Description: Advanced turbomachinery components play a critical role in launch vehicle and spacecraft liquid rocket propulsion systems. To achieve desired efficiencies, extremely tight tolerances are often imposed between inducer blades and shrouds or other system components which sets up strong interactions that influence both the aerodynamics and the structural performance of blades and vanes. These transient interactions, including rotor-stator interactions (RSI), can deform the blades and significantly impact the vibrational and acoustic characteristics of the engine, greatly reduce the efficiency, and even lead to blade or vane failure. Current production design tools for turbomachinery do not account for the coupled fluid-structure interaction (FSI) physics associated with these phenomena. This STTR effort will develop and deliver a multidisciplinary design tool for advanced turbomachinery components to account for FSI phenomena and enable more accurate modeling of systems and subscale demonstrators. CFDRC will supplement the NASA massively parallel Loci framework with highly accurate and efficient integrated FSI capabilities to enable better understanding of critical turbomachinery problems in liquid rocket propulsion systems that defy conventional predictions. Loci will be enhanced to enable constrained deformations in moving overset grid systems to support prediction of structural response and fluid-induced vibration in rotating components. Phase I will demonstrate improved modeling fidelity and provide great insight into FSI phenomena in turbomachinery, and Phase II will bring the complete predictive capabilities to production for detailed investigations into advanced turbomachinery for liquid rocket propulsion systems.

Benefits: The proposed development of a fully coupled fluid-structure interaction (FSI) tool provides a unique opportunity to optimize design, realize additional system efficiencies, reduce weight and/or cost, and increase part life in future generations of liquid rocket engine (LRE) designs. A fully-coupled FSI tool has a large number of other applications in the NASA launch vehicles propulsion systems including: (a) prediction of rocket launch-induced fluctuating pressure loads and structural response; (b) prediction of water suppression system interactions with ignition over pressure (IOP) accurate prediction of acoustic environment; (c) prediction of vehicle buffet during ascent, (d) fluid-thermal-structural coupling of rocket engine nozzles; (e) FSI in nuclear thermal rockets; (f) prediction of self-generated dynamics of fluid delivery pipes with deformable bellows; (g) liquid propellant tank breathing due to liquid interaction with the flexible tank shell; and (h) design of new generation POGO accumulators with bellows separating liquid and gas phases.

The developed FSI analysis tool will provide accurate high-fidelity aerothermoelastic analyses for dynamic loads for turbomachinery, inducer, delivery pipes, and valves. Aerospace engineers will be able to utilize the technology to analyze early designs thereby reducing the dependence on expensive wind tunnel/water tunnel and flight tests. Benefits will be achieved in final performance, and enhanced structural integrity, prolonged structural life, and improved safety of vehicles. Direct applications include analysis of dynamic loads problems for aerospace vehicles; e.g. buffet, flutter, buzz, and control reversal; and noise, vibrations, and buffet suppression of rotorcraft and commercial air vehicles. Other applications include vortex-blade/control surfaces interaction for rotorcraft and fixed wing aircraft, heat exchanger vibration, strumming of cables and offshore pipelines, galloping of towers and masts, and fatigue of panels.