scholarly journals Optimization of aerodynamic performance for co-axial rotors with different rotor spacings

2018 ◽  
Vol 10 (4) ◽  
pp. 362-369
Author(s):  
Yao Lei ◽  
Yuxia Ji ◽  
Changwei Wang
Keyword(s):  
Power Consumption ◽  
Aerodynamic Performance ◽  
Separation Distance ◽  
Power Coefficient ◽  
Axial Thrust ◽  
Thrust Coefficient ◽  
Hover Performance ◽  
Power Loading ◽  
Blade Tip ◽  
Aerodynamic Interference

In this article, attempts are made to study the aerodynamic performance of co-axial rotors with different rotor spacings in hover. A custom-designed experimental platform with seven rotor spacings ( z/D = 0.16, 0.19, 0.23, 0.26, 0.29, 0.33 and 0.38) is applied to measure the hover performance, i.e. co-axial thrust and power consumption, and to optimize the aerodynamic configuration of the co-axial system. The experimental errors in thrust coefficient, power coefficient and power loading calculated through ‘Kline-McClintock equation’ are less than 2%. Additionally, the streamline distribution and pressure of blade tip at different rotor spacings obtained from numerical simulations are presented to visualize the effects of aerodynamic interference between the top and bottom rotor. Results show that the aerodynamic performance of a co-axial rotor with the specific rotor configure and speed range can be indeed improved by changing the rotor spacing, and the optimal performance is obtained with a rotor spacing of 0.19. Also, the magnitude of aerodynamic interference related to the axial separation distance has demonstrated to be beneficial on the total thrust and power consumption. For the same disc loading, a decrease in rotational speed results in an increase in power loading especially for z/D = 0.19. It is also found that the bottom rotor does affect the performance of the top rotor at smaller rotor spacings, whereas the effect is significantly reduced as the rotor spacing increases.

scholarly journals Aerodynamic Characteristics of a Micro Multi-Rotor Aircraft with 12 Rotors Considering the Horizontal Wind Disturbance

2020 ◽  
Vol 10 (20) ◽  
pp. 7387
Author(s):  
Yao Lei ◽  
Wenjie Yang ◽  
Hengda Wang
Keyword(s):  
Power Consumption ◽  
Micro Air Vehicles ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Wind Disturbance ◽  
Wind Speeds ◽  
Hover Performance ◽  
Blade Tip ◽  
Cfd Method

Wind disturbance posed difficulties for the stability of the micro air vehicles (MAVs) with attitude variation. In this paper, the aerodynamic performance of a MAV with six coaxial rotor pairs considering the horizontal wind is investigated by both experiments and numerical simulations. First, the effect of the horizontal wind on the multi-rotor aircraft is analyzed in detail. Then, low-speed wind tunnel tests were performed to obtain the thrust and power consumption and the aerodynamic performance of the multi-rotor aircraft (l/D = 1.2 and h/D = 0.19) with the rotational speed of 1500–2300 r/min in the horizontal wind ranged from 0 to 5 m/s. Finally, the distribution of streamline, the pressure of the blade tip, and the velocity and the vortices in the flow field of a multi-rotor aircraft with horizontal wind disturbance, were simulated and studied using the computational fluid dynamics (CFD) method. Through the comparison of experimental results and simulation results, it can be seen that the horizontal wind disturbance will increase power consumption to weaken the aerodynamic performance at higher rotor speeds. However, larger thrust and better hover performance are obtained at lower rotational speeds with good wind resistance. Additionally, due to the mutual induction between rotor wakes, the interactions of downwash flows become more intense at higher rotational speeds or larger wind speeds where the vortexes at the blade tip deformed and moved along with the wind.

scholarly journals Effect of Rotor Spacing and Duct Diffusion Angle on the Aerodynamic Performances of a Counter-Rotating Ducted Fan in Hover Mode

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1338
Author(s):  
Woo-Yul Kim ◽  
Santhosh Senguttuvan ◽  
Sung-Min Kim
Keyword(s):  
Steady State ◽  
Numerical Model ◽  
Figure Of Merit ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Flow Conditions ◽  
Thrust Coefficient ◽  
Ducted Fan ◽  
Aerodynamic Performances ◽  
Rotor Model

