INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS Int. J. Numer. Meth. Fluids 2008; 56:1329–1336 Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/fld.1745 Numerical simulation of film cooling effectiveness on a flat plate Homayoon Kanani 1 , Mehrzad Shams 1, ∗, † , Reza Ebrahimi 1 and Taher Ahmadian 2, ‡ 1 K.N. Toosi University of Technology, Faculty of Mechanical Engineering, Pardis St., Mollasadra St., Vanak Sq., Tehran, Iran 2 Khuzestan Steel Company, 3rd Gate, 10 km Bandar Imam Khomeini Road, Ahwaz, Iran SUMMARY Numerical simulation has been conducted to study film cooling effectiveness on a flat plate. Three- dimensional geometry was generated and the effects of blowing ratio and geometrical shape were studied. A cylindrical round, simple angle (CYSA) and laterally diffused, simple angle (LDSA) hole with a streamwise angle of 30 ◦ and spanwise angle of 0 ◦ were used. Hole length to diameter ratio ( L / D = 4) is constant for all geometries. Also the diameter of film cooling hole for different cooling holes at the entrance surface ( D = 10 mm) is constant. The blowing ratio ranges from 0.5 to 1.67, and the mainstream Reynolds number based on the mainstream velocity and hole diameter ( Re D ) was 8563. Both local and lateral averaged values are presented. Results have a good correspondence with experimental data obtained by Yuen and Martinez-Botas (Int. J. Heat Mass Transfer 2003; 46:221–235). The simulation results show that cooling hole shape affects film cooling effectiveness significantly. The LDSA hole decreases the momentum of jet flow at the exit area of the hole and avoids lift-off phenomenon. Counter-rotating vortex formed downstream of the hole is weaker for the LDSA hole and secondary flow is not powerful enough to disturb the jet flow structure next to the wall. Also the results show that the LDSA hole has a better lateral coverage due to the diffused shape of the hole and has a higher effectiveness value in a wider region on the wall. Copyright 2008 John Wiley & Sons, Ltd. Received 19 May 2007; Revised 12 December 2007; Accepted 12 December 2007 KEY WORDS: film cooling; single hole; computational fluid dynamics; flat plate 1. INTRODUCTION Film cooling is commonly used to prevent thermal failure in turbine blades that could result from the operation in high temperature environment. Film cooling studies on a flat plate with cylindrical ∗ Correspondence to: Mehrzad Shams, K.N. Toosi University of Technology, Faculty of Mechanical Engineering, Pardis St., Mollasadra St., Vanak Sq., Tehran, Iran. † E-mail: shams@kntu.ac.ir ‡ Engineering Manager. Contract/grant sponsor: Khuzestan Steel Company Copyright 2008 John Wiley & Sons, Ltd.