Çarpan Eş Eksenli Bir Hava Jetinde Debi Oranının Akış Karakteristikleri Üzerine Etkisinin Deneysel Olarak İncelenmesi

Yıl 2018, Cilt: 8 Sayı: 2, 239 - 248, 31.07.2018

Burak Markal

https://doi.org/10.17714/gumusfenbil.340800

Öz

Bu çalışmada, dairesel ve halkasal
eş eksenli akış pasajlarına sahip bir lüleden çıkarak dairesel bir plaka
üzerine çarpan jetin hidrodinamik karakteristikleri deneysel olarak
incelenmiştir. Deneyler üç farklı Reynolds sayısında (Re = 6688, 9364 ve 12039),
beş farklı debi oranında (Q* = 0, 0.2, 0.5, 0.8 ve 1.0) ve tek bir boyutsuz
lüle-plaka uzaklığında (H* = 0.8) gerçekleştirilmiştir. Belirtilen çalışma
parametreleri için boyutsuz basınç katsayısının (C_P) çarpma plakası
üzerinde merkez hattı boyunca dağılımı elde edilmiştir. İncelenen tüm Reynolds
sayılarında, Q* = 0, 0.2 ve 0.5 değerleri için durma noktası çarpma plakası
merkezinde oluşmakta ve ilgili noktaya ait basınç değerleri artan Q* ile
azalmaktadır. Q* = 0.8 ve 1.0 ise birbirine benzer davranış göstermekte olup,
bu şartlar altında çoklu durma noktaları oluşmaktadır.  

Anahtar Kelimeler

Basınç dağılımı, Debi oranı, Eş eksenli çarpan jet

Experimental Investigation of the Effect of Flow Rate Ratio on the Flow Characteristics in a Co-axial Impinging Air Jet

Öz

In this study, hydrodynamic characteristics of a
jet issuing from a nozzle with concentric circular and annular flow passages are
investigated experimentally. Experiments are conducted for different Reynolds
number (Re = 6688, 9364 and 12039) and flow rate ratio (Q* = 0, 0.2, 0.5, 0.8 and
1.0) at a constant dimensionless nozzle-to-plate distance (H* = 0.8). For the
relevant test parameters, the distribution of the dimensionless pressure
coefficient (C_P) through the centerline of the impingement plate is
obtained. For all the Reynolds numbers and the values of Q* = 0, 0.2 and 0.5,
the stagnation point formed at the center of the impingement plate, and the
relevant pressure values for this point decreases with increasing Q*. On the
contrary, Q* = 0.8 and 1.0 shows similar behaviors (for each other) in which
multiple stagnation points occur.           

