Optimal design and experiment of propellers for high altitude airship

Abstract

The multi-objective optimization design method and experimental validation of the propeller for high altitude airships are presented in this paper. The method of predicting the propeller's aerodynamic characteristics is based on the vortex theory. The non-dominated sorting genetic algorithm II is introduced and applied to solve the optimization problem. Then the optimization model which aims to design an efficient and lightweight propeller for high altitude airships is established based on the conditions of high altitude airships propulsion system. In addition, the effects of various design variables including pitch angle, chord length, diameter, rotational speed, and the number of blades on high altitude propeller performance are presented and discussed in a gradual manner. The optimization results indicate that the desirable tradeoff between the efficiency and weight of high altitude propeller is associated with the absorbed power, structural strength, and even the manufacturing and installation conditions. In order to evaluate the mathematical model and performance of the optimized propeller, wind tunnel experiments of scaled model on the basis of scaling laws and the full-scale propeller test using mobile testing system were carried out. It is shown that results obtained from the experiments agree well with those of the numerical calculation, which verifies that the designed propeller can satisfy the requirements of the high altitude airships' propulsion system.

Optimal Propeller design for future HALE UAV

“…Furthermore, reliable operation of the designed propeller in certain, specified, even unconventional working regimes also becomes attainable. Some examples of the research of high altitude propellers can be found in [9][10][11].…”

“…The work presented in [9] uses a single airfoil (constant function) and 4th order distributions of both chord and pitch. Similarly, [10] employs four predefined airfoils together with 3 rd order functions for c(r) and θ(r). This research describes a possible approach to the optimization of all three relevant blade features without the use of any constant or predefined values.…”

Estudio del sistema motopropulsivo para Pseudo-satélites = Design of the propulsion system for High Altitude Pseudo-Satellites

“…Una vez establecido el modelo, las siguientes dos cuestiones relevantes son qué es lo que se va a optimizar del diseño, y qué método se va a utilizar para conseguir esta optimización. Debido al aumento de la disponibilidad de los recursos computacionales, en losúltimos años han surgido diversos trabajos en los que la optimización se lleva a cabo usando machine learning e inteligencia artificial (e.g Jiao et al [59])). Sin embargo, ese tipo de métodos tienen como inconveniente la dificultad en hallar significado físico en la solución.…”

“…Jiao et al [59] usó como método de optimización un algoritmo genético. Haciendo una estimación de la masa de la hélice, aplicó como función de coste una combinación entre este peso y la eficiencia aerodinámica.…”

“…Los B-splines [157] han sido utilizados frecuentemente para modelar ambas distribuciones de tal manera que se aproximen por curvas suaves, sin cambios bruscos. El diámetro de la hélice y el número de las palas son otros dos factores que se suelen especificar a la hora del diseño.…”