International Journal of Mechanical Engineering ISSN : 2277-7059 Volume 2 Issue 2 http://www.ijmejournal.com/ https://sites.google.com/site/journalijme/ 85 ANALYSIS OF THE EFFECT OF CHANGES IN FUEL INJECTOR POSITION ON GAS TURBINE COMBUSTION EFFICIENCY USING LARGE EDDY SIMULATION (LES) Shandy Kharisma Irianto 1 , Gunawan Nugroho 2 Department of Engineering Physics, Institut Teknologi Sepuluh Nopember Surabaya Indonesia 60111 Abstract. Researches on gas turbine have been widely performed, especially on combustion chamber with a non-premixed combustion process. In this work, the research ofthe combustion chamber has been performed using the LES method. The aim of this study is to analyze the combustion process with various fuel injector angles and fuel rate. The analyzed aspects are flow pattern, temperature distribution and species concentration on stoichiometry condition. The mixing process between fuel and air at the combustion zone is affected by the increase in injector angle which, 33.55 o (model 1) being the optimum injector angle to obtain the highest efficiency of 84.6%. It is noted that model 2 (injector 45 o ) has the lowest emission containing waste gases of CH 4 and CO, i.e. 0.75 and 0.089 times lower than those of model 1, respectively. However, the combustion efficiency of model 2 is lower than model 1, i.e. 82.7%. Keywords: Gas turbine combustor, Large Eddy Simulation (LES), Stoichiometry, Computational Fluid Dynamics. 1. I NTRODUCTION Gas turbine is a machine which is often encountered in aircraft and large scale power generation industry. On the aircraft, gas turbine is used as a main driving machine while on the power generation industry, gas turbine is used to drive turbine that been coupled with generator to produce the electrical power [1]. Gas turbine consists of three main components, they are compressor that is used to compress the combustion air, the combustor where combustion process occurs and the turbine where in the work is produced. Researches on gas turbine have been widely performed. The aims are for combustion efficiency and turbine blade temperature enhancement, combustion stabilization on lean mixture enhancement that can save the fuel. The design method of direct experimental needs high cost and time consuming. Therefore, many researches are performed with Computational Fluid Dynamics (CFD) simulation [2]. There are many methods in simulation using CFD. They are Direct Numerical Simulation (DNS), Reynolds or Favre Averaging of the Navier-Stokes Equations (RANS) and Large Eddy Simulations (LES) .The DNS and LES are able to give a better prediction in unsteady flow behaviour and give more detail results than RANS method [3]. LES method is often used in many previous researches because LES 1 shandy_tf07@ep.its.ac.id 2 gunawan@ep.its.ac.id, gunawanzz@yahoo.com