İncebay, Ömer

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https://hdl.handle.net/20.500.13091/11693
Name Variants
İncebay, Ö.
Incebay, O.
Incebay, Omer
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Email Address
oincebay@ktun.edu.tr
Main Affiliation
02.10. Department of Mechanical Engineering
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Current Staff
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0000-0002-0056-7619
Scopus Author ID
57224570636
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4AF99AE64018869E
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dXsH_ToAAAAJ
WoS Researcher ID
ABF-9552-2021

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Advanced Structured Materials1
Computer Methods and Programs in Biomedicine1
INTERNATIONAL JOURNAL OF ARTIFICIAL ORGANS1
Journal of Artificial Organs1
Medicine in Novel Technology and Devices1
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  • Thumbnail Image
    Article
    Citation - WoS: 1
    Citation - Scopus: 2
    Computational Fluid Dynamics Simulating of the Fda Benchmark Blood Pump With Different Coefficient Sets and Scaler Shear Stress Models Used in the Power-Law Hemolysis Model
    (Springer Japan Kk, 2025) Önder, Ahmet; İncebay, Ömer; Yapıcı, Rafet
    Hemolysis is the most important issue to consider in the design and optimization of blood-contacting devices. Although the use of Computational Fluid Dynamics (CFD) in hemolysis prediction studies provides convenience and has promising potential, it is an extremely challenging process. Hemolysis predictions with CFD depend on the mesh, implementation method, coefficient set, and scalar-shear-stress model. To this end, an attempt was made to find the combination that would provide the most accurate result in hemolysis prediction with the commonly cited power-law based hemolysis model. In the hemolysis predictions conducted using CFD on the Food and Drug Administration (FDA) benchmark blood pump, 3 different scalar-shear-stress models, and 5 different coefficient sets with the power-law based hemolysis model were used. Also, a mesh independence test based on hemolysis and pressure head was performed. The pressure head results of CFD simulations were compared with published pressure head of the FDA benchmark blood pump and a good agreement was observed. In addition, results of CFD-hemolysis predictions which are conducted with scalar-shear-stress model and coefficient set combinations were compared with experimental hemolysis data at three operating conditions such as 6-7 L/min flow rates at 3500 rpm rotational speeds and 6 L/min at 2500 rpm. One of the combinations of the scalar-shear-stress model and the coefficient set was found to be within the error limits of the experimental measurements, while all other combinations overestimated hemolysis.
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    Doctoral Thesis
    Bir Kalp Destek Pompasının Geometrik Optimizasyonu
    (Konya Teknik Üniversitesi, 2024) İncebay, Ömer; Yapıcı, Rafet
    Kalp yetmezliği olan hastaların tedavisi için kullanılmak üzere geleneksel metotlarla tasarlanan rotadinamik kalp destek pompalarında kinik uygulamalarda karşılaşılan problemlerden dolayı, onların tasarımında iyileştirme çalışmalarına ihtiyaç duyulmaktadır. Bu iyileştirme çalışmalarında verim ve kırmızı kan hücrelerinin hasarı azaltılmaya çalışılmaktadır. Bu çalışmada geleneksel yöntemlerle tasarlanmış santrifüj bir kalp destek pompasının hemoliz indeksi ve hidrolik verim açılarından iyileştirilmesi amaçlanmıştır. Bu amaçla, santrifüj kan pompaları üzerine hemoliz indeksi tahmin metotları üzerine çalışma yapılmıştır. Hemoliz indeksi tahmininde yaygın olarak kullanılan Euler yaklaşımıyla Power-Law modelinde kullanılacak kat sayı setleri, viskozite tanımı ve hesaplamalı akışkanlar dinamiğinde (HAD) kullanılacak türbülans modelleri karşılaştırılmıştır. Bu karşılaştırma çalışmaları sonucunda deneysel sonuçlarla en yakın uyumu veren kat sayı seti, viskozite tanımı ve türbülans modeli belirlenip çalışmanın ilerleyen aşamalarında uygulanmıştır. Optimizasyon çalışmasında hidrolik verim ve hemoliz indeksi üzerinde en yoğun etkiye sahip olduğu değerlendirilen 7 geometrik parametre seçilmiş, bu geometrik parametrelerin alt ve üst sınırları belirlenerek arama bölgesi oluşturulmuştur. Bu arama bölgesi içinde 183 örnek pompa oluşturulmuş ve HAD simülasyonları yapılmıştır. HAD simülasyonlarından elde edilen hemoliz indeksi ve hidrolik verim sonuçları kullanılarak pompanın uyarlanabilir nöro-bulanık çıkarım sistemi (ANFIS) modeli