Numerical modeling of coanda effect in a novel propulsive system

Das, Shyam; Abdollahzadeh, M.; Páscoa, José; Dumas, Antonio; Trancossi, Michele

doi:10.1260/1750-9548.8.2.181

Cited by 18 publications

(5 citation statements)

References 48 publications

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“…При низких тепловых нагрузках, движущиеся струи пара прилипают к внутренним стенкам ТТ и направление закрутки парового вихря происходит от периферии к центру парового канала. Причиной неустойчивого течения и прилипания струй пара к стенкам канала является влияние эффекта Коанда [41,42], что и приводит к возникновению вращения паровых струй от стенок к центральной оси канала и формированию тороидального вихревого кольца.…”

Section: результаты численного моделированияunclassified

The study of condensable vapour vortex flow in short low temperature heat pipes

Seryakov¹

2019

Journal IAR

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Представлены результаты компьютерных исследований вихреобразования и изменения направления вращения парового вихря внутри коротких линейных тепловых труб (ТТ) с выполненным в виде сопла Лаваля паровым каналом. Впервые установлено, что паровой тороидальный вихрь, возникающий в результате взаимодействия потока влажного пара с нормально ориентированной плоской верхней крышкой ТТ может изменять направление своего вращательного движения. При небольшом температурном напоре на испаритель направление вращения парового вихря за счет эффекта Коанда и прилипания движущихся струй пара к стенкам происходит от периферии к продольной оси канала. При этом радиальное течение пленки конденсата по верхней крышке к расположенной на стенках канала капиллярно-пористой вставке и направление движения прилегающих слоев парового вихря оказываются встречными. Паровой вихрь за счет поверхностного трения замедляет течение пленки конденсата по верхней крышке ТТ и тем самым увеличивает ее эффективную толщину. При увеличении температурного напора на испаритель направление вращения парового вихря изменяется на противоположное, от продольной оси к периферии парового канала, и направления вращения прилегающих слоев пара и течения пленки жидкого конденсата становятся спутными, что приводит к резкому уменьшению эффективной толщины пленки. Экспериментальные результаты измерений толщины пленки жидкого конденсата, полученные с помощью емкостных датчиков, также показывают резкое уменьшение ее толщины при увеличении температурного напора на испаритель ТТ, что может быть косвенным подтверждением изменения направления вращения парового вихря. Ключевые слова: тепловые трубы, направление вращения парового вихря, напряжение сдвига пленки конденсата.

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Section: результаты численного моделированияunclassified

The study of condensable vapour vortex flow in short low temperature heat pipes

Seryakov¹

2019

Journal IAR

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“…Das at al. [17] have carried out numerical simulations to investigate Coanda flow over a curved surface and analysed the application to the ACHEON system. He has observed the effect of Dielectric barrier discharge (DBD) plasma actuators, concluding that it has an effective capacity both of stabilizing the behaviour of the system and of increasing the angle of adhesion.…”

Section: Acheon Nozzle Architecturementioning

confidence: 99%

A new aircraft architecture based on the ACHEON Coanda effect nozzle: flight model and energy evaluation

Trancossi

Madonia

Dumas

et al. 2016

Eur. Transp. Res. Rev.

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Aeronautic transport has an effective necessity of reducing fuel consumption and emissions to deliver efficiency and competitiveness driven by today commercial and legislative requirements. Actual aircraft configurations scenario allows envisaging the signs of a diffused technological maturity and they seem very near their limits. This scenario clearly shows the necessity of radical innovations with particular reference to propulsion systems and to aircraftarchitecture consequently.\ud Methods\ud This paper presents analyses and discusses a promising propulsive architecture based on an innovative nozzle, which allows realizing the selective adhesion of two impinging streams to two facing jets to two facing Coanda surfaces. This propulsion system is known with the acronym ACHEON (Aerial Coanda High Efficiency Orienting Nozzle). This paper investigates how the application of an all-electric ACHEONs propulsion system to a very traditional commuter aircraft can improve its relevant performances. This paper considers the constraints imposed by current state-of-the-art electric motors, drives, storage and conversion systems in terms of both power/energy density and performance and considers two different aircraft configurations: one using battery only and one adopting a more sophisticated hybrid cogeneration. The necessity of producing a very solid analysis has forced to limit the deflection of the jet in a very conservative range (±15°) with respect to the horizontal. This range can be surely produced also by not optimal configurations and allow minimizing the use of DBD. From the study of general flight dynamics equations of the aircraft in two-dimensional form it has been possible to determine with a high level of accuracy the advantages that ACHEON brings in terms of reduced stall speed and of reduced take-off and landing distances. Additionally, it includes an effective energy analysis focusing on the efficiency and environmental advantages of the electric ACHEON based propulsion by assuming the today industrial grade high capacity batteries with a power density of 207 Wh/kg.\ud Results\ud It has been clearly demonstrated that a short flight could be possible adopting battery energy storage, and longer duration could be possible by adopting a more sophisticated cogeneration system, which is based on cogeneration from a well-known turboprop, which is mostly used in helicopter propulsion. This electric generation system can be empowered by recovering the heat and using it to increase the temperature of the jet. It is possible to transfer this considerable amount of heat to the jet by convection and direct fluid mixing. In this way, it is possible to increase the energy of the jets of an amount that allows more than recover the pressure losses in the straitening section. In this case, it is then possible to demonstrate an adequate autonomy of flight and operative range of the aircraft. The proposed architecture, which is within the limits of the most conservative results obtained, demonstrates significant additional ...

