Performance improvement of a compound helicopter rotor head by aerodynamic design optimisation of a blade-sleeve fairing

2019 ◽  
Vol 123 (1268) ◽  
pp. 1456-1475
Author(s):  
P. Pölzlbauer ◽  
C. Breitsamter ◽  
D. Desvigne

ABSTRACTWithin the present publication, the rotor head of a compound helicopter known as Rapid And Cost-Effective Rotorcraft (RACER) is investigated. In particular, the aerodynamic design optimisation of the RACER blade-sleeve fairings (BSFs) is conducted. For this purpose, an isolated rotor head is generated featuring a full-fairing beanie, the BSF and a truncated rotor blade (RB). Moreover, a single RB is investigated at two different azimuthal rotor positions, which correspond to the advancing and the retreating RB case. For this purpose, an averaged circumferential velocity is determined in the blade-sleeve region and superposed with the RACER cruise speed in order to estimate the prevailing flow conditions. The automated aerodynamic design optimisation is performed by means of a previously developed optimisation tool chain. A global multi-objective genetic optimisation algorithm is applied for the given problem. During preliminary work, a 2D aerodynamic design optimisation of selected blade-sleeve sections was conducted. These optimised aerofoils represent the design variables for the current optimisation problem. The shape modification of the 3D fairing is realised by exchanging specific aerofoils at certain spanwise sections.

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 66
Author(s):  
Patrick Pölzlbauer ◽  
Andreas Kümmel ◽  
Damien Desvigne ◽  
Christian Breitsamter

The present work is part of the Clean Sky 2 project Full-Fairing Rotor Head Aerodynamic Design Optimization (FURADO), which deals with the aerodynamic design optimization of a full-fairing rotor head for the Rapid And Cost-Effective Rotorcraft (RACER) compound helicopter. The rotor head is a major drag source and previous investigations have revealed that the application of rotor head fairings can be an effective drag reduction measure. As part of the full-fairing concept, a new blade-sleeve fairing was aerodynamically optimized for cruise flight. Within this publication, the newly developed blade-sleeve fairing is put to test on an isolated, five-bladed rotor head and compared to an already existing reference blade-sleeve fairing, which was developed at Airbus Helicopters. Numerical flow simulations are performed with ANSYS Fluent 2019 R2 considering a rotating rotor head with cyclic pitch movement. The aerodynamic forces of the isolated rotor head are analyzed to determine the performance benefit of the newly developed blade-sleeve fairing. A drag reduction of 4.7% and a lift increase of 20% are obtained in comparison to the Airbus Helicopters reference configuration. Furthermore, selected surface and flow field quantities are presented to give an overview on the occurring flow phenomena.


Author(s):  
Rama Subba Reddy Gorla

Heat transfer from a nuclear fuel rod bumper support was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall heat transfer rates due to the thermodynamic random variables. These results can be used to identify quickly the most critical design variables in order to optimize the design and to make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in heat transfer and to the identification of both the most critical measurements and the parameters.


Author(s):  
Andrea Milli ◽  
Olivier Bron

The present paper deals with the redesign of cyclic variation of a set of fan outlet guide vanes by means of high-fidelity full-annulus CFD. The necessity for the aerodynamic redesign originated from a change to the original project requirement, when the customer requested an increase in specific thrust above the original engine specification. The main objectives of this paper are: 1) make use of 3D CFD simulations to accurately model the flow field and identify high-loss regions; 2) elaborate an effective optimisation strategy using engineering judgement in order to define realistic objectives, constraints and design variables; 3) emphasise the importance of parametric geometry modelling and meshing for automatic design optimisation of complex turbomachinery configurations; 4) illustrate that the combination of advanced optimisation algorithms and aerodynamic expertise can lead to successful optimisations of complex turbomachinery components within practical time and costs constrains. The current design optimisation exercise was carried out using an in-house set of software tools to mesh, resolve, analyse and optimise turbomachinery components by means of Reynolds-averaged Navier-Stokes simulations. The original configuration was analysed using the 3D CFD model and thereafter assessed against experimental data and flow visualisations. The main objective of this phase was to acquire a deep insight of the aerodynamics and the loss mechanisms. This was important to appropriately limit the design scope and to drive the optimisation in the desirable direction with a limited number of design variables. A mesh sensitivity study was performed in order to minimise computational costs. Partially converged CFD solutions with restart and response surface models were used to speed up the optimisation loop. Finally, the single-point optimised circumferential stagger pattern was manually adjusted to increase the robustness of the design at other flight operating conditions. Overall, the optimisation resulted in a major loss reduction and increased operating range. Most important, it provided the project with an alternative and improved design within the time schedule requested and demonstrated that CFD tools can be used effectively not only for the analysis but also to provide new design solutions as a matter of routine even for very complex geometry configurations.