The aerodynamic performance of a counter-rotating ducted fan in hover mode is numerically analyzed for different rotor spacings and duct diffusion angles. The design of the counter-rotating fan is inspired by a custom-designed single rotor ducted fan used in a previous study. The numerical model to predict the aerodynamic performance of the counter-rotating ducted fan is developed by adopting the frozen rotor approach for steady-state incompressible flow conditions. The relative angle between the front and the rear rotor is examined due to the usage of the frozen rotor model. The results show that the variation of thrust for the different relative angles is extremely low. The aerodynamic performances are evaluated by comparing the thrust, thrust coefficient, power coefficient, and figure of merit (FOM). The thrust, thrust coefficient, and FOM slightly increase with increasing rotor spacing up to 200 mm, regardless of the duct diffusion angle, and reduce on further increase in the rotor spacing. The duct diffusion angle of 0° generates about 9% higher thrust and increases the FOM by 6.7%, compared with the 6° duct diffusion angle. The duct diffusion angle is highly effective in improving the thrust and FOM of the counter-rotating ducted fan, rather than the rotor spacing.

scholarly journals The aerodynamic performance of Non-planar hex-rotors aircraft subjected the horizontal wind disturbanceLei yao1,2* Ma Chensong1 Feng Zhicheng1

2021 ◽  
Author(s):  
Lei yao ◽  
Ma Chensong ◽  
Feng Zhicheng
Keyword(s):  
Wind Speed ◽  
Power Consumption ◽  
Tilt Angle ◽  
Wind Tunnel Test ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Horizontal Wind Speed ◽  
Power Loading ◽  
Experimental Values ◽  
Cfd Method

Abstract The non-planar hex-rotor aircraft mentioned in this article can change its flight status by simply changing the tilt angle of the rotor. In this paper, mainly studied the best aerodynamic performance of a non-planar hex-rotor aircraft under the influence of horizontal wind (0m/s, 2.5m/s and 4m/s). Firstly, the rotation speed of the rotor is a fixed value (2200r/min) in the low-speed wind tunnel test, the horizontal wind speed and the tilt angle of the rotor are variable values, the thrust, power consumption and power loading(PL) values of the aircraft are obtained. Secondly, the computational fluid dynamics(CFD) method is used to simulate the aerodynamic performance of a non-planar hex-rotors aircraft when subjected to a horizontal wind to obtain the simulation results. Finally, comparing the experimental values and the simulation values, it is found that the horizontal speed has a greater impact on the thrust and power consumption of the non-planar hex-rotor aircraft. From the change of PL values, it is concluded that the horizontal wind speed is 0m/s, 2.5m/s, 4m/s, the best inclination angle is 10°, 30°and 50°, and the strongest anti-wind performance.

scholarly journals Horizontal Wind Effect on the Aerodynamic Performance of Coaxial Tri-Rotor MAV

2020 ◽  
Vol 10 (23) ◽  
pp. 8612
Author(s):  
Yao Lei ◽  
Yiqiang Ye ◽  
Zhiyong Chen
Keyword(s):  
Wind Tunnel ◽  
Power Consumption ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Wind Effect ◽  
Rotor Speed ◽  
Wind Tunnel Experiments ◽  
Air Vehicle ◽  
Power Loading

The coaxial Tri-rotor micro air vehicle (MAV) is composed of three coaxial rotors where the aerodynamic characteristics of is complicated in flight especially when the wind effect is introduced. In this paper, the hovering performance of a full-scale coaxial Tri-rotor MAV is analyzed with both the simulations and wind tunnel experiments. Firstly, the wind effect on the aerodynamic performance of coaxial Tri-rotor MAV is established with different rotor speed (1500–2300 rpm) and horizontal wind (0–4 m/s). Secondly, the thrust and power consumption of coaxial Tri-rotor (L/D = 1.6) were obtained with low-speed wind tunnel experiments. Furthermore, the streamline distribution, pressure distribution, velocity contour and vortex distribution with different horizontal wind conditions are obtained by numerical simulations. Finally, combining the experiment results and simulation results, it is noted that the horizontal wind may accelerate the aerodynamic coupling, which resulting in the greater thrust variation up to 9% of the coaxial Tri-rotor MAV at a lower rotor speed. Moreover, the aerodynamic performance is decreased with more power consumption at higher rotor speed where the wind and the downwash flow are interacted with each other. Compared with no wind flow, the shape of the downwash flow and the deformation of the vortex affect the power loading and figure of metric accordingly.

scholarly journals Aerodynamic Optimization of a Micro Quadrotor Aircraft with Different Rotor Spacings in Hover

