Investigation of Velocity Ratio Difference between the Controlling Jets and the Main Jet in the Compound Triple Jets Arrangement to Modify the Film Cooling Effectiveness, Using the LES Approach

Document Type : Research Paper

Authors

Abstract

In this research, effects of blowing ratio (velocity ratio) difference between the controlling small jets and the main jet in the compound triple jets arrangement on the film cooling effectiveness and the flow hydrodynamics are investigated. This blowing ratio difference was selected such that the total mass flow rate of the cold flow becomes equal to that of the simple compound triple jets. The triple jets are inclined normally into the cross flow and the cooling jets to the hot cross flow temperature ratio and the jets Reynolds number are 0.5 and 4700, respectively. The numerical approach is based on the finite volume and the SIMPLE algorithm over a multi-block, staggered, structured and non-uniform grid arrangement was applied. The numerical simulations are performed for three controlling jets to main jet velocity ratios. The obtained results show that when the velocity ratio is higher than unity, the film cooling effectiveness increases, while it decreases when the velocity ratio is less than unity. Due to high complication of the flow (results from interaction of three jets with the cross flow) and time dependency of the introduced vortex structures, the large eddy simulation approach was used to investigated the flow more accurately.

Keywords

References

[1] Eckert, E.R.G, and Livingood, J.N.B., “Comparison of Convection, Transpiration and Film Cooling Methods with Air as Coolant," NASA Report 1182, 1954.
[2] Goldstein, R.J., Eckert, E.R.G., and Bogard, F., “Effect of Hole Geometry and Density on Three Dimensional Film Cooling”, Int. J. Heat and Mass Transfer, Vol. 17, pp. 595-607, 1973.
[3]Jubran, B., and Brown, A., “Film Cooling from Two Rows of Holes Inclined in the Streamwise and SpanwiseDirections,” ASME J. Eng. Gas Turbines Power, 107, pp. 84–91, 1985.
[4] Ligrani, P.M., Bishop, D.T., and Ciriello, S., "Heat Transfer, Adiabatic Effectiveness and Injection Distributions Downstream of a Single Row and Two Staggered Rows of Compound Angle Film Cooling Holes," ASME Journal Turbomachinery, Vol. 114, pp. 687-700, 1992.
[5] Leylek, J.H., and Walters, D.K., "A Systematic Computational Methodology Applied to Three Dimensional Film Cooling Flow Field," ASME Journal of Turbomachinery , Vol. 119, pp. 777-785, 1997.
[6] Reiss, H., Bölcs, A., "Aerodynamic Loss Measurements in a Linear Cascade with Film Cooling Injection," 15th Bi-annual Symposium on Measurement Techniques in Transonic and Supersonic Flow in Cascades and Turbomachines, University of Florence, 21-22 Sept, 2000.
[7] Acharya, S., Tyagi, M., and Hoda, A., "Flow and Heat Transfer Predictions for Film Cooling," Heat Transfer in Gas Turbine Systems, Annals Of The New York Academy Of Science 934, pp. 110–125,  2001.
[8] Reddy, D.R. and Zaman, K.B.M.Q., “Computational Study of Effect of Tabs on a Jet in a Cross Flow,” Computers & Fluids, pp. 712–723, 2006.
[9] Way, S.K., and Bogard, D.G., "High Resolution Film Cooling Effectiveness Measurements of Axial Holes Embedded in a Transverse Trench with Various Trench Configurations," ASME Journal of Turbomachinery, Vol. 129, 2007.
[10] Ramezanizadeh, M., Taeibi-Rahni, M., and Saidi, M.H., “Investigation of Density Ratio Effects on Normally Injected Cold Jets into a Hot Cross Flow,” Arch. App. Mech., pp. 835-847, 2006.
[11] رمضانی زاده، مهدی، “حل عددی پدیده خنک کاری لایه ای در یک جریان آشفته به روش شبیه­سازی گردابه­های بزرگ با استفاده از مدل­های زیرشبکه­ای مختلف، “پایان­نامه­ی دکترا، دانشگاه صنعتی شریف، تهران، ایران، 1386.
[12] Brandt, T.T., “Study of Large Eddy Simulation and Smagorinsky Model Using Explicit Filtering,” 36th AIAA Fluid Dynamics Conference and Exhibit, 5-8 June 2006.
[13] Sagaut, P., “Large Eddy Simulation for Incompressible Flows,” Springer, pp. 15-18, 2001.
[14] Javadi, Kh., Taeibi-Rahni, M., and Darbandi, M., “Jet-into-Crossflow Boundary-Layer Control: Innovation in Gas Turbine Cooling,” AIAA Journal, Vol. 45, No. 12, pp. 2910-2925, 2007.
[15] Ajersch, P., Zhou, J.M., Ketler, S., Salcudean, M., and Gartshore, I.S., “Multiple Jets in a Crossflow Detailed Measurements and Numerical Simulations,” ASME, 95-GT-9, pp. 1-16. 1995.
[16] فرهادی­آذر، روزبه، "شبیه­سازی خنک­کاری لایه­ای جت­های ترکیبی سه­گانه با استفاده از روش ال.ای.اس"پایان­نامه­ی کارشناسی ارشد، دانشگاه صنعتی شریف، تهران، ایران، 1388.

Files

Share

How to cite

Statistics