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Öğe The Effect of Balance Holes to Centrifugal Pump Performance(AMER INST PHYSICS, 2017) Babayiğit, Osman; Özgören, Muammer; Aksoy, Muharrem Hilmi; Kocaaslan, OsmanThe aim of this study is to analyze of a centrifugal pump with and without balance holes by using ANSYSFluent software. The pump used in the study is a commercial centrifugal pump consisting of two stages that is a model of Sempa Pump Company. Firstly, models of impeller, diffuser, suction and discharge sections of the centrifugal pump were separately drawn using Ansys and Solidworks software. Later, grid structures were generated on the flow volume of the pump. Turbulent flow volume was numerically solved by realizable k-. turbulence model. The flow analyses were focused on the centrifugal pump performance and the flow characteristics under different operational conditions with/ without balance holes. Distributions of flow characteristics such as velocity and pressure distributions in the flow volume were also determined, numerically. The results of Computational Fluid Dynamics (CFD) with/without balance holes for the pump head and hydraulic efficiency on the design flow rate of 80 m(3)/h were found to be 81.5/91.3 m and 51.9/65.3%, respectively.Öğe Effect of Bullet Velocity on Target Ballistics(Selçuk Üniversitesi, 2024) Akbaş, Kemal Furkan; Neşeli, Süleyman; Kocaaslan, OsmanThis study investigates the effect of the distance-dependent velocity of the bullet on the target. Inthis study, a 5.56x45 mm NATO bullet is used. The target plate is made of AISI 1020 withdimensions of 75x80x3 mm. The study is conducted numerically using the LS-Dyna modulewithin ANSYS Workbench. Analyses are performed for distances of 200, 250, 300, and 350meters, and as a result of these analyses, the stresses, velocity, and displacements of the bullet areanalyzed for both perforation and non-perforation of the target plate. When the results obtainedwithout working are examined, in the shot made from 200 meters, the maximum stress on thetarget plate is between 400-450 MPa, displacement is 35 mm, and the minimum velocity of thebullet after hitting the target plate is between 200-250 m/s. In the shot made from 350 meters, themaximum stress on the target plate is between 300-350 MPa, displacement is 10.5 mm, and theminimum velocity of the bullet after hitting the target plate is between 0-50 m/s. According tothese results, as the distance between the bullet and the target plate increases, the stress on thetarget plate has decreased by approximately 25%, displacement by 70%, and the velocity of thebullet by 80%.Öğe Experimental and CFD investigation of a multistage centrifugal pump including leakages and balance holes(DESALINATION PUBL, 2017) Babayigit, Osman; Ozgoren, Muammer; Aksoy, Muharrem Hilmi; Kocaaslan, OsmanThe aim of this study is to analyze numerically a multistage pump with some new approaches and compare the results with experimental data. A centrifugal pump, consisting of six backward curved blades, ten vane diffusers and two stages, was used. First, models of an impeller, a diffuser, suction and discharge sections of the centrifugal pump were separately designed by empirical equations. The flow volume of the pump was numerically solved by different turbulence models. Thus, the most accurate results in comparison with experimental data were obtained for the realizable k-epsilon turbulence model. For the purposes of this study, the effect of balance holes and leakages (clearances) on the performance was scrutinized. In most studies, it is not taken into consideration in computational fluid dynamics (CFD) analyses due to the difficulty of meshing these regions. The experimental studies were performed at a computer controlled pump test rig that was established according to the standard TS EN ISO 9906. The results of CFD/experimental analyses for the pump head, hydraulic efficiency and hydraulic power on the design point, having the flow rate of 80 m(3)/h and the revolution of 2,975 rpm, were found to be 81.47/80.70 m, 51.98%/51.42% and 17.94/17.77 kW, respectively. The obtained CFD and experimental results were found to be close agreement for the design flow rate as well as for all tested flow rates. Other characteristics of the pump such as velocity, static pressure, streamline patterns and turbulence kinetic energy were also investigated. In addition, the leakages and balance holes have significantly affected the pump characteristics, which must be considered in CFD analyses in order to find more precise results for true-to-life simulations.