Profile URL: https://hdl.handle.net/20.500.13091/11872
Job Title:Prof. Dr.
Email Address:ryapici@ktun.edu.tr
Main Affiliation:02.10. Department of Mechanical Engineering
Status: Current Staff
ORCID:
0000-0002-1109-7480
0000-0002-1109-7480Scopus ID:
16044036400
16044036400YÖK Akademik: F5944812B6594B36
Google Scholar:
iZYEnJsAAAAJ
iZYEnJsAAAAJWeb of Science ID:
GKR-4365-2022
GKR-4365-2022Name Variants:
Yapici, Rafet
19 results
Scholarly Output Search Results
Now showing 1 - 10 of 19
Master Thesis Hesaplamalı Akışkan Dinamiği ile Santrifüj Bir Kalp Destek Pompasının Optimizasyonu(Konya Teknik Üniversitesi, 2020) Diallo, Abdoulaye Billo; Yapıcı, RafetBu tez çalışmasının ilk kısmında, Taguchi yöntemini kullanarak referans bir santrifüj kalp destek pompasının veriminin iyileştirilmesi üzerine çalışıldı. Üç seviyede referans pompanın beş geometrik parametresi optimize edildi. Geometrik parametrelerinin optimizasyonunda, 5 L/dak debi ile 3150, 3300 ve 3450 dev/dak dönme sayıları kullanıldı. Elde edilen verim sonuçlarından sinyal/gürültü değerleri hesaplandı ve varyans analizleri yapıldı. Optimal pompanın geometrik parametreleri, ortalama S/N'nin maksimum değerleri dikkate alınarak elde edildi. Elde edilen optimum pompanın katı modeli oluşturuldu ve HAD simülasyonları yapılarak optimal pompanın performansı belirlendi. Sonuçta referans pompanın veriminin epeyce iyileştirilebileceği anlaşıldı. Çalışmanın ikinci kısmında, 0.002-0.006 kg/m.s aralığında viskozitedeki değişimin pompa hidrolik performansına etkileri araştırıldı. Araştırma sonunda viskozite artışına bağlı olarak; sabit debide toplam basınç farkında azalma ve pompa gücünde artma gözlemlendi. Sonuç olarak vizkozite arttıkça pompa veriminde kayda değer bir azalma olduğu görüldü. Bu çalışmanın son kısmında, optimizasyon çalışmasını sonucunda tasarlanan optimum pompanın ve referans pompanın prototipi üretildi ve onlar su-gliserin çözeltisi kullanılarak deneysel testlere tabi tutuldu. Bu pompaların hidrolik performansları belirlendi ve kıyaslandı. Optimum pompanın basınç farkı ve veriminin referans pompanınkinden daha iyi olduğu görüldü.Master Thesis Newton Tipi Olmayan Akışkan Kullanarak Kalp Destek Pompası Performansının Sayısal ve Deneysel Olarak Belirlenmesi(Konya Teknik Üniversitesi, 2019) Sabah, Ahmet Mete; Yapıcı, RafetKalp rahatsızlıkları içerisinde önemli bir yere sahip olan kalp yetmezliği, insan kalbinin çeşitli nedenlerden dolayı vücuda ihtiyaç duyduğu yeterli kanı pompalayamaması durumudur. Bu hastalığa sahip bireylere yardımcı olmak amacıyla ventriküler (karıncık) destek cihazları (VAD) adı verilen mekanik sistemler geliştirilmiştir. Sol ventriküler destek cihazları, kalbin sol karıncığından kanın aort atar damarına pompalamasına yardımcı olmaktadır. Bu çalışmada, tasarlanmış olan karışık akışlı bir sol ventriküler kalp destek pompasının hidrodinamik preformansı hesaplamalı akışkanlar dinamiği (HAD) metodu ve deneysel çalışmalar ile belirlendi. Analizlerde çalışma akışkanı olarak kana benzer reolojik özellikler gösteren newton tipi olmayan ksantan-su karışımı (kütlece %0,06 ksantan sakızı) kullanıldı. 