

Author(s):

J F Antaki ◽

C-G Diao ◽

F-J Shu ◽

J-C Wu ◽

R Zhao ◽

...

Keyword(s):

Tip Clearance ◽

Blood Pump ◽

Blade Tip ◽

Blade Tip Clearance

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Effect of the Tip Clearance on End Wall Heat-Transfer in a HP Turbine

ASME 2013 Turbine Blade Tip Symposium ◽

10.1115/tbts2013-2069 ◽

2013 ◽

Author(s):

Marc H.-O. Biester ◽

Dimitri Karapetrow ◽

Joerg R. Seume

Keyword(s):

Heat Transfer ◽

Aircraft Engine ◽

Tip Clearance ◽

Time Resolved ◽

Velocity Gradients ◽

Blade Tip ◽

High Level ◽

Radial Gap ◽

End Wall ◽

Tip Clearance Vortex

The present investigation analyzes the effect of the extension of the radial gap on the heat transfer at the blade tip and the casing within a high-pressure turbine stage of an aircraft engine. Due to the rotation and the interaction of the adjacent blade-rows, the flow field in the tip region of an unshrouded rotor-blade is characterized by a high level of unsteadiness. Furthermore, the casing is exposed to the passing blade-gap and corresponding changes in the velocity-profile, the resulting near-wall velocity-gradients, and the resulting changes in heat transfer. In order to account for these effects, time-resolved RANS computations of three different radial gaps are performed and evaluated. The present analysis shows an influence of the radial gap on the characteristics of the steady and unsteady heat transfer and a correlation with the size of the tip-clearance vortex can be shown.

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Experimental and Computational Studies of the Relative Flow Field in a Centrifugal Blood Pump

Critical Reviews in Biomedical Engineering ◽

10.1615/critrevbiomedeng.v28.i12.200 ◽

2000 ◽

Vol 28 (1-2) ◽

pp. 119-125 ◽

Cited By ~ 4

Author(s):

B. T. H. Ng ◽

Weng Kong Chan ◽

S. C. M. Yu ◽

HaiDong Li

Keyword(s):

Flow Field ◽

Blood Pump ◽

Computational Studies ◽

Centrifugal Blood Pump ◽

Relative Flow

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Creep-Based Reliability Evaluation of Turbine Blade-Tip Clearance with Novel Neural Network Regression

Materials ◽

10.3390/ma12213552 ◽

2019 ◽

Vol 12 (21) ◽

pp. 3552 ◽

Cited By ~ 1

Author(s):

Chun-Yi Zhang ◽

Jing-Shan Wei ◽

Ze Wang ◽

Zhe-Shan Yuan ◽

Cheng-Wei Fei ◽

...

Keyword(s):

Neural Network ◽

High Pressure ◽

Reliability Analysis ◽

Response Surface ◽

Response Surface Method ◽

Tip Clearance ◽

Strong Nonlinearity ◽

Surface Method ◽

Blade Tip ◽

Blade Tip Clearance

To reveal the effect of high-temperature creep on the blade-tip radial running clearance of aeroengine high-pressure turbines, a distributed collaborative generalized regression extremum neural network is proposed by absorbing the heuristic thoughts of distributed collaborative response surface method and the generalized extremum neural network, in order to improve the reliability analysis of blade-tip clearance with creep behavior in terms of modeling precision and simulation efficiency. In this method, the generalized extremum neural network was used to handle the transients by simplifying the response process as one extremum and to address the strong nonlinearity by means of its nonlinear mapping ability. The distributed collaborative response surface method was applied to handle multi-object multi-discipline analysis, by decomposing one “big” model with hyperparameters and high nonlinearity into a series of “small” sub-models with few parameters and low nonlinearity. Based on the developed method, the blade-tip clearance reliability analysis of an aeroengine high-pressure turbine was performed subject to the creep behaviors of structural materials, by considering the randomness of influencing parameters such as gas temperature, rotational speed, material parameters, convective heat transfer coefficient, and so forth. It was found that the reliability degree of the clearance is 0.9909 when the allowable value is 2.2 mm, and the creep deformation of the clearance presents a normal distribution with a mean of 1.9829 mm and a standard deviation of 0.07539 mm. Based on a comparison of the methods, it is demonstrated that the proposed method requires a computing time of 1.201 s and has a computational accuracy of 99.929% over 104 simulations, which are improvements of 70.5% and 1.23%, respectively, relative to the distributed collaborative response surface method. Meanwhile, the high efficiency and high precision of the presented approach become more obvious with the increasing simulations. The efforts of this study provide a promising approach to improve the dynamic reliability analysis of complex structures.

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Influence of tip clearance and cavity depth on heat transfer in a cutback squealer tip

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410020964690 ◽

2020 ◽

pp. 095441002096469

Author(s):

Weijie Wang ◽

Shaopeng Lu ◽

Hongmei Jiang ◽

Qiusheng Deng ◽

Jinfang Teng ◽

...

Keyword(s):

Heat Transfer ◽

Suction Side ◽

High Heat ◽

Tip Clearance ◽

Tip Leakage Flow ◽

Trailing Edge ◽

Cavity Depth ◽

High Heat Transfer ◽

Blade Tip ◽

High Heat Transfer Coefficient

Numerical simulations are conducted to present the aerothermal performance of a turbine blade tip with cutback squealer rim. Two different tip clearance heights (0.5%, 1.0% of the blade span) and three different cavity depths (2.0%, 3.0%, and 6.0% of the blade span) are investigated. The results show that a high heat transfer coefficient (HTC) strip on the cavity floor appears near the suction side. It extends with the increase of tip clearance height and moves towards the suction side with the increase of cavity depth. The cutback region near the trailing edge has a high HTC value due to the flush of over-tip leakage flow. High HTC region shrinks to the trailing edge with the increase of cavity depth since there is more accumulated flow in the cavity for larger cavity depth. For small tip clearance cases, high HTC distribution appears on the pressure side rim. However, high HTC distribution is observed on suction side rim for large tip clearance height. This is mainly caused by the flow separation and reattachment on the squealer rims.

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