Öğe Experimental and Numerical Investigation of Coating Effect on Pump Impeller and Volute(ISFAHAN UNIV TECHNOLOGY, 2016) Kocaaslan, Osman; Özgören, Muammer; Aksoy, Muharrem Hilmi; Babayiğit, OsmanIn this study, an impeller and volute of a centrifugal pump were designed and numerically analyzed in order to improve the pump efficiency. Before design, experimental and theoretical studies were performed on a centrifugal water pump taken as Model Pump (MP). Design parameters were taken as 100 m(3)/h for volume flow rate, 18m for head and 1480 rpm for rotating speed. After the inspection of the flow field in the MP, some geometrical modifications such as impeller inlet and outlet diameters, blade inlet and exit angles, blade wrap angle, blade thickness, blade inletand exit widthswere realized to design a new pump. Numerical analyses were performed for 8 different volume flow rates overlapping with experimental operation points by Ansys-Fluent Software. In numerical studies, k-epsilon turbulence model and standard wall function were utilized. The experimental and computational results were compared with the model pump. According to the analysis results at design flow rate, hydraulic torque value is decreased from 56.62 Nm to 51.05 Nm, while hydraulic efficiency is increased from 55.98% to 63.09%. In addition, in order to see the roughness effect and increase the pump efficiency, the wetted surfaces of the impeller and volute were coated with a polyurethane dye material. Later, performance curves of the coated and uncoated pumps were experimentally obtained which showed that the shaft power of the pump for the coated case was decreased around 10% and the hydraulic efficiency of the pump was increased approximately 18%. According to the economic analysis by basic payback period of the polyurethane coating is less than one year and the internal income ratio for ten-year life-cycle period is around %114.Öğe Numerical identification of blade exit angle effect on the performance for a multistage centrifugal pump impeller(E D P SCIENCES, 2015) Babayigit, Osman; Kocaaslan, Osman; Aksoy, Muharrem Hilmi; Guleren, Kursad Melih; Ozgoren, MuammerNowadays, single and multistage centrifugal pumps are widely used in industrial and mining enterprises. One of the most important components of a centrifugal pump is the impeller. The performance characteristics are related to the pump comprising the head and the overall efficiency rely a great deal on the impeller geometry. In this work, effects of blade exit angle change on hydraulic efficiency of a multi stage pump impeller are investigated via Ansys-Fluent computational fluid dynamics software for constant width impeller entrance and exit gates, blade numbers and blade thickness. Firstly, the flow volume of a centrifugal pump impeller is generated and then mesh structure is formed for the full impeller flow volume. Secondly, rotational periodic flow model are adopted in order to examine the effect of periodic flow assumption on the performance predictions. Corresponding to the available experimental data, inlet mass flow rate, outlet static pressure and rotation of impeller are taken as 0.02m(3)s(-1), 450 kPa and 2950 rpm, respectively for the water fluid. No slip boundary condition is exposed to all solid of surface in the flow volume. The continuity and Navier-Stokes equations with the k-epsilon turbulence model and the standard wall functions are used. During the study, numerical analyses are conducted for the blade exit angle values of 18 degrees, 20 degrees, 25 degrees, 30 degrees and 35 degrees. In consequence of the performed analyses, it is determined that hydraulic efficiency of the pump impeller value is changed between 81.0-84.6%. The most convenient blade exit angle that yields 84.6% hydraulic efficiency at is 18 degrees. The obtained results show that the blade exit angle range has an impact on the centrifugal pump performance describing the pump head and the hydraulic efficiency.