Exit temperature profile measurement and CFD comparisons on small scale turbojet combustor with air blast atomizer configuration

Small scale turbojet engines are used in miniature UAVs and target drones. Combustor design at this scale is a challenge due to reduced volume for atomization, mixing and subsequent combustion. Furthermore correct estimation for the engine lifetime is critical in the design phase. In terms of lifetime hot-section components are much more critical. Exit temperature profile, which is commonly quantified using radial temperature distribution factor or using overall temperature distribution factor, is critical for the lifetime determination of critical hot-section engine components such as the first stage inlet guide vane of the turbine. This study presents the viability of the CFD approach for combustor design in terms of comparisons with experimental results put a spotlight to the areas that should improve in order to develop better CFD methods and practices. Results indicate that significant variability might occur even with the slightest manifold design modification. Also injector-to-injector flow rate variability has an effect on the exit plane temperature distribution causing hot-spots. CFD predictions agree with experimental results within engineering accuracy. However, experimental verification is quite necessary to reach a final judgement on the combustor design.