کاربرد مدل جبری غیرایزوتروپ آشفتگی در حل عددی خنک کاری لایه ای با جتهای سه گانه

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه آزاد اسلامی واحد تهران مرکزی

2 صنعتی شریف

چکیده

در این پژوهش، موضوع خنک کاری لایه ای در جتهای سه گانه مورد بررسی عددی قرار گرفته است. بدین منظور از مدل توربولانسی k-ω SST به همراه یک مدل جبری غیر ایزوتروپ آشفتگی بهره گرفته شده است. همچنین، جهت حل معادلات از یک شبکه جابجا شده و روش حجم محدود به همراه الگوریتم سیمپل استفاده گردیده و نتایج حاصله با نتایج عددی موجود اعتبار سنجی شده است. مطابق با نتایج بدست آمده، مدل جبری غیرایزوتروپ آشفتگی توانسته باعث بهبود نسبی مقادیر متوسط تمامی کمیتها در آشفتگی شود. همچنین، تعداد تکرارها جهت رسیدن به معیار همگرایی با بکارگیری این مدل کاهش یافته است. از طرف دیگر، این مدل باعث شده تا دقت محاسبه برخی کمیتهای آشفتگی نظیر انرژی جنبشی، کاهش یابد. به طور کلی، این مدل در جتهای تکی (معمول) عملکرد بهتری از جتهای سه گانه داشته است.

کلیدواژه‌ها

عنوان مقاله [English]

Application of an Algebraic Anisotropic Turbulence Model in Numerical Solution of Triple Jet Film Cooling

نویسندگان [English]

  • hesam jazirian 1
  • mohammad tayebi rahni 2
  • arman adamian 1
1 azad , markazi
2 sharif
چکیده [English]

The best way to increase turbine efficiency is increasing the temperature of the incoming air. On the other hand, film cooling is the most efficient tool. In this work triple jet film cooling has been numerically investigated. Cross sections of all jets were rectangular and were inclined normally into hot cross-flow. As far as turbulence modeling, k-ω/SST along with an algebraic non-isotropic turbulence model, as its modification, has been used. In addition, staggered grid and finite volume method with SIMPLE algorithm were implemented. The turbulence model used was shown to be able to predict mean quantities relatively close. Also, it had a much better convergence rate compared with standard k-ω SST model. On the other hand, this model did not predict some of the turbulent quantities (such as turbulent kinetic energy) close enough. Finally, it seems to work better in single-jet film cooling, compared to a triple jet one.

کلیدواژه‌ها [English]

  • Film Cooling
  • Triple Jet
  • Anisotropic Turbulence Model
  • RANS Equations
  • Turbulence Modeling

مراجع

  1. Ajersch, P., Zhou, J.M., Ketler, S., Salcudean, M., and Gartshore, I.S. “Multiple Jets in a Cross Flow Detailed Measurements and Numerical Simulations”, ASME Paper No. 95-GT-9, 1995.
  2. Mahjoob, S. and Taeibi-Rahni, M. “Computational Study of Parameters Affecting Turbulent Flat Plate Film Cooling”, ASME Paper, No. GT2004-53027, pp. 23-32, 2004.
  3. Ramezanizadeh, M., Saiedi, M.H., and Taeibi-Rahni, M. “Computational Simulation of Two-dimensional Turbulent Film Cooling, Using LES Approach and Considering Density Ratio Effects”, Mech. Aerospace Eng. J., Vol. 3, No. 1, pp. 91-103, 2007 (In Persian).
  4. Farhadi-Azar, R., Ramezanizadeh, M., Taeibi-Rahni, M. and Salimi, M. “Compound Triple Jets Film Cooling Improvements Via Velocity and Density Ratios: Large Eddy Simulation”, J. Fluids Eng. Vol. 133, No. 3, pp. 031202, 2011.
  5. Li, X., Ren, J., and Jiang, H. “Application of Algebraic Anisotropic Turbulence Model to Film Cooling Flows”, International Journal of Heat and Mass Transfer, Vol. 91, pp. 7-17, 2015.
  6. Salimi, M.R., Taeibi-Rahni, M., Ramezanizadeh, M., and Farhadi-Azar, R. “Film Cooling Effectiveness Enhancement Applying another Jet in the Upstream Neighbor of the Main Jet, Using LES Approach”, Journal of Applied Fluid Mechanics, Vol. 9, No. 1, pp. 33-42, 2016.
  7. Xie, G., Liu, X., and Yan. H. “Film Cooling Performance and Flow Characteristics of Internal Cooling Channels with Continuous/Truncated Ribs”, International Journal of Heat and Mass Transfer, Vol. 105, pp. 67-75, 2017.
  8. Hayes, S.A., Nix, A.C., Nestor. C.M., Billups, D.T. and Haught, S.M. “Experimental Investigation of the Influence of Freestream Turbulence on an Anti-Vortex Film Cooling Hole”, Experimental Thermal and Fluid Science, Vol. 81, pp. 314-326, 2017.
  9. Mazaheri, K., Kiani, K.C., and Karimi, M. “A Modified Turbulent Heat-Flux Model for Predicting Heat Transfer in Separating-Reattaching Flows and Film Cooling Applications”, Applied Thermal Engineering, Vol. 110, pp. 1609-1623, 2017.
  10. Tu, Z., Mao, J., and Han, X. “Numerical Study of Film Cooling over a Flat Plate with Anisotropic Thermal Conductivity”, Applied Thermal Engineering, Vol. 111, pp. 968-980, 2017.
  11. Javadi, Kh. “Computational Simulation of an Incompressible/ Compressible Turbulent Jet-into-crossflow-An Innovation in Film Cooling”, Ph.D Dissertation, Sharif University of Technology, Aerospace Eng. Depʼt., 2007 (In Persian).
  12. Menter, F.R. “Zonal Two-Equation k-ω Turbulence Model for Aerodynamic Flow”, AIAA J., Proc. Int. 24th Conf. Fluid Dynamic, Orlando, U.S.A, 1993.
  13. Menter, F.R. “Two-equation Eddy-Viscosity Turbulence Model for Engineering Applications”, AIAA Journal, Vol 32, No.8, pp.1598-1604, 1994.
  14. Daly, B.J. and Harlow, F.H. “Transport Equations in Turbulence”, Phys. Fluids, No. 13, pp. 2634-2649, 1970.
  15. Kamotani, Y. and Greber, I. “Experiments on a Turbulent Jet in a Cross Flow”, AIAA J., Vol 10, pp. 1425-1429, 1972.
  16. Fearn, R. and Weston, R. “Vortices Associated with a Jet in a Cross Flow” AIAA J., Vol. 12, pp. 1666-1671. 1974.
  17. Broadwell, J.E. and Breidenthal, R.E., “Structure and Mixing of a Transverse Jet in Incompressible Flow”, J. Fluid Mech. Vol. 148, pp.405-412, 1984

فایل ها

سابقه مقاله

  • تاریخ دریافت: 22 خرداد 1396
  • تاریخ بازنگری: 11 خرداد 1399
  • تاریخ پذیرش: 28 شهریور 1397
  • تاریخ انتشار: 01 آبان 1396

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