Bir Otobüs Modeli Etrafındaki Akış Yapısının CFD Yöntemi İle İncelenmesi ve Sürükleme Kuvvetinin Pasif Akış Kontrol Yöntemi İle İyileştirilmesi

Yıl 2018, Cilt: 21 Sayı: 4, 785 - 795, 01.12.2018

Cihan Bayındırlı , Mehmet Çelik Mehmet Demiralp

https://doi.org/10.2339/politeknik.403993

Cited By: 5

Öz

Bu çalışmada, 1/64 ölçekli bir otobüs
modelinin aerodinamik direnç katsayısı hesaplamalı akışkanlar dinamiği
(CFD) yöntemi ile tespit edilmiştir. Akış analizleri x yönünde 15 m/s, 20 m/s,
25 m/s ve 30 m/s serbest akış hızlarında 173000-346000 Reynolds sayısı
aralığında gerçekleştirilmiştir. Akış analizleri Fluent® programında yapılmıştır.
Otobüs modelinin aerodinamik direnç katsayısı ortalama 0.657 olarak tespit
edilmiş, toplam direncin basınç ve sürtünme kaynaklı dağılımı belirlenmiştir. Model
otobüs üzerinde basınç kaynaklı direnç oluşturan bölgeler akış görüntülemeleri
ile tespit edilmiştir.  Akış yapısını
iyileştirilmek ve basınç kaynaklı direnci azaltmak için üçgen kesitli akış kontrol
elemanı geliştirilmiştir. Akış kontrol elemanı 15 mm çapında eşkenar üçgen
şeklinde olup model otobüsün ön tampon üzerine konumlandırılmıştır. Model 1
otobüsün aerodinamik direnç katsayısı 0.623 olarak tespit edilmiştir.  Bu pasif akış kontrol yöntemi ile aerodinamik
direnç katsayısında ortalama % 5.27 iyileşme sağlanmıştır. Elde edilen bu
iyileşmenin yüksek taşıt hızlarında yakıt tüketimine etkisi yaklaşık %3’tür. Bu
orandaki bir aerodinamik iyileşmenin bir otobüste yıllık yakıt tüketimine
etkisi değerlendirilmiştir.   

Anahtar Kelimeler

Sürükleme kuvvet katsayısı, pasif akış kontrolü, akış kontrol elemanı, hesaplamalı akışkanlar dinamiği (HAD)

The Investigation Of Flow Characteristic Around A Bus Model By CFD Method And Improvement Of Drag Force By Passive Flow Control Method

Öz

In this study, aerodynamic drag coefficient of 1/64 scaled bus model was
determined by the Computational Fluid Dynamics (CFD) method. Flow analyzes were
performed at 15 m/s, 20 m/s, 25 m/s ve 30 m/s in x direction, between the range
of 173000-346000 Reynolds numbers. Flow analysis was made in Fluent® program. The
aerodynamic drag coefficient (C_D) of the bus model was determined as
0.657 on average, the distribution of total drag was determined as
pressure-friction based. After the flow visualization, the areas are detected where
forms aerodynamic drag on the model bus. A triangular section flow control
element has been developed to improve the flow structure and decrease the
pressure based drag. The flow control element is an equilateral triangle with a
diameter of 15 mm and positioned on the front bumper of the model bus. The
aerodynamic drag coefficient of model 1 bus was determined as 0.623. With this
passive flow control method, the aerodynamic drag coefficient improved by %5.27.
The effect of this improvement on fuel consumption is about 3 % at the high
vehicle speed. The effect of this aerodynamic improvement on the annual fuel
consumption of a bus has been evaluated.