Öğe Numerical Investigation of the Effect of Number of Blades on Centrifugal Pump Performance(AMER INST PHYSICS, 2017) Kocaaslan, Osman; Özgören, Muammer; Babayiğit, Osman; Aksoy, Muharrem HilmiIn this study, the flow structure in a centrifugal pump was numerically investigated for the different blade numbers in the impeller between 5 and 9. The pump used in the study is a single-stage horizontal shafted centrifugal pump. The original pump impeller was designed as 7 blades for the parameters of flow rate Q=100 m(3)/h, head Hm=180 kPa and revolution n=1480 rpm. First, models of impellers with the different blade numbers between 5 and 9 and the volute section of the centrifugal pump were separately drawn using Solidworks software. Later, grid structures were generated on the flow volume of the pump. Last, the flow analyses were performed and the flow characteristics under different operational conditions were determined numerically. In the numerical analyses, k-e turbulence model and standard wall functions were used to solve turbulent flow. Balance holes and surface roughness, which adversely affect the hydraulic efficiency of pumps, were also considered. The obtained results of the analyses show that the hydraulic torque and head values have increased with the application of higher number of the impeller blades. For the impellers with 5 and 9 blades on the design flow rate of 100 m(3)/h (Q/Qd=1), the hydraulic torque and head were found 49/59.1 Nm and 153.1/184.4 kPa, respectively. Subsequently the hydraulic efficiencies of each pump were calculated. As a result, the highest hydraulic efficiency on the design flow rate was calculated as 54.16% for the pump impeller having 8 blades.Öğe Verim iyileştirilmesi için optimize edilen ve poliüretan kaplama yapılan pompa çarkının sayısal ve deneysel analizi(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2015-02-27) Kocaaslan, Osman; Özgören, MuammerBu tez çalışmasında Sempa Ltd.Şti firmasının üretiminde yer alan yatay milli tek kademeli bir santrifüj pompanın verim iyileştirmesi amaçlı yapılan deneysel ve sayısal araştırma sonuçları karşılaştırılmıştır. Üretilmekte olan bu santrifüj pompanın verimini iyileştirmek için salyangoz ve çarkında geometrik olarak değişimler yapılmış ve hidrolik verimde gerçekleşebilecek iyileşmeler sayısal olarak tespit edilmiştir. Yapılan analizler sonucunda mevcut üretilen pompanın çalışma noktası olarak önerilen 100m^3⁄h hacimsel debide hidrolik tork değeri 55.44 Nm 'den 49.54 Nm 'ye düşmüştür. Bu sonuca bağlı olarak tasarlanan santrifüj pompa ile mevcut pompaya göre mil gücünde %10.71 mertebesinde enerji tasarrufunun yapılabileceğini göstermektedir. Ayrıca aynı sınır şartları koşulları ile yapılan sayısal analizlerde tasarlanan santrifüj pompada mevcut pompaya göre %14 oranında hidrolik verim artışı sağlanmıştır. Bilim Sanayi Teknoloji Bakanlığı'nın 01076 STZ 11-2 nolu projesinin bir bölümü olarak gerçekleştirilen bu tez çalışmasında yüzey pürüzlülüğünün santrifüj pompa verimi üzerine etkisi de incelenmiştir. Hesaplamalı Akışkanlar Dinamiği (HAD) ile 100m^3⁄h çalışma noktasında mevcut pompa çarkının ve salyangozunun sıvı akışkan ile temas eden yüzeylerine 0,0.1,0.3,0.5 ve 0.7 mm pürüzlülük yükseklikleri tanımlanarak sayısal analizler yapılmıştır. Yüzey pürüzlük yüksekliğinin artması ile hidrolik verim değerinin % 68'den % 53'e kadar düştüğü gözlemlenmiştir. Pompalarda kullanım esnasında aşınma ve kavitasyon ile çark yüzeylerinde oluşan deformasyonları önlemek amacıyla pompa çark ve salyangozunun sıvı akışkan ile temas eden yüzeyleri poliüretan malzeme ile kaplanmış ve yapılan kaplama işlemi ile santrifüj pompa veriminde meydana gelen değişimler incelenmiştir. Kaplamalı ve kaplamasız mevcut pompanın deneysel sonuçları incelendiğinde mil gücü değerlerinde %10 oranında azalmanın meydana geldiği hidrolik veriminde ise %25 oranında artış sağladığı gözlemlenmiştir. Yapılan ekonomik analiz sonucu poliüretan kaplama işlemi için yapılan yatırım 1 yıldan daha az sürede kendini geri ödediği ve pompa dikkate alınan 10 yıllık ömrü süresince yapılan kabuller çerçevesinde % 114 oranında kar getirebileceği görülmüştür. Poliüretan kaplama ile santrifüj pompa hidrolik veriminin arttırılmasının yanı sıra santrifüj pompa kullanım ömrünü de arttırıyor olması önemli bir avantaj olarak sunulabilecektir.
