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Low Reynolds number air propeller profile determining method

An air propeller, a technology for determining methods, applied to propellers, aircraft parts, ground devices, etc., can solve the problems of not considering the decline of aerodynamic force, low propeller aerodynamic efficiency, and poor aerodynamic efficiency, so as to improve reliability and economy, avoid Work on designing airfoils and aerodynamic tests, optimizing the effect of the design process

Active Publication Date: 2017-07-14
CHINA ACAD OF AEROSPACE AERODYNAMICS
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AI Technical Summary

Problems solved by technology

In the conventional propeller design method, only the lift coefficient and lift-to-drag ratio are considered, but the aerodynamic force drop caused by low Reynolds is not considered, resulting in low aerodynamic efficiency of the propeller
[0003] In order to improve the aerodynamic efficiency of the propeller in the near space environment with low Reynolds number, some design methods use a specially designed low Reynolds number airfoil, but this airfoil has poor aerodynamic efficiency in conventional environments and is difficult to apply

Method used

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  • Low Reynolds number air propeller profile determining method
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  • Low Reynolds number air propeller profile determining method

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Embodiment Construction

[0032] Specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0033] Such as figure 1 As shown, the present invention proposes a kind of low Reynolds number air propeller profile determination method, according to propeller working basic index and initial condition, consider low Reynolds number to the lift coefficient of blade airfoil, lift-drag coefficient ratio (lift-drag) in the design process ratio), based on the propeller rigid spiral wake, the shape of the high-efficiency propeller is determined analytically. The steps are as follows:

[0034] (1) Determine the basic design indicators of the propeller, including: propeller speed Ω, number of propeller blades n, propeller diameter 2R, propeller tension T;

[0035] (2) Determine the propeller operating environment indicators, including: incoming flow velocity V 0 , operating height H and corresponding height air density ρ;

[0036] (3) Ac...

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Abstract

A low Reynolds number air propeller profile determining method comprises the technological approach of determining blade chord length distribution and corresponding torsional angle distribution. The influence of the Reynolds number on blade aerofoil aerodynamic performance is introduced in the low Reynolds number air propeller profile determining method. Based on a hypothesis of a propeller rigidity helical trailing vortex, the blade chord length and the torsional angle distribution of a propeller are solved through an analysis and iteration method, the optimal chord length and the optimal torsional angle distribution of blades under the low Reynolds number are obtained, and accordingly aerodynamic profile determining of the low Reynolds number air propeller is completed. Rapid and efficient determining of the low Reynolds number air propeller profile is achieved, the tension requirement is automatically met, and aerodynamic profile shaping of the low Reynolds number air propeller is completed with maximum efficiency.

Description

technical field [0001] The invention relates to a design method for a low Reynolds number propeller of a low-speed aircraft near space, and belongs to the technical field of propeller design. Background technique [0002] Near space low-speed aircraft (solar-powered drones, high-altitude hydrogen-powered drones) have great advantages in the fields of relay communication and military reconnaissance, but because their operating environment is near space with thin air, propeller propulsion It is the most favorable power mode at present. Near-space solar-powered aircraft generally fly at an altitude of 20km, and the Reynolds number is very low due to the low air density. Conventional propeller design methods only consider the lift coefficient and lift-to-drag ratio, but do not consider the aerodynamic drop caused by low Reynolds, resulting in low aerodynamic efficiency of the propeller. [0003] In order to improve the aerodynamic efficiency of the propeller in the near space ...

Claims

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Application Information

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IPC IPC(8): B64F5/00B64C11/18B64C11/20
CPCB64C11/18B64C11/20B64F5/00
Inventor 康传明贾永清刘峰陈柽李明新
Owner CHINA ACAD OF AEROSPACE AERODYNAMICS
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