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this paper. Successful solutions to this issue depend on appropriate technology ideas.
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... study was four-phased and included experimental development and evaluation of advanced CCW high-lift configurations, development of pneumatic leading edge devices, computation evaluation of CCW airfoil designs, and evaluation of terminal-area performance employ- ing CCW. Figure 5 shows the high-lift and control surfaces for a conventional B737 and the B737/CCW air- craft. In its production version, the B737 employs a triple-slotted mechanical flap with leading edge slat. ...
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... 11, 12, and 13]. The channel wing, often referred to as the Custer Channel wing after its promoter Willard Custer, integrates the propeller flow with the wing aerodynamics by using the wing as a "shroud" in front of and below the propeller ( Figure 5). The propeller draws its flowstream over the wing, inducing high upper-surface flow velocities at low airspeeds. ...
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... test data [ref.8] from a small aircraft, a Piper PA-28 shown in figure 5, scaled theoretically to the size of a medium transport, have shown that the amount of vortex energy recovered by the wing-tip vortex turbine may be sufficient to generate the power required by an all electric aircraft system or a boundary layer control system [ref. 8]. ...
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... nozzles are often called 2-D (i.e., two-dimensional) because they use planar plates to divert flow. These nozzles can accommodate thrust reversal requirements as well, either by splitting a single vane and hinging it about its trailing edge to block flow or by pinching off the flow using multiple vanes ( Figure 5). Other pitch-vectoring nozzle designs include various gimballing nozzles and the single expansion ramp nozzle (SERN). ...
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... 1B ( Figure 5) is identical to Concept 1A with exception of three additional SnAPII tech- nologies. Wing-tip turbines are added for two purposes: to provide power for a suction pump powering a wing laminar flow control (LFC) system during cruise and to power a circulation control wing (CCW) during takeoff and landing. ...
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... 11 Based on the above two configurations, extensive researches on DPC have been carried out to demonstrate the advanced designs, performance improvement, practicality, and potentiality of the distributed propulsion system. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] As the important feature of DPC, BLI effect and the aerodynamic performance of a propulsion system were investigated by Plas. 29 A quantitative experiment on the ''silent aircraft'' showed that fuel consumption can be reduced by 3.8% due to the BLI effect. ...
The new distributed propulsion configuration (DPC) can effectively improve fuel efficiency and reduce pollution, but also brings in special cross-coupling effects between the flight and propulsion systems. To tackle this problem, integrated flight/propulsion modeling and optimal control of DPC with boundary layer ingestion (BLI) and supercirculation features are systematically investigated. As the basis, by taking the inherent BLI and supercirculation features into consideration, an integrated flight/propulsion model of SAX-40 is built to reflect the actual complex engine-aircraft coupling effects. Then an integrated flight/propulsion optimal control scheme is proposed to deal with the strong coupling effects and to implement the comprehensive control of redundant control surfaces as well as the distributed engines. Under this scheme, a detailed description of the optimal control problem is presented, and a novel two-stage optimization algorithm named genetic algorithm-random pattern search (GA-RPS) is proposed to solve this complex optimal problem. By the new strategies of “parallel genetic algorithm computing in sub-regions” and “random pattern search” in the GA-RPS algorithm, the optimization accuracy and convergence speed are effectively improved. Simulation results demonstrate the effectiveness of the GA-RPS algorithm and the significant performance improvement to DPC by optimization.
... This high-lift approach is adopted by the Collaborative Research Center SFB 880 of the Technische Universität Braunschweig 6 . Using blowing as a means for circulation control is not new and reviews of this technology appeared continuously over the last decades [8][9][10][11][12] . The blowing concepts shown in Figure 1 use the turbulent flow entrainment of a tangentially blown wall jet to keep the flow attached along the wall geometry with a high rate of turning. ...
Using the Coanda-effect in active high lift flaps opens the way to achieve large lift coefficients, needed for the design of aircraft with short takeoff and landing capabilities. In transport aircraft applications overall aircraft design requirements also call for low power consumption of the active high-lift system. Moreover, these aircraft need a reasonable stall angle for their operations. The present contribution describes recent research that aims at high-lift augmentation to be achieved with low rates of active blowing and with suited angle-of-attack ranges. The characteristics of well designed internally blown flaps are addressed. Of similar importance is the design of the leading edge where droop noses and slats may be introduced to avoid locally large boundary layer losses. Moreover, blowing of a Coanda wall jet over a flap can be combined with boundary layer suction in order to yield even higher efficiencies of the overall high-lift system.