Author(s):  
S. V. Subramanian ◽  
R. Bozzola ◽  
Louis A. Povinelli

The performance of a three dimensional computer code developed for predicting the flowfield in stationary and rotating turbomachinery blade rows is described in this study. The four stage Runge-Kutta numerical integration scheme is used for solving the governing flow equations and yields solution to the full, three dimensional, unsteady Euler equations in cylindrical coordinates. This method is fully explicit and uses the finite volume, time marching procedure. In order to demonstrate the accuracy and efficiency of the code, steady solutions were obtained for several cascade geometries under widely varying flow conditions. Computed flowfield results are presented for a fully subsonic turbine stator and a low aspect ratio, transonic compressor rotor blade under maximum flow and peak efficiency design conditions. Comparisons with Laser Anemometer measurements and other numerical predictions are also provided to illustrate that the present method predicts important flow features with good accuracy and can be used for cost effective aerodynamic design studies.


Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2207
Author(s):  
Lea Dujić Rodić ◽  
Toni Perković ◽  
Tomislav Županović ◽  
Petar Šolić

In order to detect the vehicle presence in parking slots, different approaches have been utilized, which range from image recognition to sensing via detection nodes. The last one is usually based on getting the presence data from one or more sensors (commonly magnetic or IR-based), controlled and processed by a micro-controller that sends the data through radio interface. Consequently, given nodes have multiple components, adequate software is required for its control and state-machine to communicate its status to the receiver. This paper presents an alternative, cost-effective beacon-based mechanism for sensing the vehicle presence. It is based on the well-known effect that, once the metallic obstacle (i.e., vehicle) is on top of the sensing node, the signal strength will be attenuated, while the same shall be recognized at the receiver side. Therefore, the signal strength change conveys the information regarding the presence. Algorithms processing signal strength change at the receiver side to estimate the presence are required due to the stochastic nature of signal strength parameters. In order to prove the concept, experimental setup based on LoRa-based parking sensors was used to gather occupancy/signal strength data. In order to extract the information of presence, the Hidden Markov Model (HMM) was employed with accuracy of up to 96%, while the Neural Network (NN) approach reaches an accuracy of up to 97%. The given approach reduces the costs of the sensor production by at least 50%.


2021 ◽  
Author(s):  
Ranjan Das

Abstract The present article highlights the implementation of differential evolution (DE)-assisted metaheuristic optimizer to provide the solution of an inverse multi-variable problem related to a flat absorber solar collector consisting of a single glass. For satisfying a given heating requirement from the solar collector, the necessary tilt angle and the thickness of the glass cover are simultaneously predicted using the proposed DE methodology. The existing study of inverse multi-variable optimization analysis has been done for dynamic values of solar energy radiation and different ambient conditions commonly encountered in various geographical locations of India. Formulation of the current research involves the minimization of a newly proposed cost function involving the required and the acquired heat transfer rates from the solar collector in Euclidean space. The solution approach then utilizes a dynamic exchange between evolutionary metaheuristic DE and a well-validated forward solver containing analytical expressions of heat energy balance within the solar collector. Variations of cost function and the estimated design variables are mainly studied to visualize the algorithm’s behavior for a single gazing-based solar thermal device. Multiple possible groupings of the unknown parameters of the solar collector are revealed, which always collectively result in a desired heating requirement from the solar collector. Sensitivity indices related to the design variables are evaluated for ascertaining the relative importance of parameter selection. Encouraging opportunity is found towards the system’s size reduction through sparing selection of inclination angle. The current study provides a convenient and cost-effective tool to select the necessary inclination and glass covers to obtain low to medium heating requirements from the available incident solar energy.


Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1855 ◽  
Author(s):  
Varvara Mytilinou ◽  
Estivaliz Lozano-Minguez ◽  
Athanasios Kolios

This research develops a framework to assist wind energy developers to select the optimum deployment site of a wind farm by considering the Round 3 available zones in the UK. The framework includes optimization techniques, decision-making methods and experts’ input in order to support investment decisions. Further, techno-economic evaluation, life cycle costing (LCC) and physical aspects for each location are considered along with experts’ opinions to provide deeper insight into the decision-making process. A process on the criteria selection is also presented and seven conflicting criteria are being considered for implementation in the technique for the order of preference by similarity to the ideal solution (TOPSIS) method in order to suggest the optimum location that was produced by the nondominated sorting genetic algorithm (NSGAII). For the given inputs, Seagreen Alpha, near the Isle of May, was found to be the most probable solution, followed by Moray Firth Eastern Development Area 1, near Wick, which demonstrates by example the effectiveness of the newly introduced framework that is also transferable and generic. The outcomes are expected to help stakeholders and decision makers to make better informed and cost-effective decisions under uncertainty when investing in offshore wind energy in the UK.


2017 ◽  
Vol 7 (2) ◽  
pp. 340-348 ◽  
Author(s):  
M. Domini ◽  
G. Langergraber ◽  
L. Rondi ◽  
S. Sorlini ◽  
S. Maswaga

The Sanitation Safety Planning methodology is implemented within a cooperation project in Iringa, Tanzania. The study presents the methodology and its adaptation and use for the given context, in order to assess risks and to support stakeholders in improving the current sanitation system and validate the design of an improved one. First results of the application of the methodology, obtained in one of the four peri-urban wards of Iringa, demonstrated its efficacy and utility in prioritising risks and identifying cost-effective control measures. Risks were assessed by the use of a semi-quantitative approach, and a simplified risk assessment matrix was developed for the case study. A sensitivity analysis was carried out in order to evaluate criteria for prioritising control measures to be selected for the development of an achievable improvement plan.


2020 ◽  
Vol 10 (10) ◽  
pp. 3438
Author(s):  
Benjamin Zenker ◽  
Martin Dannemann ◽  
Sirko Geller ◽  
Klaudiusz Holeczek ◽  
Oliver Weißenborn ◽  
...  

In the present study, it could be shown that by integration of a piezoceramic transducer in a fiber-reinforced door side panel, a flat loudspeaker can be realized. Taking into account the given restrictions, the integration position has been identified, where the geometry decouples the vibrating membrane from the supporting surface. With the help of an acoustic finite-element simulation, the main design variables of the integration position were found and the relevant effects for sound radiation were made visible. The manufacturing of the test specimen with piezoceramic transducers was performed using vacuum-assisted resin infusion and the long fiber injection procedure. The effect on the real sound radiation behavior of the door side panel with a material-immanent loudspeaker was experimentally determined using laser scanning vibrometry and sound pressure measurements. The presented work shows, for the first time, the high potential of acoustic functionalization of lightweight structures during the manufacturing process for the realization of lightweight and space-saving loudspeakers in a production-ready process.


Author(s):  
Lakshay Khera ◽  
Niraj Kumar ◽  
Ambrish Maurya

Currently demand of Indian budget cars also called people’s car in India is in great demand and around 1 million cars have been sold in the last financial year with 12% increase of sales in every forthcoming year. These are categorized in sub 4m category of sedan, hatchbacks and medium size SUVs’ and their price ranges between 7 to 11 lakhs. The aerodynamics significantly affects the performance of the vehicle particularly at high speed. The manufactures are more focused on styling and giving a luxury look and other features of the car which sometimes make them to compromise on its aerodynamic design. This may lead to increase in fuel consumption at Indian road conditions. A cost-effective way to reduce fuel consumption, drag coefficient, lift force is to improve aerodynamic behavior and reduce the aerodynamic drag. The software used in this work is Solidworks, Ansys Fluent and commercial CFD post. Consequently, of using this software, it allows us to apply, learn and link technical knowledge of aerodynamics and computer knowledge.


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