Optimization of Combustion Chamber Length for Afterburner

ABSTRACT

Military jet aircrafts employ afterburners where the increase in thrust is more essential than specific fuel consumption. The experimental results are only available for the afterburner model with different combustion chamber lengths and no one ever has attempted to investigate the same using computational analysis. Hence, four full-scaled afterburners; with combustion chamber lengths of 3 feet, 4 feet, 5 feet and 6.5 feet; were modeled in SolidWorks®. The main components of diffuser, fuel manifolds, V-gutter, casing and liner with screech holes were included in each model for computational evaluation. Each 60o sector of these full-scaled afterburner models were imported separately into ANSYS® Fluent, for carrying out the steady state computational analysis using SIMPLE algorithm and realizable k-ε model and Kerosene (C12H23) as fuel with virtual fuel injectors. The analysis was carried out using Energy equation with Discrete Phase model. Multiple chemical reactions were solved with species transport selecting Finite Rate/ Eddy Dissipation model for combustion. The obtained CFD results were presented for all the four models for comparison. It was found that the afterburner model with combustion chamber length of five feet is the best suitable for production of maximum thrust which is matching with the already published experimental results.