Anahtar Kelimeler

Pressure distribution, Flow rate ratio, Co-axial impinging jet

Kaynakça

• Ahmed, Z.U., Al-Abdeli, Y.M. ve Guzzomi, F.G., 2016. Heat Transfer Characteristics of Swirling and Non-Swirling Impinging Turbulent Jets, International Journal of Heat and Mass Transfer, 102, 991–1003.
• Boualia, H., Hidouri, A., Chrigui, M. ve Sautet, J.C., 2017. Experimental Investigation of Central Jet Displacements on the Turbulence and Gas Dynamics of a Coaxial Burner, Applied Thermal Engineering, 116, 303-315.
• Celik, N. ve Eren, H., 2009. Heat Transfer Due to Impinging Co-Axial Jets and the Jets’ Fluid Flow Characteristics, Experimental Thermal and Fluid Science, 33, 715–727.
• Celik, N., 2011. Effects of the Surface Roughness on Heat Transfer of Perpendicularly Impinging Co-axial Jet, Heat Mass Transfer, 47, 1209–1217.
• Champagne, F.H. ve Wygnanski, I.J., 1971. A Experimental Investigation of Coaxial Turbulent Jets, International Journal of Heat and Mass Transfer, 14, 1445 – 1464.
• Dahm, W. J. A., Frieler, C.E. ve Tryggvason, G., 1992. Vortex Structure and Dynamics in the Near Field of a Coaxial Jet, Journal of Fluid Mechanics, 241, 371-402.
• Dhamanekar, A. ve Srinivasan K., 2017. Effect of Plate Inclination on The Noise of Impinging Jets, Applied Acoustics, 127, 354–364.
• Fan, J., Zhao, H. ve Cen, K., 1997. Particle Concentration and Size Measurements in Two-Phase Turbulent Coaxial Jets, Chemical Engineering Communications, 156, 115-129.
• Fang, C., Xu, J., Zhao, H., Li, W. ve Liu, H., 2016. Influences of the Wall Thickness on the Granular Dispersion in a Dense Gas–Solid Coaxial Jet, International Journal of Multiphase Flow, 81, 20–26.
• Fenot, M. ve Dorignac, E., 2016. Heat Transfer and Flow Structure of an Impinging Jet with Upstream Flow, International Journal of Thermal Sciences, 109, 386-400.
• Ko, N.W.M. ve Kwan, A.S.H., 1976. The Initial Region of Subsonic Coaxial Jets, Journal of Fluids Mechanics, 73, 305 – 332.
• Ko, N.W.M. ve Au, H., 1985. Coaxial Jets of Different Mean Velocity Ratios, Journal of Sound and Vibration, 100, 211-232.
• Kok, B., Varol, Y., Ayhan, H. ve Oztop, H.F., 2017. Experimental and Computational Analysis of Thermal Mixing Characteristics of a Coaxial Jet, Experimental Thermal and Fluid Science, 82, 276–286.
• Lu, H., Liu, H., Li, W. ve Xu, J., 2013. Factors Influencing the Characterization of Bubbles Produced by Coaxial Gas–Particle Jet Flow, Fuel, 108, 723–730.
• Mahmud, T., Truelove, J.S. ve Wall, T.F., 1987. Flow Characteristics of Swirling Coaxial Jets From Divergent Nozzles, Journal of Fluids Engineering, 109, 275-282.
• Mergheni, M. A., Boushaki, T., Sautet, J.C., Godard, G., Ticha, H.B. ve Nasrallah, S.B., 2008. Effects of Different Mean Velocity Ratios on Dynamics Characteristics of a Coaxial Jet, Thermal Science, 12 49-58.
• Mergheni, M.A., Riahi, Z., Sautet, J.C. ve Nasrallah, S.B., 2017. Swirl Effects on Dynamics Characteristics of A Coaxial Jet, Thermal Science, 21, 2543-2552.
• Muzychka, Y.S. ve Yovanovich, M.M., 2004. Laminar Forced Convection Heat Transfer in the Combined Entry Region of Non-Circular Ducts, Journal of Heat Transfer, 126, 54-61.
• Muzychka, Y.S., 2013. Generalized Models for Laminar Developing Flows in Heat Sinks and Heat Exchangers, Heat Transfer Engineering, 34, 2-3, 178-191.
• New, T.H. ve Tsioli, E., 2014. Effects of Area-Ratio on the Near-Field Flow Characteristics and Deflection of Circular Inclined Coaxial Jets, Experimental Thermal and Fluid Science, 54, 225–236.
• Nuntadusit, C., Wae-hayee, M., Bunyajitradulya, A. ve Eiamsa-ard, S., 2012. Visualization of Flow and Heat Transfer Characteristics for Swirling Impinging Jet, International Communications in Heat and Mass Transfer, 39, 640–648.
• Özmen, Y., İpek, G., 2015, Düz Bir Yüzeye Çarpan Slot Hava Jeti Dizisinde Basınç Dağılımlarının Deneysel İncelenmesi, ULIBTK’15 20. Ulusal Isı Bilimi ve Tekniği Kongresi, Eylül 2015, Balıkesir, Türkiye, s.1193-1201.
• Ozmen, Y., 2011. Confined Impinging Twin Air Jets at High Reynolds Numbers, Experimental Thermal and Fluid Science, 35, 355–363.
• Oztekin, E., Aydin, O. ve Avci, M., 2012. Hydrodynamics of a Turbulent Slot Jet Flow Impinging On a Concave Surface, International Communications in Heat and Mass Transfer, 39, 1631–1638.
• Rehab, H., Villermaux, E. ve Hopfinger, E.J., 1997, Flow Regimes of Large-Velocity-Ratio Coaxial Jets, Journal of Fluid Mechanics, 345, 357-381.
• Rim, B. K., Saïd, N.M., Bournot, H. ve Palec, G.L., 2016. Effect of Nozzle‑to‑Plate Spacing on the Development of a Plane Jet Impinging on a Heated Plate, Heat Mass Transfer, 53, 1305-1314.
• Schumaker, S.A. ve Driscoll, J.F., 2009. Coaxial Turbulent Jet Flames: Scaling Relations for Measured Stoichiometric Mixing Lengths, Proceedings of the Combustion Institute, 32, 1655–1662.
• Yu, Y.Z., Zhang, J.Z. ve Xu, H.S., 2014. Convective Heat Transfer by a Row of Confined Air Jets From Round Holes Equipped with Triangular Tabs, International Journal of Heat and Mass Transfer, 72, 222-233.