Aerodynamic benefits of boundary layer ingestion for distributed propulsion configuration

2019 ◽  
Vol 91 (10) ◽  
pp. 1285-1294 ◽  
Author(s):  
Jing Zhang ◽  
Wenwen Kang ◽  
Lingyu Yang
Keyword(s):  
Boundary Layer ◽  
Reference Value ◽  
Aerodynamic Characteristics ◽  
Comprehensive Analysis ◽  
Propulsion System ◽  
Analysis Method ◽  
Content Type ◽  
Model Based ◽  
Distributed Propulsion ◽  
Lift And Drag

Purpose Boundary layer ingestion (BLI) is one of the probable noteworthy features of distributed propulsion configuration (DPC). Because of BLI, strong coupling effects are generated between the aerodynamics and propulsion system of aircraft, leading to the specific lift and drag aerodynamic characteristics. This paper aims to propose a model-based comprehensive analysis method to investigate this unique aerodynamic. Design/methodology/approach To investigate this unique aerodynamics, a model-based comprehensive analysis method is proposed. This method uses a detailed mathematical model of the distributed propulsion system to provide the essential boundary conditions and guarantee the accuracy of calculation results. Then a synthetic three-dimensional computational model is developed to analyze the effects of BLI on the lift and drag aerodynamic characteristics. Findings Subsequently, detailed computational analyses are conducted at different flight states, and the regularities under various flight altitudes and velocities are revealed. Computational results demonstrate that BLI can improve the lift to drag ratio evidently and enable a great performance potentiality. Practical implications The general analysis method and useful regularities have reference value to DPC aircraft and other similar aircrafts. Originality/value This paper proposed a DPS model-based comprehensive analysis method of BLI benefit on aerodynamics for DPC aircraft, and the unique aerodynamics of this new configuration under various flight altitudes and velocities was revealed.

Model-based analysis of boundary layer ingestion effect on lateral-directional aerodynamics using differentiated boundary conditions

2016 ◽  
Vol 231 (13) ◽  
pp. 2452-2463
Author(s):  
Jing Zhang ◽  
Xianfa Zeng ◽  
Lingyu Yang
Keyword(s):  
Boundary Layer ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Propulsion System ◽  
Computational Method ◽  
Body Type ◽  
Detailed Model ◽  
Model Based ◽  
Distributed Propulsion

The noteworthy feature of aircraft with distributed propulsion configuration is the integration of a blended-wing-body type airframe and an embedded distributed propulsion system, thus inducing the specific boundary layer ingestion effect. Different boundary layer ingestion effects on the distributed engines may generate asymmetric flow fields on the airframe surface, and then lead to the unique lateral-directional aero-propulsive close coupling. To investigate the lateral-directional aerodynamics influenced by boundary layer ingestion, a new comprehensive computational method based on the differentiated boundary conditions is proposed. This method uses a synthetic three-dimensional computational model including the airframe and multi-engine to analyze the aerodynamic characteristics, and the essential boundary conditions can be extracted from the thermodynamic distributed propulsion system model to represent the different boundary layer ingestion intensities on the left and right engines. Subsequently, detailed model-based analyses of boundary layer ingestion influences on the lateral-directional aerodynamic characteristics are conducted, and the influence regularities under different flight states are revealed. All the results demonstrate that the differentiated boundary layer ingestion intensities on distributed engines can certainly affect the roll and yaw aerodynamic performance of the distributed propulsion configuration aircraft.

Development of a testing methodology for high-altitude propeller

2018 ◽  
Vol 90 (9) ◽  
pp. 1486-1494
Author(s):  
Jun Jiao ◽  
Bifeng Song ◽  
Yubin Li ◽  
Yugang Zhang ◽  
Jianhua Xu
Keyword(s):  
High Altitude ◽  
Aerodynamic Characteristics ◽  
Propulsion System ◽  
Testing System ◽  
Content Type ◽  
Testing Methodology ◽  
Mobile Testing ◽  
High Altitude Platforms ◽  
Key Techniques ◽  
Different Altitudes

Purpose The purpose of this paper is to develop a propeller performance measurement method for high-altitude platforms by analyzing of the propeller aerodynamic characteristics and application of a mobile testing system. Design/methodology/approach An experimental approach is adopted for this study. Considering the aerodynamic characteristics of the high-altitude propeller, the similitude of the scaled propeller model in the experiment is analyzed and determined. Then, the experimental method and procedure to obtain the propeller’s performance under different altitudes are presented, and the structure of hardware and software and the key techniques of the testing system are introduced in detail. Findings The applicability and effectiveness of the testing system is verified through comparison between experimental and numerical results. In addition, the performance of the 6.8-m propeller for a high-altitude airship is tested, which proves that the high-altitude propeller can meet the requirements of the propulsion system. Practical implications The testing methodology and the mobile testing system could be applied to aerodynamic performance evaluation of the high-altitude propellers under different altitudes. Originality/value This testing approach exhibits significant time and cost benefits over many other experimental methods to obtain the performance of the high-altitude propellers, which is important in the preliminary design of the propulsion system for high-altitude platforms.

