Analysis of coupled thrust characteristics of multi-vectored propellers for high-altitude airships

High-altitude airships require large-diameter, low-speed propellers, due to the low air density at operating altitude of 20 km. A quantitative analysis of the thrust characteristics of onboard multi-vectored propellers is critical for the overall design and flight control of airships. This study employs the Fluent software to simulate the aerodynamic characteristics of multi-vectored propellers mounted on the airship, using the Multiple Reference Frame and Sliding Mesh (MRF–SM) techniques. A unified thrust model is developed using a multi-stage modeling approach combined with numerical simulation data. First, the model improves the accuracy of single propeller thrust prediction for the high-altitude propeller by compensating a quadratic term of the freestream velocity, building on conventional wind tunnel–based empirical formulas. In addition, the hull–propeller coupling effect is considered, and a correction term is added to model the thrust of the front vectored propeller. Finally, wake interference at small vectoring angles is addressed by introducing a propeller–propeller coupling correction term to construct the rear vectored propeller thrust model. Comparison with numerical results confirms that the unified model provides reliable predictions suitable for practical implementation, while also facilitating a sensitivity analysis of the thrust model with respect to physical variables, which demonstrates its potential to support control design for airships with multi-vectored propellers.