In this Master thesis, the prediction of the aerodynamic performance on a low pressure turbine outlet guide vane is investigated. The standard approach at many aerospace companies to predict aerodynamic performance of gas turbine components like the guide vane is to use fully turbulent models in CFD analyses. However, recent tests show that the boundary layer on the guide vane often is initially laminar before transitioning into turbulent. Transition may occur through a process with natural instability, through bypass processes or through laminar separation. The transition mechanism depends, among other things, on the Reynolds number of the flow, the pressure gradient and the freestream turbulence intensity level.The main focus of this Master thesis has been to investigate the aerodynamic performance parameters like flow separation and pressure loss (both 2D and 3D loss) by applying three different transition models in CFD. The CFD predictions were further compared to test data from the test rig at Chalmers University of Technology. In order to study the impact of the mesh resolution on the results, two different meshes were also used. It was found that the transition models studied in this Master thesis show good agreement with test data in terms of vane static pressure loadings, wake pressure profiles, 2D pressure losses and also predicts laminar to turbulent transition by a laminar separation, like the test data shows. It was also found that the differences in mesh resolution studied here do not affect the results much, in terms of pressure loss predictions. A low-resolution mesh might need refinement if there are convergence issues, however.