Yumurta Kesitli Atıksu Borularının Akış Performansının Star CCM+ Hesaplamalı Akışkanlar Dinamiği Programı ile Doğrulanması

Öz

Yumurta kesitli boru hatlarının hidrolik değerlendirmelerinin dairesel kesitlere göre daha az olması sebebiyle akış performansları literatürde çok fazla bulunmamaktadır. Bu çalışmada “Experimental and Numerical Analysis of Egg-Shaped Sewer Pipes Flow Performance” adlı makaledeki deneysel ve HAD (Hesaplamalı akışkanlar dinamiği) (Ansys CFX) sonuçlarının akış performansları farklı bir yazılım ile karşılaştırılmıştır. Star CCM+, türbülanslı akış problemlerinin çözümünde kullanılan multidisipliner bir yazılım olup, doğruluğunun ortaya konması ve atıksu hidrolik analizlerinde kullanılmasının yaygınlaşması hedeflenmiştir. Deney seti, H:385 mm, R:110 mm boyutlarındaki boru hattı yumurta kesitli geometri olup, 11 m uzunluğunda %0,2 eğimlidir. SolidWorks ile deney düzeneği oluşturularak, Star CCM+ yazılımına aktarılmıştır. Yazılımda sınır koşulları, iki fazlı (su + hava) akış ve fizik şartları deneysel verilerinden yararlanılarak simüle edilmiştir. Farklı su yüksekliklerinde, h/H = 0,2, 0,3, 0,4 ve 0,5 olmak üzere işletme çalışması yapılmıştır. Belirlenen akış performans değerleri olan; deşarjlar, hız değerleri, reynolds sayıları, kayma gerilmeleri ve boru hattı orta kesit hız dağılımları deneysel ve Ansys CFX yazılımı ile karşılaştırılmıştır. Karşılaştırma sonuçlarına göre Star CCM+ yazılımında; h/H=0,20’de maksimum hızda %8,80, ortalama hız ile deşarjda %3,10 ve kayma gerilmesinde -%2,60’lık fark görülmüştür. h/H=0,30’da maksimum hızda -%3,40, ortalama hız ile deşarjda %7,40 ve kayma gerilmesinde %1,50’lik fark oluşmuştur. h/H=0,40’da maksimum hızda %5,00 fark, ortalama hız ile deşarjda %2,60 ve kayma gerilmesinde %2,50’lik fark meydana gelmiştir. h/H=0,50’de ise maksimum hızda %17,00 fark, ortalama hız ile deşarjda %2,60 fark ve kayma gerilmesinde %0,20’lik fark oluşmuştur. Bu değerlendirmelere göre, deneysel akış performans değerleri ile Star CCM+ sonuçları benzerlik göstermiştir. Böylece Star CCM+ programının akışkanların akış performans değerlendirmelerinde kullanılabileceği sonucuna varılmıştır.

Anahtar Kelimeler

• Hesaplamalı Akışkanlar Dinamiği
• Yumurta kesitli atıksu boruları
• Star CCM+
• Akış performansı.

Verification of the Flow Performance of Egg-Section Wastewater Pipes with Star CCM+ Computational Fluid Dynamics Program

Öz

Due to the fact that hydraulic evaluations of egg-shaped pipe sections are less common than those of circular sections, their flow performance is not widely documented in the literature. In this study, the experimental and CFD (Computational Fluid Dynamics) (Ansys CFX) results from the article titled “Experimental and Numerical Analysis of Egg-Shaped Sewer Pipes Flow Performance” were compared with flow performance using a different software. Star CCM+ is a multidisciplinary software used to solve turbulent flow problems, and the aim is to demonstrate its accuracy and promote its use in wastewater hydraulic analyses. The experimental setup consists of an egg-shaped pipe geometry with dimensions H: 385 mm and R: 110 mm, and a length of 11 m with a 0.2% slope. The experimental setup was created using SolidWorks and transferred to the Star CCM+ software. In the software, boundary conditions, two-phase (water + air) flow, and physical conditions were simulated using experimental data. Operational tests were conducted at different water levels, with h/H = 0.2, 0.3, 0.4, and 0.5. The determined flow performance values, including discharges, velocity values, Reynolds numbers, shear stresses, and pipe line mid-section velocity distributions, were compared with experimental data and Ansys CFX software. According to the comparison results, in the Star CCM+ software, at h/H = 0.20, there was an 8.80% difference in maximum velocity, a 3.10% difference in average velocity and discharge, and a -2.60% difference in shear stress. At h/H=0.30, there was a difference of -3.40% in maximum velocity, 7.40% in average velocity at discharge, and 1.50% in shear stress. At h/H=0.40, there was a difference of 5.00% in maximum velocity, 2.60% in average velocity at discharge, and 2.50% in shear stress. At h/H=0.50, there was a 17.00% difference at maximum speed, a 2.60% difference at average speed during discharge, and a 0.20% difference in shear stress. According to these evaluations, experimental flow performance values and Star CCM+ results were similar. Thus, it was concluded that the Star CCM+ program can be used for evaluating the flow performance of fluids.

Anahtar Kelimeler

• Computational Fluid Dynamics
• Egg section wastewater pipes
• Star CCM+
• Flow performance

Kaynakça

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