Design-Optimization Approach to Multistage Axial Contra-Rotating Turbines
Air Turbo Rocket engines, suitable for high-speed propulsion, require compact turbomachinery. This paper presents the design of an innovative multi-stage turbine mounted at the hub of a counter-rotating fan. Hence, the turbine airfoils are required to deliver high torque at low peripheral speeds. The design methodology specifically developed for this fourteen-stage turbine relies on two successive optimization cycles. The first one is based on a through-flow 1D code. This optimization cycle explores a vast set of possible design solutions. In a second step, an optimization using a 3D high fidelity RANS defines the 3D airfoil geometry. In order to accelerate the entire design procedure, a special routine was developed to morph the 1D results into the required info for the 3D optimization. Both the 1D and 3D optimizations are based on differential evolution algorithm.