5000, 6000 ve 7000 dev/dak dönme hızlarında pompanın debisine bağlı olarak basıncını ve verimini gösteren performans eğrileri elde edildi. Sonuçların karşılaştırılması amacıyla newton tipi bir akışkan olan su-gliserin çözeltisi (hacimce %40 gliserin ve %60 su) ile de HAD analizleri ve deneysel çalışmalar yapıldı. Pompa, deneysel çalışma ve sayısal analiz sonuçlarına göre 5 L/dak debide 5000 dev/dak dönme hızında 88,39 mmHg basınç farkı değerine ulaşmıştır. Bu noktadaki pompa hidrolik verimi %52,74, genel verimi ise %18,45 olarak belirlendi.Article Citation - WoS: 8Citation - Scopus: 9An Experimental Performance Comparison of Newtonian and Non-Newtonian Fluids on a Centrifugal Blood Pump(Sage Publications Ltd, 2022-01-11) Önder, Ahmet; Yapıcı, Rafet; İncebay, ÖmerThe 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.Article Citation - Scopus: 2Geometric Optimization of a Blood Pump Impeller Using the Taguchi Method: Cfd Analysis and Experimental Evaluation(Elsevier, 2025-06-01) Diallo, Abdoulaye Billo; Yapici, Rafet; Incebay, Omer; Cinar, HasanRotodynamic 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.Article Farklı Tiplerdeki Çark Kanatlarının Santrifüj Kalp Destek Pompa Performansına Etkisinin Sayısal Olarak İncelenmesi(Pamukkale Univ, 2021) Usca, Üsame Ali; Uzun, Mahir; Yapıcı, Rafet; İncebay, ÖmerBu 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.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.Article Citation - WoS: 1Citation - Scopus: 2FUZZY LOGIC-BASED MODELING OF A CENTRIFUGAL BLOOD PUMP PERFORMANCE VIA EXPERIMENTAL DATA OF NEWTONIAN AND NON-NEWTONIAN FLUIDS(World Scientific Publ Co Pte Ltd, 2022) Önder, Ahmet; Güzel, Muhammed Huseyin; İncebay, Omer; Sen, Muhammed Arif; Yapıcı, Rafet; Kalyoncu, MeteUsing fuzzy logic methods, some complex experiments that are not possible due to critical limitations can be simulated in a short time. In this study, experimental data of Newtonian 40% aqueous glycerin solution (GS) and non-Newtonian 600ppm aqueous xanthan gum solution (XGS) working fluids were used to model the hydraulic performance of a centrifugal blood pump. A novel fuzzy logic-based model (FLM) for modeling the hydraulic performance of the pump model is proposed. In the proposed model, there are two inputs which are flow rate and impeller rotational speed and one output which is head pressure. In FLM, the range for flow rate is 1-7.8L/min in GS and 1-8L/min in XGS, and for head pressure 50-245mmHg in GS and 50-215mmHg in XGS. In addition, impeller rotational speed range is 2700-3600rpm for both fluids. The estimated results with FLM were validated with the experimental results and it was seen that the FLM was compatible with the experimental results with an accuracy of 96.25%. These results imply that the developed FLM is acceptable and can be used to assist in determining the performance of blood pumps.Article Citation - WoS: 10Citation - Scopus: 14Heuristic Optimization of Impeller Sidewall Gaps-Based on the Bees Algorithm for a Centrifugal Blood Pump by Cfd(SAGE PUBLICATIONS LTD, 2021-06-15) Önder, Ahmet; İncebay, Ömer; Şen, Muhammed Arif; Yapıcı, Rafet; Kalyoncu, MeteOptimization 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.Article Experimental Investigation of Absorption and Thermal Analysis of Different Types of Nanoparticles With Motor Oil Based Nanofluids(Konya Teknik Univ, 2023-03-01) Yapıcı, Rafet; Alenezy, Jasim; Hameed, Amar HasanNanofluids are fluid suspensions of nanoparticles that exhibit notable properties enhancement even at low nanoparticle concentrations. This work compares the measured and calculated thermophysical parameters of nanofluidic motor oil. Thermophysical parameters of motor oils include thermal conductivity, viscosity, and Absorbance. The nanofluidic engine oil was prepared by dispersing multi-walled carbon nanotube (MWCNTs) and copper oxide (CuO) at different particle concentrations (0.03-0.12) %. The oil characteristics were measured at wide range of temperature. The viscosity