Anahtar Kelimeler

The drag force coefficient, passive flow control, flow control part, Computational Fluid Dynamics (CFD)

Kaynakça

• [1] Wood R.M. and Bauer, S.X.S., “Simple and low cost aerodynamic drag reduction devices for tractor-trailer Trucks”, SAE Technical Paper, 01–3377: 1-18, (2003).
• [2] http://www.udhb.gov.tr/, İstatistiklerle Ulaştırma, Denizcilik ve Haberleşme Raporu, (2003-2011).
• [3] Modi, V.J., Hill, S.St. and Yokomimizo, T., ”Drag reduction of trucks through boundary-layer control”, Journal of Wind Engineering And Industrial Aerodynamics, 54/55: 583-594, (1995).
• [4] Demircioğlu, T.K., “Bir araç modelinin Aerodinamik Analizi ve Sonlu Elemanlar Yöntemi ile Simülasyonu”, Yüksek Lisans Tezi, Balıkesir Üniversitesi Fen Bilimleri Enstitüsü, Balıkesir, 54-98, (2007).
• [5] Perzon, S., Janson, J., and Höglin, L., ”On comparisons between CFD methods and wind tunnel tests on a bluff bod”, SAE Technical Paper Series, 01-0805, 1-11, (1999).
• [6] Perzon, S., and Davidson, L., “On transient modeling of the flow around vehicles using the Reynolds equation”, International Conference on Applied Computational Fluid Dynamics (ACFD) Beijing China, 720-727 (2000).
• [7] Lokhande, B., Sovani, S., and Khalighi, B. “Transient simulation of the flow field around a generic pickup truck”, SAE Technical Paper Series, 01-1313: 1- 19, (2003).
• [8] Krajnovic, S., and Davidson, L. “Influence of flor motions in wind tunnels on the aerodynamicsof road vehicles”, Journal of Wind Engineering and Industrial Aerodynamics, 93: 677-696 (2005).
• [9] Apisakkul, K.T., and Kittichaikarn, C. “Numerical analysis of flow over car spoiler”. The Ninth Annual National Symposium on Computational Science and Engineering Papers ANSCSE-9, Bangkok, Thailand (2005).
• [10] Fares, E. “Unsteady flow simulation of the Ahmed reference body using a lattice Boltzmann approach”, Computers & Fluids, 35: 8-9, (2006).
• [11] Desai M., Channiwala S. A., and Nagarsheth, H. J. Experimental and Computational Aerodynamic Investigations of a Car”, WSEAS Transactions on Fluid Mechanics 4(3): 359-366 (2008).
• [12] Cheli, F., Ripamonti, E., Sabbioni, E., and Tomasini, G. “Wind Tunnel Tests on Heavy Road Vehicles: Cross Wind Induced Load”, Journal of Wind Engineering And Industrial Aerodynamics, 99: 1011-1024, (2011).
• [13] Hu, Xu-xia., and Wong, E.T.T. “ A Numerical Study On Rear-spoiler Of Passenger Vehicl”. World Academy of Science, Engineering and Technology, 57: 636-641, (2011).
• [14] Marinos, M., and SpyrosG, V.,”Experimental investigation of the flow past passive vortex generators on an airfoil experiencing three-dimensional separation”, Journal of Wind Engineering And Industrial Aerodynamics, 142: 130–148, (2015).
• [15] Aktaf, A. , Omar Ashraf A., Asrar W.,” Passive drag reduction of square back road vehicles”, Journal of Wind Engineering And Industrial Aerodynamics, 134: 30–43, (2014).
• [16] Cui, W., Zhu, H., Xia, C., Yanga, Z., “Comparison of steady blowing and synthetic jets for aerodynamic drag reduction of a simplified vehicle”, Procedia Engineering, 126: 388 – 392, (2015).
• [17] Mohamed-Kassim, Z., and Filippone, A., “Fuel savings on a heavy vehicle via aerodynamic drag reduction”, Transportation Research Part D, 15: 275–284, (2010).
• [18] Barden, J., and Gerova, K., “An on-road investigation into the conditions experienced by a heavy goods vehicle operating within the United Kingdom”, Transportation Research Part D, 48: 284–297, (2016).
• [19] Gurlek, C., Sahin, B., and Ozkan, G.M., “PIV studies around a bus model”, Experimental Thermal and Fluid Science 38: 115–126, (2012).
