Aerodynamic Design, Analysis and Validation of a Small Blended-Wing-Body Unmanned Aerial Vehicle

This paper describes the aerodynamic design and assessment of a blended-wing–body (BWB) configuration under the distributed electric propulsion (DEP) installation constraints. The aerodynamic design rationale and process is described, as well as how the DEP system is considered and simplified in the optimization design process. Both the BWB configuration and the DEP induced effects are numerically simulated and analyzed using the Reynolds Averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) flow solvers. To further demonstrate the feasibility and reliability of the design approach, the wind tunnel tests of a scaled model of the designed BWB configuration are carried out, and both the aerodynamic characteristics and the BWB surface flow are measured and analyzed. The results indicate the reliability and feasibility of the optimization design method introduced in this paper.

Conceptual design of Blended Wing Body for Future Air Transportation

Blended wing body is a fixed wing aircraft which are smoothly blended together with no clear dividing line and no distinct wings also be given a wide Aerofoil shaped body. The future transportation is of aircrafts will incline towards the aerodynamically efficient and capable of carrying large number of passengers over long range and environmental benefits is the main paradigm in the design of aircraft BWB has a high lift to drag ratio which increases the CL max and velocity of the airplane with high load factor and high economy compared with traditional aircraft. Evacuation pressure or the cabin pressurization is the major issues in most of the designs with the minimum aerodynamic lift coefficient and drag coefficient. On the other side of the trend is towards the increasing cruise speed. High speed flow is connected with overcoming of intensive drag rise accruing due to existence of intensive shock, closing local area of supersonic flow. Increase of flight Mach number is possible only by using flow control methods and through affecting the shock increases of aspect ratio leads to increase of lift coefficient corresponding to maximal lift to drag. High bypass ratio engines have smaller fuel consumption and lower noise level but have negative effect on flow around airframe including take-off and landing phases. The necessity of solving problem of intensive aerodynamic heating of surface element of flight vehicles and by ensuring of their stability and controllability and also by need of implementing of high-volume tanks for hydrogen fuel and super high bypass ratio engines.

A key design parameter proposal for aerodynamically efficient subsonic blended wing body

Purpose Blended wing body (BWB) is a very advantageous design in terms of low fuel consumption, low emission and low noise levels. Because of these advantages, the BWB is a candidate to become the commercial passenger aircraft of the future by providing a paradigm shift in conventional designs. This paper aims to propose a key design parameter for wing sizing of subsonic BWB and a performance parameter for calculating the lift/drag ratio values of BWBs. Design/methodology/approach The parameter proposed in the study is based on the square/cube law, that is, the idea that the wetted area is proportional to the power of 2/3 of the weight. Data on the weight, wing area, wingspan, lift-to-drag (L/D) ratio for 19 BWB used in the analyzes were compiled from the published literature and a theoretical methodology was developed to estimate the maximum lift to drag ratio of BWBs. The accuracy of the proposed key design parameter was questioned by comparing the estimated L/Dmax values with the actual values. Findings In the current study, it is claimed that the wingspan/(take-off gross weight)(1/3) parameter provides an L/D efficiency coefficient regardless of aircraft size. The proposed key design parameter is useful both for small-scale BWB, that is unmanned aerial vehicles BWB and for large-scale BWB designs. Therefore, the b/Wg(1/3) parameter offers a dimensionless L/D efficiency coefficient for BWB designs of different scales. The wetted aspect ratio explains how low aspect ratio (AR)-BWB designs can compete with high AR-tube-and-wing designs. The key parameter is also useful for getting an idea of good or bad BWB with design and performance data published in the literature. As a result, reducing the blending area and designing a smaller central body are typical features of aerodynamically efficient BWB. Originality/value As the role of the square/cube law in the conceptual aircraft design stage has not been sufficiently studied in the literature, the application of this law to BWBs, a new generation of designs, makes the study original. Estimation of the wetted area ratio using only wingspan and gross weight data is an alternative and practical method for assessing the aerodynamic performance of the BWB. According to the model proposed in the current study, reducing the take-off gross weight of the BWBs using lighter building materials and designing with a larger wingspan (b) are the main recommendations for an aerodynamically efficient BWB.

Effects of wing twist on lift and drag characteristics of blended wing body aircraft

Blended Wing Body is a revolutionary concept offering phenomenal performance advantages over conventional aircraft. There are various aerodynamic features that are added to the wing in order to adjust the lift distribution and wing twist is one of them. This paper presents a progressive study to examine the effects of twist angles on the aerodynamic characteristics of a Blended Wing Body (BWB) aircraft. CFD analysis is carried out on seven BWB models having wing twists ranging from +3° to -3°. Each model is analyzed at four different Mach numbers. The coefficient of drag (Cd) and coefficient of lift (Cl) is determined and plotted against the twist angle to obtain a trend. The Cl/Cd ratio is also calculated to observe the overall aerodynamic performance of the BWB.

Design of Elevons, Wings, and Performance Investigation for A Blended Wing Body UAV

Objectives: To study a hybrid VTOL- Blended wing body design for its wings and elevons and perform CFD simulations with the wings. The steps for designing wing configuration and Elevon positioning involve different variables giving rise to a large number of design possibilities for a control surface. In the current study methods, have been proposed for the selection of optimized wing configuration and elevons positioning and validated with simulations model. Methods: Meta-heuristic methods like genetic algorithms are used for arriving at favorable solutions and Matlab coding is written for the initial draft of wing geometry, selected geometries are iterated in XFLR5 for stability and control, and later validated with simulations around the fluid domain. Elevons are control surfaces generally installed in tailless aircraft at the wing's trailing edge. It applies to roll and pitching force to wings as it combines the functionality of both pitching and rolling control. Design space was mathematically plotted and solved using MATLAB to decide elevons, wing configuration, and their positions.Findings: Initial selection of wing geometry, aoa, and structural design for maneuverability and stability for the enhanced aerodynamic performance of BWB UAV. In this presented paper drag coefficient of the designed BWB UAV comes out to be precisely around 0.02216 using computational modeling. Variation curve of Lift and drag coefficient with aspect ratio and angle of attack. Post-processing results of pressure forces and velocity profile on Wings accurately validate the proposed method of control surface optimization. Novelty: Designed BWB UAV has increased lift to drag ratio, reduced weight of airframe which improves performance. The Design phase is highly iterative, Through this research paper, an attempt has been made to develop a methodology for selection and investigation of control surfaces against requirements that makes BWB UAV more helpful for practical use and increasing the lift and endurance efficiency of the hybrid VTOL- Blended wing body aircraft.

Power Fan Design of Blended-Wing-Body Aircraft with Distributed Propulsion System

A blended-wing-body aircraft has the advantages of high lift-to-drag ratio, low noise, and high economy compared with traditional aircraft. It is currently a solution with great potential to become a future civilian passenger aircraft. However, most airplanes with this layout use distributed power, and the power system is on the back of the fuselage, with embedded or back-supported engines. This type of design causes the boundary layer suction effect. The boundary layer ingestion (BLI) effect can fill the wake of the aircraft and improve the propulsion efficiency of the engine. However, it causes huge design difficulties, especially when the aircraft and the engine are strongly coupled. In this paper, an aircraft with a coupled engine configuration is studied. The internal and external flow fields are calculated through numerical simulation. A realistic calculation model is obtained through the coupling of boundary conditions. On the basis of the influence of the external flow on the internal flow under the coupled condition, the influence of the BLI effect on the aerodynamic performance of the fan is investigated.