elde edilmiştir. Optimizasyon çalışması, bu ANFIS modelleri kullanılarak genetik algoritma (GA) ile yapılmıştır. GA ile bulunan optimum boyutlara sahip pompa modeli ANSYS Fluent ile simüle edilmiş ve elde edilen sonuçlar temel pompanın simülasyon sonuçları ile karşılaştırılmıştır. Optimizasyon sonucunda, temel pompanın hemoliz indeksi açısından %3,9 ve hidrolik verim açısından %8,7 oranında iyileştirildiği görüldü. Optimum pompa ile temel pompa tasarım devri dışında da karşılaştırıldı. Denenen tüm devirlerde optimum pompanın hem hemoliz indeksi hem hidrolik verim hem de basınç farkı açılarından temel pompadan %1,7 ile %8,7 arasında değişen seviyelerde daha iyi olduğu görüldü. Aynı şekilde tasarım debisi dışında da karşılaştırmalar yapıldı ve yine denenen her debi değerinde de optimum pompanın %1,7 ile %8,7 arasında değişen seviyelerde daha yüksek performanslı olduğu tespit edilmiştir. Optimum pompanın çarkının eğri, konik ve düz olmak üzere üç farklı örtü (kapak) tipine sahip olan versiyonları HAD ile simüle edilip karşılaştırılmıştır. Bu denemelerde çarkı konik örtülü olan versiyon eğri örtülü çarka sahip versiyondan hemoliz indeksi açısından %2,8, hidrolik verim açısından %2,7 daha yüksek performans göstermiştir
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    Article
    Citation - Scopus: 2
    Geometric Optimization of a Blood Pump Impeller Using the Taguchi Method: Cfd Analysis and Experimental Evaluation
    (Elsevier, 2025) Diallo, Abdoulaye Billo; Yapici, Rafet; Incebay, Omer; Cinar, Hasan
    Rotodynamic Left Ventricular Assist Devices (LVADs) are critical in managing severe heart failure by providing mechanical circulatory support. Improving these blood pumps'efficiency is crucial for both lowering the device's energy consumption and enhancing patient comfort. In this study, the efficiency of a reference centrifugal blood pump was improved through geometric optimization and validated using computational fluid dynamics (CFD) simulations and experiments. The number of blades, inlet width, outlet width, inlet angle, and outlet angle are among the important impeller parameters that were optimized at three different levels. The orthogonal array of the Taguchi design method was used to reduce the 243 possible configurations from the full-factorial experimental design to 27 trial tests. Analysis of Variance (ANOVA) was used to determine the optimal geometric parameters, which led to maximum efficiency after S/N ratios were analyzed using MINITAB-18 software. The performance of the optimized pump was evaluated via CFD at 3300, 3150, and 3450 pump rotation speeds, resulting in a 21% increase in hydraulic efficiency at the design point (5 L/min, 3300 rpm, and 128.515 mm-Hg). Furthermore, experimental results demonstrated reduced power consumption for the optimized pump compared to the reference pump. This study highlights the potential of geometric optimization in advancing the performance of rotodynamic LVADs.
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    Article
    Citation - WoS: 8
    Citation - Scopus: 9
    An Experimental Performance Comparison of Newtonian and Non-Newtonian Fluids on a Centrifugal Blood Pump
    (Sage Publications Ltd, 2022) Önder, Ahmet; Yapıcı, Rafet; İncebay, Ömer
    The use of substitute fluid with similar rheological properties instead of blood is important due to ethical concerns and high blood volume consumption in pump performance test before clinical applications. The performance of a centrifugal blood pump with hydrodynamic journal bearing is experimentally tested using Newtonian 40% aqueous glycerin solution (GS) and non-Newtonian aqueous xanthan gum solution of 600 ppm (XGS) as working fluids. Experiments are performed at four different rotational speeds which are 2700, 3000, 3300, and 3600 rpm; experiments using GS reach between 8.5% and 37.2% higher head curve than experiments using the XGS for every rotational speed. It was observed that as the rotational speed and flow rate increase, the head curve difference between GS and XGS decreases. This result can be attributed to the friction reduction effect when using XGS in experiments at high rotation speed and high flow rate. Moreover, due to different fluid viscosities, differences in hydraulic efficiency were observed for both fluids. This study reveals that the use of Newtonian fluids as working fluids is not sufficient to determine the actual performance of a blood pump, and the performance effects of non-Newtonian fluids are remarkably important in pump performance optimizations.