... The integration of the propulsion system into the airframe in order to gain synergistic benefits requires advanced interaction between design tools and sophisticated aerodynamic investigation compared to a conventional tubeand-wing design with podded engines in the freestream. The main benefits aspired through distributed propulsion are increased propulsive efficiency, powered lift and reduced thrust requirement in case of a high number of propulsive devices [1][2][3]. ...
A shift in aircraft design paradigm is motivated by taking synergy effects of the airframe and propulsion system integration into account. A source of power saving not utilized in contemporary aircraft lies in the ingestion of the airframe-borne boundary layer by the propulsion system. A particularly beneficial arrangement has been identified in the architecture of the so-called Propulsive Fuselage, realized by a large fan rotating around the aft fuselage. A newly developed quasi-analytical aerodynamic method has been verified and compared to Computational Fluid Dynamics (CFD) results. It has demonstrated reasonable results compared to CFD calculations for a configuration like the Propulsive Fuselage. In order to increase applicability of the quasi-analytical methods in exploring the design space, the implementation of other propulsor configurations is necessary. This includes ducted fans and two-stage configurations, i.e. counter-rotating propellers and ducted counter-rotating fans.
... The resulting concepts are referred to as "vectored slipstream" for propeller aircraft, "externally blown flaps" for jet engines mounted close to the lower wing surface, and "upper surface blowing" for the jet engine located above the wing. These approaches have the potential of medium-powered lift coefficients achievable for a given thrust-to-weight ratio [3]. Higher-powered lift augmentation may be obtained by using internal blowing, such as blowing over Coanda surfaces close to the trailing edge. ...
The present study describes the fundamentals of droop nose design for improving the aerodynamics of airfoils with active high-lift using an internally blown Coanda-type flap. The main objectives are to increase the stall angle of attack and reduce the power required by the high-lift system. A two-dimensional sensitivity analysis explores the effects of varying airfoil camber and thickness in the first 20% of the chord. The resulting droop nose configuration improves the maximum lift coefficient by about 20% and increases the stall angle of attack by around 10-15 deg. A target lift coefficient of about 4.7 is reached with 28% less jet momentum coefficient, compared to the clean nose. As the modified leading-edge geometry presents different stall mechanisms, the aerodynamic response to variations of jet momentum is also different. In particular, for a jet momentum coefficient above 0.035, the stall angle of attack increases with jet momentum, in contrast with the behavior observed with the clean nose.
... The state of affairs can be summarized by Figure 1. The progress of Computational Fluid Dynamics (CFD) has spurred renewed interest in further investigation on Coandă effect and its use to enhance lift [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23]. Tangential jets that take advantage of Coandă effect to closely follow the contour of the body can lead to increased circulation in the case of airfoils, or drag reduction (or drag increase if desired) in the case of bluff bodies such as an aircraft fuselage. ...
... Figure 1 (a) Various methods of Circulation Control; (b) Powered Lift Chronology, from Synergistic Airframe-Propulsion Interactions and Integrations [11] (a) (b) (c) (d) (e) (f) Figure 2 ...
... Numerical results indicate that there exists an optimum Coandă jet configuration, which has been the subject of parametric study as exhibited in Figures 8 – 11 for S809 airfoil. A significant design parameter for boundary condition, which has been utilized to characterize Coandă jet application by many investigators [10] [11] [12] [13] [14] [15] [18] [19] [20], is specified by the momentum coefficient of the jet, C . ...
Motivated by attempts to enhance wind-turbine aerodynamic performance and efficiency, Coandă Jet Lift Enhancement for Circulation Control that has drawn great attention from researchers and industries is investigated numerically. Coandă Jet Circulation Control Techniques has a long history of development, although meticulous modeling and innovations for practical applications for energy conversion (such as for wind-turbine applications), aircraft wing lift enhancement and propulsion (such as for Coandă -MAV) are continually in progress. Along this line, the influence of Coandă effect for lift generation and enhancement is here investigated using two-dimensional CFD simulation. To that end, attention is focussed on Coandă jet configuration located at the trailing edge, to reveal the key elements that could exhibit the desired performance criteria for lift enhancement and drag reduction, or a combination of both. Parametric studies are carried out to obtain some optimum configuration, by varying pertinent airfoil geometrical and Coandă jet parameters. Particular attention is also given to turbulence modelling, by meticulous choice of appropriate turbulent models and scaling, commensurate with the grid generation, CFD code utilized and computational effectiveness. The present two-dimensional Coandă jet studies are carried out with wind turbine and micro-air-vehicle design in view, and discussed in the light of recent results from similar research.