data were found to be comparable to the numbers reported in literature. We found that the thermal conductivity increased up to five times with minor variance in some cases. The variation in thermal conductivity can be related to several reasons such as oil specifications and nanofluid preparation conditions. The measured Absorbance of the nanofluid is comparable to literature and has direct proportion relation with the volume fraction of nanoparticles.Article Citation - WoS: 1Citation - Scopus: 1Analysis of Fluid Forces Impacting on the Impeller of a Mixed Flow Blood Pump With Computational Fluid Dynamics(Sage Publications Ltd, 2024-11-07) Diallo, Abdoulaye Billo; Cinar, Hasan; Yapici, RafetThis study presents four different impeller designs to compare hydrodynamic forces. Numerical simulation studies are performed via computational fluid dynamics to specify and investigate the hydraulic forces impacting the impeller of the mixed-flow blood pump with a volute. The design point of this pump is that the flow rate is 5 L/min, the rotational speed is 8000 rpm, and the manometric head is 100 mmHg. The designed impellers are placed in the same volute and simulation studies are performed with the same mesh size (17.3 million cells) of the pumps. The simulation studies have been conducted in setting 1050 kg/m3 blood density, 35 cP fluid viscosity, and SST-k omega turbulence model. Additionally, this study examines the changes in hydraulic forces and hydraulic efficiency with fluid viscosity. As a result of experimental simulation studies, the highest hydraulic efficiencies of 40.87% and 39.5% are achieved in the case of the shaftless-grooveless and shafted-grooveless impeller, respectively. The maximum axial forces are obtained from the pump with the shaftless-grooveless impeller. Whereas radial forces, maximum values are calculated in the pump with the shaftless-outer groove impeller for all flow rates. Finally, the wall shear stresses, which are important for blood pump designs, are evaluated and the maximum value of 227 Pa is observed in the pump impeller with a shaftless-grooved.
Research Topics
Domains
Physical Sciences
Fields
Engineering
Subfields
Mechanical EngineeringBiomedical EngineeringMechanics of Materials
Specific Research Areas
Hydraulic and Pneumatic Systems
Mechanical Circulatory Support Devices
Cavitation Phenomena in Pumps
Refrigeration and Air Conditioning Technologies
Advanced Thermodynamic Systems and Engines
Sustainable Development Goals
3GOOD HEALTH AND WELL-BEING
3
Research Products
7AFFORDABLE AND CLEAN ENERGY
1
Research Products
Documents
19
Citations
608
h-index
9
Documents
19
Citations
529
Publication Collaboration
| Affiliation Name | Count |
|---|---|
| Konya Technical University | 14 |
| Selçuk University | 12 |
| Aksaray University | 2 |
| Necmettin Erbakan University | 2 |
| Bingöl University | 2 |
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Data obtained from OpenAlex
| Journal | Count |
|---|---|
| Advanced Structured Materials | 1 |
| Computer Methods and Programs in Biomedicine | 1 |
| International Journal of Artificial Organs | 1 |
| INTERNATIONAL JOURNAL OF ARTIFICIAL ORGANS | 1 |
| Journal of Artificial Organs | 1 |
Current Page: 1 / 3
Scholarly Output
19
Articles
12
Views / Downloads
65/81
Supervised MSc Theses
4
Supervised PhD Theses
1
WoS Citation Count
29
Scopus Citation Count
40
Patents
0
Projects
0
WoS Citations per Publication
1.53
Scopus Citations per Publication
2.11
Open Access Source
9
Supervised Theses
5
Scopus Quartile Distribution
Competency Cloud
