1 American Institute of Aeronautics and Astronautics Effect of Radiation on Gas Turbine Combustor Liner Temperature with Conjugate Heat Transfer (CHT) Methodology Yucel Saygin 1 , Ozan Can Kocaman 1 and Sitki Uslu. 2 TOBB University of Economics and Technology, Ankara, 06560, TURKEY Design of a gas turbine combustor is a challenging process. It contains many stages including estimation of liner wall temperatures in order to determine the lifetime of the engine. Therefore, accurate prediction of the liner wall temperature is an essential part of the gas turbine combustor design. The liner is heated by convection and radiation of the combustion gases inside the flame tube and it is cooled by convection to the air in annulus and radiation to the outer casing. Many studies have been performed with Conjugate Heat Transfer (CHT) methodology neglecting the effect of radiation on the liner temperature due to its complexity and limited computational power sources. The Effect of radiative heat transfer on combustor liner temperature using CHT methodology is studied in the present work. Radiation from luminous flame which is caused by formation of soot particles in the flame is not accounted for and radiation from non-luminous flame due to combustion gases, CO 2 and H 2 O, and surface radiation is investigated. Effect of turbulent Schmidt/Prandtl number is also investigated in this paper. I. Introduction In order to calculate the distribution of wall temperatures, wall adjacent temperatures and wall heat transfer coefficients are required. However, it is difficult to obtain these parameters with experiments under high temperature and high pressure environment with a complicated geometry 1 . Therefore CFD analyses became a popular tool with developing Conjugated Heat Transfer (CHT) solver and turbulence models. Many researchers have performed CFD analyses including combustion, fluid flow and the heat transfer in the gas turbine combustors. 2-9 Liner wall temperatures can be computed with commercial Computational Fluid Dynamics (CFD) code Star- CCM+ by solving the 3D conduction heat transfer equation in the solid wall coupled with the solution of Navier Stokes and species transport equations in the fluid part. In the CHT computations, radiation from gases and surfaces of the combustor walls and convection in the surrounding fluid are counted for. This approach provides prediction of liner wall temperature which is becoming increasingly important phenomenon when it comes to designing a gas turbine combustor. For an efficient design of a combustor with less pollutant emissions, it is essential to predict the liner wall temperatures. 10 On the other hand, prediction of liner wall temperature provides to determine hot spots in the liner wall and the reliability of wall cooling technology of the design. In addition, one needs monitoring the temperatures to avoid high temperatures in liner walls which could cause failure in wall material and decreased engine life eventually. Comparison of CFD-CHT results with experimental measurements, e.g. thermal paint and thermocouple point measurements is of vital importance for the reliability of the predictions. 1 Graduate Student, Combustion Systems Laboratory, Mechanical Engineering, AIAA Student Member. 2 Assistant Professor, Combustion Systems Laboratory, Mechancial Engineering, AIAA Member.