2020 ◽  
Vol 10 (4) ◽  
pp. 1272 ◽  
Author(s):  
Yao Lei ◽  
Hengda Wang
Keyword(s):  
Numerical Simulations ◽  
Negative Impact ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Aerodynamic Optimization ◽  
Quadrotor Aircraft ◽  
Blade Tip ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Interference ◽  
Cfd Method

In order to study the aerodynamic performance of the quadrotor with different rotor spacings in hover, experiments were performed together with numerical simulations. For experimental study, an experimental platform was designed to measure the thrust and power consumption of the quadrotor with different rotor spacings (L/R = 2.2, 2.6, 3.0, 3.2, 3.6, and 4.0), and to attempt to find out the optimal rotor configuration which makes the quadrotor have the best aerodynamic performance. In addition, the pressure distribution, vorticity of the blade tip, and velocity vector of quadrotor in the flow field were obtained by Computational Fluid Dynamics (CFD) method to visually analyze the aerodynamic interference between adjacent rotors. By the comparison of experimental results and numerical simulations, the final results show that the aerodynamic performance of the quadrotor varies obviously with the change of rotor spacing, and it has a negative impact on hover efficiency if rotor spacing is too much small or large. The rotors pacing at L/R = 3.6 with larger thrust and smaller power is considered to be the best aerodynamic configuration for the quadrotor with better aerodynamic characteristics. Furthermore, compared with the isolated rotor, moderate aerodynamic interference is proved to help improve the aerodynamic performance of the quadrotor with a larger thrust, especially for a rotor spacing at L/R = 3.6.

scholarly journals Aerodynamic Performance of Hex-Rotor UAV Considering the Horizontal Airflow

2019 ◽  
Vol 9 (22) ◽  
pp. 4797
Author(s):  
Yao Lei ◽  
Mingxin Cheng
Keyword(s):  
Wind Tunnel ◽  
Numerical Simulations ◽  
Aerodynamic Performance ◽  
Wind Tunnel Experiments ◽  
Low Speed ◽  
Pressure Distributions ◽  
Hover Performance ◽  
Power Loading ◽  
Aerial Vehicle ◽  
Low Speed Wind Tunnel

In this paper, the aerodynamic performance of a Hex-rotor unmanned aerial vehicle (UAV) with different rotational speeds (1500–2300 RPM) considering the horizontal airflow conditions is analyzed by both simulations and experiments. A low-speed wind tunnel experiments platform is applied to measure the thrust, torque, and power consumption of a Hex-rotor UAV with different rotational speeds in horizontal airflow, which varied from 0 m/s–4 m/s. First, this paper introduces the effect of horizontal airflow on a UAV. Then, the low-speed wind tunnel experiments were carried out on a Hex-rotor UAV (D/L = 0.56) with different horizontal velocities to determine the hover performance. Finally, numerical simulations were obtained with the streamline distributions, pressure distributions, velocity contour, and vortex distributions at different horizontal airflow conditions to describe the aerodynamic interference effect of different horizontal airflows. Combined with the experimental results and numerical simulations results, the horizontal airflow proved to have a significant influence on the aerodynamic performance of the Hex-rotor UAV with an increase in thrust and power. Indeed, the streamlines in the flow field were coupled to each other at the presence of the incoming airflow. Especially when the incoming airflow was larger, the Hex-rotor UAV could properly use low-speed flight to maintain high power loading. Finally, it is inferred that the aerodynamic performance of the Hex-rotor UAV is also related to the movement and deformation of the vortex at the tip of the rotor.

scholarly journals Aerodynamic Performance Characterization of Slotted Propeller: Part B Effect of Angle

2019 ◽  
Vol 11 (4) ◽  
pp. 155-170
Author(s):  
Aravind SEENI
Keyword(s):  
Rotational Speed ◽  
Aerodynamic Performance ◽  
Von Mises Stress ◽  
Power Coefficient ◽  
Small Scale ◽  
Propeller Blade ◽  
Static Structure ◽  
Thrust Coefficient ◽  
Advance Ratio ◽  
Von Mises

