Simulations of Ducted and Coaxial Rotors for Air Taxi Operations

Diaz, Patricia Ventura; Rubio, Rafael Caracuel; Yoon, Seokkwan

doi:10.2514/6.2019-2825

Cited by 9 publications

(2 citation statements)

References 8 publications

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“…Diaz et al [50, 51] simulated ducts’ effects on coaxial rotors and analysed the aerodynamics and performance of the side-by-side air taxi. Diaz and Yoon [52] carried out a high-fidelity CFD simulation for analyzing NASA’s quadrotor urban air-taxi concept.…”

Section: Uavs Applicationsmentioning

confidence: 99%

Applications and classifications of unmanned aerial vehicles: A literature review with focus on multi-rotors

2022

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During the past two decades, with the advancement of avionics, control systems, design, product methods, and communication systems, UAVs have gained more interest from both civil and military customers. Hence, more researchers have dedicated their time to developing new applications for drones and improving their performance. In this study, a literature review on drone applications is conducted. It is explained that they can be more effective and beneficial when merged with preexisting systems, and thus making a system of systems. Further, we have classified UAV applications more comprehensively. This classification can be very useful for providing insights when designing new UAVs. Finally, previous works are discussed thoroughly and diagrams are developed to show the research focus in this field. These statistical diagrams can also be used as a gap analysis tool.

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Section: Uavs Applicationsmentioning

confidence: 99%

Applications and classifications of unmanned aerial vehicles: A literature review with focus on multi-rotors

2022

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“…Coaxial rotor systems are finding increased use and interest from several different sectors of the rotorcraft market due to their condensed packaging, higher redundancy in multirotor systems, and benefits in high-speed forward flight. Whether it be full-sized helicopters such as the Sikorsky XH-59A, X2, and S-97 [1][2][3], new light helicopter designs and urban air mobility applications for commercial transportation [4][5][6][7], or smaller unmanned systems that fly both here on Earth and explore other worlds [8,9], this configuration is continually seeing more use. The increasing demand for coaxial rotors comes along with an increasing need to understand how they operate so we can improve their efficiency and performance.…”

Section: Introductionmentioning

confidence: 99%

Rotor Performance Predictions for Urban Air Mobility: Single vs. Coaxial Rigid Rotors

Cornelius,

Schmitz,

Palacios

et al. 2024

Aerospace

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This work details the development and validation of a methodology for high-resolution rotor models used in hybrid Blade Element Momentum Theory Unsteady Reynolds Averaged Navier–Stokes (BEMT-URANS) CFD. The methodology is shown to accurately predict single and coaxial rotor performance in a fraction of the time required by conventional CFD methods. The methodology has three key features: (1) a high-resolution BEMT rotor model enabling large reductions in grid size, (2) a discretized set of momentum sources to interface between the BEMT rotor model and the structured URANS flow solver, and (3) leveraging of the first two features to enable highly parallelized GPU-accelerated multirotor CFD simulations. The hybrid approach retains high-fidelity rotor inflow, wake propagation, and rotor–rotor interactional effects at a several orders of magnitude lower computational cost compared to conventional blade-resolved CFD while retaining high accuracy on steady rotor performance metrics. Rotor performance predictions of thrust and torque for both single and coaxial rotor configurations are compared to test the data that the authors obtained at the NASA Langley 14- by 22-ft. Subsonic Tunnel Facility. Simulations were run with both fully turbulent and free-transition airfoil performance tables to quantify the associated uncertainty. Single rotor thrust and torque were predicted on average within 4%. Coaxial thrust and power were predicted within an average of 5%. A vortex ring state (VRS) shielding phenomenon for coaxial rotor systems is also presented and discussed. The results support that this hybrid BEMT-URANS CFD methodology can be highly parallelized on GPU machines to obtain accurate rotor performance predictions across the full spectrum of possible UAM flight conditions in a fraction of the time required by conventional higher-fidelity methods. This strategy can be used to rapidly create look-up tables with hundreds to thousands of flight conditions using a three-dimensional multirotor CFD for UAM.

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Modified Lifting Line Method Based on Vortex Rings and Its Application on Lift Fan Design

WANG

Wang

et al. 2022

Trans. Japan Soc. Aero. S Sci.

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The image vortex model is widely used in lifting line method to predict the flow induced by the shroud and hub surface in ducted fan, but it does not perform well in lift fan design due to the zero far field inflow. In this paper the theoretical defects and numerical error propagation characteristic of the image vortex model in simulating duct surface are studied. Then the vortex rings correction based on image vortex model is verified and applied in lifting line method. In order to test the improved method, a 150 mm diameter lift fan is designed by the modified lifting line method, after that, analyzed by the modified lifting line itself and RANS solver respectively. The results show that the contribution of the vortex rings at the rotor accounts for 50% of the total induced velocity, and it accounts for 35% at the stator, which verifies the necessity of the vortex rings correction. The performance of the rotor and stator geometry is consistent with the design expectation, the efficiency is up to 90.97% by numerical simulation and 88.32% by experimental measurement, which confirms the reliability of the modified lifting line method developed in this paper especially on lift fan design.

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Simulations of Ducted and Coaxial Rotors for Air Taxi Operations

Cited by 9 publications

References 8 publications

Applications and classifications of unmanned aerial vehicles: A literature review with focus on multi-rotors

Applications and classifications of unmanned aerial vehicles: A literature review with focus on multi-rotors

Rotor Performance Predictions for Urban Air Mobility: Single vs. Coaxial Rigid Rotors

Modified Lifting Line Method Based on Vortex Rings and Its Application on Lift Fan Design

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