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“…ACHEON produced a large impact on the activity about modelling Coanda Effect [32][33][34], about modelling Coanda effect in presence of multiple streams [35][36][37][38][39][40][41][42][43], the potential of Dielectric Barrier Discharge [41][42][43], and application of the nozzle in aircraft propulsion, including existing aircraft architectures [44][45][46][47]. ACHEON has demonstrated very good characteristic in terms both of reduction of energy needs and take off and landing spaces equivalent to the one that can be reached by propelled wing systems.…”

Section: Figure 11 Acheon Nozzlementioning

confidence: 99%

A New Propelled Wing Aircraft Configuration

Trancossi

Stewart

Páscoa

2016

Volume 1: Advances in Aerospace Technology

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This paper investigates by an energetic approach possible new configurations of aircrafts, which can rival in low speed operations against helicopters. It starts from an effective energy balance of helicopters during fundamental operations: takeoff, horizontal flight, hovering, and landing. The energy state of a helicopter can be written as: E = ½ mV2 + mgh + ½ I ω2 (1) where m is mass of helicopter, I is total rotor inertia, ω is rotor rotational speed. By taking the partial derivative with respect to time of equation 1, the power is expressed as dE/dt = ΔP = mV dV/dt + mg dh/dt (2) By optimizing the energy balance of the helicopter a new aircraft configuration has been obtained that allow a very high lift even at very low speed, but drastically reducing the energy consumption during horizontal flight. The total power required is obtained by rotor power and overall efficiency factor (η) and HPreq total = η HPreq rotor. By equations (1) and (2) it has been produced a preliminary optimization in different operative conditions considering a speed range from 0.5 (hovering conditions) to 50 m/s. By an accurate balance of the results, it has been identified that the most disadvantageous situation for a helicopter is forward flight. A new powered wing architecture has been specifically studied for replicating the behaviour of helicopters. Preliminary it has been defined by starting from the energy equations the main characteristics of the propelled wing. From those numerical results it has been defined a new configuration of propelled wing and the new aircraft configuration which allow adequate performance against helicopter. Those wings take a large advantage of two not common features: symmetry with respect to a vertical axis and possibility of optimizing the shape for specific missions. It has been designed and optimized in different configurations by CFD. In particular, an accurate analysis of fluiddynamic of the system allows quantifying the different effects that allows realizing an extraordinary ratio between lift and thrust producing an effective vehicle that can rival against helicopter also at very low speeds with a morphing configuration that will be presented in the final paper because of patenting reasons. Results show that the proposed innovative aircraft configuration allows hovering and very low speed flight. In particular, the conditions and the design for this kind of operation are presented even if still in initial design stage. The presented aircraft architecture can also allow inverting the direction of motion just by inverting the direction of the thrust. In this case, it will allow overcoming completely the performances of helicopters. The energetic balance of flight has been evaluated and the advantages with respect to helicopters have been finally expressed with surprising results.

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Numerical modeling of coanda effect in a novel propulsive system

Cited by 18 publications

References 48 publications

The study of condensable vapour vortex flow in short low temperature heat pipes

The study of condensable vapour vortex flow in short low temperature heat pipes

A new aircraft architecture based on the ACHEON Coanda effect nozzle: flight model and energy evaluation

A New Propelled Wing Aircraft Configuration

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