Thermal cycle analysis of turboelectric distributed propulsion system with boundary layer ingestion

2013 ◽  
Vol 27 (1) ◽  
pp. 163-170 ◽  
Author(s):  
Chengyuan Liu ◽  
Georgios Doulgeris ◽  
Panagiotis Laskaridis ◽  
Riti Singh
Keyword(s):  
Boundary Layer ◽  
Thermal Cycle ◽  
Propulsion System ◽  
Distributed Propulsion

Performance Analysis of a Distributed Propulsion System with Boundary Layer Ingestion

2015 ◽  
Author(s):  
Esteban A. Valencia ◽  
Chengyuan Liu ◽  
Laskaridis Panagiotis ◽  
Riti Singh ◽  
Devaiah Nalianda
Keyword(s):  
Boundary Layer ◽  
Performance Analysis ◽  
Propulsion System ◽  
Distributed Propulsion

Identification of a degradation of aerodynamic characteristics of a paraglider due to its flexibility from flight test

2019 ◽  
Vol 91 (6) ◽  
pp. 873-879 ◽  
Author(s):  
Robert Kulhánek
Keyword(s):  
High Speed ◽  
Aerodynamic Drag ◽  
Leading Edge ◽  
Flight Test ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Content Type ◽  
Specific Geometry ◽  
Lift And Drag ◽  
Scaled Models

Purpose Aerodynamics of paragliders is very complicated aeroelastic phenomena. The purpose of this work is to quantify the amount of aerodynamic drag related to the flexible nature of a paraglider wing. Design/methodology/approach The laboratory testing on scaled models can be very difficult because of problems in the elastic similitude of such a structure. Testing of full-scale models in a large facility with a large full-scale test section is very expensive. The degradation of aerodynamic characteristics is evaluated from flight tests of the paraglider speed polar. All aspects of the identification such as pilot and suspension lines drag and aerodynamics of spanwise chambered wings are discussed. The drag of a pilot in a harness was estimated by means of wind tunnel testing, computational fluid dynamics (CFD) solver was used to estimating smooth wing lift and drag characteristics. Findings The drag related to the flexible nature of the modern paraglider wing is within the range of 4-30 per cent of the total aerodynamic drag depending on the flight speed. From the results, it is evident that considering only the cell opening effect is sufficient at a low-speed flight. The stagnation point moves forwards towards the nose during the high speed flight. This causes more pronounced deformation of the leading edge and thus increased drag. Practical implications This paper deals with a detailed analysis of specific paraglider wing. Although the results are limited to the specific geometry, the findings help in the better understanding of the paraglider aerodynamics generally. Originality/value The data obtained in this paper are not affected by any scaling problems. There are only few experimental results in the field of paragliders on scaled models. Those results were made on simplified models at very low Reynolds number. The aerodynamic drag characteristics of the pilot in the harness with variable angles of incidence and Reynolds numbers have not yet been published.

Research on transient aerodynamic characteristics of windshield wipers of vehicles

2019 ◽  
Vol 29 (8) ◽  
pp. 2870-2884
Author(s):  
Zhen Chen ◽  
Zhenqqi Gu ◽  
Tao Jiang
Keyword(s):  
Drag Force ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Dynamic Mesh ◽  
Research Association ◽  
Content Type ◽  
Dynamic Mesh Technique ◽  
Lift And Drag ◽  
Mesh Technique ◽  
Aerodynamic Lift

Purpose The main purpose of this paper is to gain a better understanding of the transient aerodynamic characteristics of moving windshield wipers. In addition, this paper also strives to illustrate and clarify how the wiper motion impacts the airflow structure; the aerodynamic interaction of two wipers is also discussed. Design/methodology/approach A standard vehicle model proposed by the Motor Industry Research Association and a pair of simplified bone wipers are introduced, and a dynamic mesh technique and user-defined functions are used to achieve the wiper motion. Finite volume methods and large eddy simulation (LES) are used to simulate the transient airflow field. The simulation results are validated through the wind tunnel test. Findings The results obtained from the study are presented graphically, and pressure, velocity distributions, airflow structures, aerodynamic drag and lift force are shown. Significant influences of wiper motion on airflow structures are achieved. The maximum value of aerodynamic lift and drag force exists when wipers are rotating and there is a certain change rule. The aerodynamic lift and drag force when wipers are rotating downward is greater than when wipers are rotating upward, and the force when rotating upward is greater than that when steady. The aerodynamic lift and drag forces of the driver-side wiper is greater than those of the passenger-side wiper. Originality/value The LES method in combination with dynamic mesh technique to study the transient aerodynamic characteristics of windshield wipers is relatively new.

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