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    Article
    Farklı Tiplerdeki Çark Kanatlarının Santrifüj Kalp Destek Pompa Performansına Etkisinin Sayısal Olarak İncelenmesi
    (2021) Usca, Üsame Ali; Uzun, Mahir; Yapıcı, Rafet; İncebay, Ömer
    Bu çalışmada, kalp yetmezliği hastalıklarında tedaviye destek amaçlı olarak kullanılan santrifüj kalp destek pompaları için farklı çark kanat geometrilerinin pompa performansına olan etkisi sayısal olarak incelenmiştir. Pompa tasarım parametreleri olarak, yetişkin bir insan kalbinin çalışma parametreleri baz alınmıştır. Bu parametreler ışığında pompa tasarımı yapılmış ve CFD (Computational Fluid Dynamics) yazılımı aracılığıyla 3 farklı çark kanat tipi için (radyal, eğik ve eğri) dört farklı debide (3, 4, 5 ve 6 l/dk.) ve üç farklı dönme hızında (3500, 3850 ve 4250 dev/dk.) pompa performansları tespit edilerek pompa performans eğrileri oluşturulmuştur. Elde edilen bulgulara göre tasarım noktası parametrelerine, eğri çark tipinde ve 3850 dev/dk. dönme hızında ulaşılmıştır. Bu noktada pompa hidrolik verimi ise %34 olarak tespit edilmiştir. En yüksek basınç farkı yaklaşık 180 mm-Hg ve 2 l/dk. debide elde edilmiştir. Ayrıca bu çalışmada parametrelerin ve çark kanat tiplerinin kan hasarına (hemoliz) olan etkilerini inceleyebilmek için cidar kayma gerilmeleri de tespit edilmiştir.
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    Article
    Citation - WoS: 10
    Citation - Scopus: 14
    Heuristic Optimization of Impeller Sidewall Gaps-Based on the Bees Algorithm for a Centrifugal Blood Pump by Cfd
    (SAGE PUBLICATIONS LTD, 2021) Önder, Ahmet; İncebay, Ömer; Şen, Muhammed Arif; Yapıcı, Rafet; Kalyoncu, Mete
    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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    Book Part
    Experimental Investigation of the Overall Efficiency of a Centrifugal Blood Pump Using Glycerin Solution and Xanthan Gum Solutions as Blood Analog Fluid
    (Springer, 2025) Onder, A.; Incebay, O.; Yapici, R.
    The most critical issues to consider in the design of the blood pumps are the hydraulic performance and hemocompatibility of the pump. It is important to perform hydraulic performance tests during the blood pump development process before clinical applications. Using substitute fluids instead of blood as the working fluid during the testing of blood pumps provides convenience for the tests. In this study, solid models of all components of a centrifugal blood pump were designed, and then the pump volute and impeller were manufactured. The hydraulic performance of the manufactured centrifugal blood pump is experimentally tested using an aqueous glycerin solution and xanthan gum solution as working fluids. The overall efficiency of the pump at four rotation speeds which are 2700, 3000, 3300, and 3600 rpm was determined for both fluids. Experiments were carried out in the flow rate range of 1–8 L/min. The experimental overall efficiencies of the two working fluids were compared at all rotational speeds and throughout the flow rate range. As a result of the study, there were approximately 2% differences in overall efficiency for the two working fluids at the same rotational speeds and flow rates. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.
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    Article
    Citation - WoS: 6
    Citation - Scopus: 7
    Fuzzy-Based Modeling and Speed Optimization of a Centrifugal Blood Pump Using a Modified and Constrained Bees Algorithm
    (Elsevier Ireland Ltd, 2022) İncebay, Ömer; Önder, Ahmet; Arif, Şen, Muhammed; Yapıcı, Rafet; Kalyoncu, Mete
    Background and objective: Side effects that may occur when using blood pumps for treatment of patients are the main limitations on pump rotational speed determination. Efforts are being made to reduce side effects in both design and usage procedures. In determining the pump speed for treatment, decreasing the pressure on the main artery and preserving the valve functions are taken into consideration. In addition to these, the parameters considered for design which include pump efficiency and mechanical effects on blood cells, should also be taken into consideration. In this study, the aim is to obtain the optimum pump speed for the maximum hydraulic efficiency and minimum wall shear stresses that occur inside the pump. Methods: Blood pump modeling based on fuzzy logic is created on the hydraulic performance data of a centrifugal blood pump, whose design, CFD analysis, manufacture and experimental testing have been performed previously. Using this fuzzy logic model, the optimum pump speeds were determined using the Bees Algorithm, an intuitive optimization algorithm, in the operating range 1-7 L/min fluid flow rate. In the optimization process, the aim is to achieve minimum shear stress with maximal efficiency. Intravascular pressure limits (90-160 mm-Hg) were set as pressure constraints. Results: The optimum operating point is obtained as a 3350 rpm pump speed and a 4.35 L/min flow rate. At this operating point, CFD simulation is performed, and maximum wall shear stress was found to be 1458 Pa and its efficiency as 34.2%. Conclusions: In addition to the parameters commonly used in the pump speed optimization of blood pumps, the use of wall shear stresses and pump efficiency can provide certain improvements. © 2022