... Three concepts ofFigure 2c use the approach of externally blown flaps by the propulsion exhaust. These approaches share the potential of medium powered lift coefficients achievable for a given engine thrust-to-weight ratio [6]. The externally upper surface blown flap is quite attractive since the jet engine exhaust can be re-distributed along a larger part of the wing span, and the noise of upper surface blowing is shielded by the wing. ...
Recent progress in numerical flow simulation methods and flow measurement techniques opens up new potentials for designing
and optimizing augmented high-lift systems. This research is directed towards substantially higher lift coefficients, needed
for future generations of quiet transport aircraft with short take-off and landing capabilities. Based upon a review of several
decades of powered lift research the present investigations focus on advanced circulation control concepts and their integration
with modern transonic wing sections. The gains of blowing moderate amounts of compressed air over carefully selected Coanda
surfaces are studied. Numerical flow field analysis is used to identify performance sensitivities and explore the design parameter
space. Directions of future research needed to mature this technology for transport aircraft applications are identified and
discussed.
Propulsion airframe integration design and analysis has many challenges as we move into the 21st century. Along with the conventional challenges of integrating a propulsion system on an aircraft, new technologies and new business drivers dictate innovative approaches to the design process be developed and applied.
On the technical side, new innovations in jet noise suppression and new aircraft concepts such as the blended wing body (BWB) will give rise to many challenges in propulsion system performance, operability, and meeting system requirements such as thrust reverse capability. Aircraft engine and aircraft manufacturers must have the appropriate design and analysis tools in place which provide the ability to react quickly to inevitable design changes, driven by constantly changing requirements, during the product development cycle.
On the business side, the rapid globalisation of the business dictates that the latest electronic technology be utilised to enable speed in communication with global customers as well as revenue sharing partners. More than ever, cost and schedules dictate the use of analytical methods to minimise the amount of qualification testing. Design and analysis software must be flexible and capable of integrating CAD/CAM and CAE tools while maintaining configuration control of the product.
The following paper describes some of the new technical challenges facing the industry. Innovative methods of addressing those challenges are described.
Airframe/propulsion integrated aerodynamic performance evaluation is one of the key technologies for hypersonic development. Hypersonic aircraft has the characteristics of high flatness ratio which its internal space is fully limited. If the force measurement balance takes up a lot of space when installed, it will make it difficult to install the engine and develop the wind tunnel test. Regarding the issue above, the force measurement and support integrated device is designed. First, the analysis of strength and modal are carried out to verify the response characteristics of the strength and frequency for the proposed device. Second, the integrated device was statically calibrated. The calibration result showed that the device has good linearity, sensitivity, and inter-channel interference. Finally, the aerodynamic load measurement tests under the Ma5.5, Ma6.0, Ma6.5 condition were conducted for a 2 m aircraft model in the
$\Phi 600$
pulse combustion wind tunnel. The maximum measurement error is 6.45%, which is the lift force output result in the Ma5.5. It has good consistency with the existing mature box balance. Therefore, the proposed device can meet the force test requirements of the hypersonic wind tunnel test.
The focus of the work is on the evaluation, development and integration of a robust actuator system for three-dimensional flow control of a blown Coanda flap to improve the high lift system of commercial aircraft. As part of the research work presented, the system is integrated into a wind tunnel model in order to influence the flow across the entire width of the model. The system developed is based on individual bending transducers that can vary the height of the blowing slot dynamically. The system is divided into 33 segments and is therefore able to implement static and dynamic actuation along the wing-span (3D-actuation). All segments can be controlled independently and thus offer great optimization potential for an effective flow control. Different configurations were developed and evaluated against each other with respect to the demanding requirements (small installation space, frequency range from 5 Hz to 300 Hz, 1 bar pressure, 0.4 mm deflection, 1 m span). The design of the blown flap has been specified in an iterative design process. In the final configuration, all mechanical components are reduced to the bare minimum for weight reduction reasons, in order to meet the dynamic requirements of the wind tunnel model. To characterize the lip segments, a test device has been designed that can be pressurized to generate aerodynamic loads on the lip segments. Finally, 33 lip segments were integrated into a wind tunnel model and tested intensively as part of a measurement campaign. The first aerodynamic results show an increase in lift of up to ∆Ca = 0.57. These aerodynamic gains are achieved at amplitudes that do not require the lip segments to completely close or open the blowing slot, which shows the advantage of the current lip design that enables activation with independently controlled stationary and unsteady components.
The conceptual design parameters and design processes which are used to access the development of the generic stability and control method are identified and discussed in Sect. 4.4. Primarily, design related commonalties and peculiarities for the range of conventional and unconventional aircraft types are considered.