In this paper, designs of slotted propeller blade were discussed numerically, in terms of aerodynamic performance and static structural analysis. Baseline APC Slow Flyer 10’ x 7’ small scale propeller blade was modified by including slots along the propeller blade. Numerical analysis has been done to determine the influence of slots angle towards thrust coefficient, power coefficient and efficiency. Simulations were performed by using ANSYS Fluent implementing k-ω turbulence model and Multiple Reference Frame to incorporate rotational speed of the propeller. The analyses were conducted at a fixed rotational speed, with variance of advance ratio. Initial slotted design is set at 180 degree and the angles were changed with 10-degree interval, ranging from 180 degree to 90 degree. The results were compared with available experimental data. For the slotted design, the result shows that inducing slots do not always lead to improvement in propeller blade performance. Improvement in thrust coefficient with the range of 0.267% to 2.71% can be seen for low advance ratio for most of slot angles. However, a significant increase in power coefficient can be observed which reduces the overall efficiency of the propeller blade. For stress and deformation, ANSYS Mechanical Static Structure was used to determine maximum Von-Mises stress, maximum Von-Mises strain, and total deformation. The analyses were conducted by using 60% long strand fiber glass reinforced nylon 6 Natural. The blade is more suitable to operate at higher velocity. At lower operational velocity, the blade tends to experience material failure as the stress exceeds stress at break.

Experimental investigations on high altitude airship propellers with blade planform variations

2017 ◽  
Vol 232 (16) ◽  
pp. 2952-2960 ◽  
Author(s):  
Zhenchen Liu ◽  
Peiqing Liu ◽  
Tianxiang Hu ◽  
Qiulin Qu
Keyword(s):  
Wind Tunnel ◽  
High Altitude ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Experimental Investigations ◽  
Propulsive Efficiency ◽  
Higher Power ◽  
Blade Tip ◽  
Limited Power ◽  
Advance Ratio

Wind tunnel tests of five propellers with different blade tip widths are carried at pitch angles between 20.5° and 40°. The aerodynamic performance are provided, which can be treated as a supplement of the high altitude airship propeller database. The influences of the blade planform and advance ratio on both power coefficient and propulsive efficiency are analyzed. It is found that at advance ratio below 0.8, the propeller with narrow tip has higher efficiency but limited power coefficient. While at advance ratio above 0.8, the propeller with wider tip has the advantages of higher power coefficient and acceptable efficiency. The variation of the propulsive efficiency with planform and advance ratio is dominated by the radial distributions of the airflow angle and interference angle.

A New Multi-Objective Evolutionary Algorithm for Optimizing the Aerodynamic Design of HAWT Rotor

2014 ◽  
Author(s):  
Ekhlas M. Alfayyadh ◽  
Sadeq H. Bakhy ◽  
Yasir M. Shkara
Keyword(s):  
Genetic Algorithm ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Aerodynamic Design ◽  
Thrust Coefficient ◽  
Blade Element Momentum Theory ◽  
Multi Objective ◽  
Momentum Theory ◽  
Bem Theory ◽  
Blade Element

This paper presents a new multi-objective evolutionary algorithm (MOEA) for optimum aerodynamic design of horizontal-axis wind turbines (HAWT). The design problem is set to find the blade shape such that optimizing multi-objective at different airfoil profiles. Combined Blade Element Momentum (BEM) theory and two different algorithms (Genetic (GA) and Enumeration) are used. Flow around subsonic airfoils is analyzed using XFOIL software. WINDMEL III wind turbine is selected to improve its aerodynamic performance with different airfoil profiles technique of National Renewable Energy Laboratory (NREL) family. Employing Genetic Algorithm embodied in Blade Element Momentum theory to calculate power, thrust and starting torque coefficients that are the fitness function. Another method, Enumeration method, is used to enhance evolutionary method results. The optimum solution acquired from combination of Genetic Algorithm and Blade Element Momentum theory of three blades configuration increased power coefficient by (25.8 %) and thrust coefficient by (16.6%). Enumeration method results increased power coefficient by (13.8%), while thrust coefficient decreased by (0.2%) from the original design. In general, the evolutionary method of combined GA and BEM theory with different airfoil profiles technique improved the turbine aerodynamic performance, and the results are in good agreement with other published papers.

Influence of Blade Tip Fillet Structure on Aerodynamic Performance of a Compressor Rotor

2021 ◽  
Author(s):  
HAO HAO WANG ◽  
Lei Zhao ◽  
Limin Gao ◽  
Yongzeng Li ◽  
Chi Ma
Keyword(s):  
Aerodynamic Performance ◽  
Compressor Rotor ◽  
Blade Tip
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