• [20] Liu, X., Han, Y., Cai, C.S., Levitan, M., Nikitopoulos D., “Wind tunnel tests for mean wind loads on road vehicles”, Journal of Wind Engineering And Industrial Aerodynamics, 150: 15–21, (2016).
• [21] Ji-qiang, N., Dan, Z., Xi-feng, L., “Experimental research on the aerodynamic characteristics of a high-speed train under different turbulence conditions”, Experimental Thermal and Fluid Science, 80: 117–125, (2017).
• [22] Hassan S.M.R., Islam, T.,Ali, M., Islam, Md. Q., “Numerical Study on Aerodynamic Drag Reduction of Racing Cars”, Procedia Engineering, 90: 308 – 313, (2014).
• [23] Chilbule, C., Upadhyay, A., Mukkamala, Y., “Analyzing the profile modification of truck-trailer to prune the aerodynamic drag and its repercussion on fuel consumption”, Procedia Engineering, 97: 1208 – 1219, (2014).
• [24] Muthuvel, A., Murthi, M.K. Sachin, N.P, Vinay.M.K., Sakthi, S.,Selvakumar, E., “Aerodynamic Exterior Body Design of Bus”, International Journal of Scientific & Engineering Research, 4(7): 2453-2457, (2013).
• [25] Patil, C.N., Shashishekar, K.S., Balasubramanian, A.K., Subbaramaiah, S.V., “Aerodynamic Study and drag coefficient optimization of passenger vehicle”, International Journal of Engineering Research & Technology (IJERT), 1(7): 1-8, (2012).
• [26] Sarı, M,F., “Hafif Ticari Taşıtlarda Taşıt Ön Formuna Etkiyen Hava Direncinin Aerodinamik Analizi ve Yakıt Sarfiyatına Etkisi”, Yüksek Lisans Tezi, Osmangazi Üniversitesi Fen Bilimleri Enstitüsü, Eskişehir, 28-54, (2007).
• [27] Minoru, S., Katsuji, T., and Tatsuo, M., Aerodynamic characteristics of train/vehicles under cross winds. Journal of Journal of Wind Engineering And Industrial Aerodynamics, 91(1-2): 209-218, (2003).
• [28] Rohatgi, U.S., “Methods of Reducing Vehicle Aerodynamic Drag”, ASME Heat Transfer Conference Puesto Rico,USA, (2012).
• [29] Chowdhury, H., Moria,H., Abdulkadir, A., Khan I., Alam, F., and Watkins, S., “A Study on aerodynamic drag of a semi-trailer truck”, Procedia Engineering, 56: 201–205, (2013).
• [30] Akansu, Y. E., Özmert, M., Fırat E., “Akış Kontrol Çubuğu İle Kare Kesitli Bir Küt Cisim Etrafındaki Akış Kontrolünde Hücum Açısının Girdap Kopma Olayına Etkisi”, Isı Bilimi ve Tekniği Dergisi, 31(1): 109-120, (2011).
• [31] Solmaz, H., İcingur, Y., ”Drag Coefficient Determination Of A Bus Model Using Reynolds Number Independence”, International Journal of Automotive Engineering and Technologies, 4(3): 146-151, (2015).
• [32] Jonathan, M., , Erik, F., Gregory, R., Rajan, K., Kunihiko, T., Farrukh, A., Yoshihiro, Y., and Kei M,. “Drag reduction on a flat-back ground vehicle with active flow control”, Journal of Wind Engineering And Industrial Aerodynamics. 145: 292–303, (2015).
• [33] Çengel, Y.A., and Cimbala, J.M., “Akışkanlar Mekaniği Temelleri ve Uygulamaları” Güven Bilimsel Yayınları, İzmir, 562-599, (2008).
• [34] İnce, İ.T. “GTD Model İdari Hizmet Pikap Aracının Aerodinamik Analizi. Doktora Tezi”, Gazi Üniversitesi Fen bilimleri Enstitüsü, Ankara, 30-66, (2010).
• [35] Saygı. M.I., “Kare Model Etrafındaki Akışın Üfleme ve Emme İle Aktif Kontrolünde Hücum Açısının Ve Slot Kanal Konumunun Etkisinin Deneysel İncelenmesi”. Yüksek Lisans Tezi, Niğde Üniversitesi Fen Bilimleri Enstitüsü, Niğde, 88-95, ( 2008).
• [36] Bayındırlı, C., Akansu, Y.E., Salman, M.S., and Çolak, D., ”The Numerical Investigation of Aerodynamic Structures of Truck and Trailer Combinations”, International Journal of Automotive Engineering and Technologies, 4 (3): 139-145, (2015).