This thesis work is based on the analysis of a fan blade attachment whereby a complete 3D model is presented by a partner company. The acceptability of a new design regarding the mechanical loads consisting of dividing the hub into two parts instead of using a solid hub is studied. From the model some critical parameters for the attachment of the blade with respect to the stresses are chosen such as the rotational speed, fillet size of the blade and the neck size of the blade. Parametric studies of these parameters are carried out in order to suggest the new design. Bearing in mind that a safety factor of 2 is the prerequisite, based on the analysis performed on ANSYS Workbench, it is suggested from the preliminary design that the axial fan can operate in two specific scenarios consisting of a rotational speed of 1771 rpm and a rotational speed of 1594 rpm. Using this set of parameters, a suggestion is drawn up on the blade fillet which will give lower stress. Blade fillet size of 30 to 35mm is recommended while a size of 45mm is recommended on the neck of the blade. A modal analysis is performed in order to find at what frequency will the model be vibrating and a lowest and critical frequency of 16.8 Hz is obtained. Finally, a fatigue analysis of some interesting areas is performed in order to determine the numbers of cycles before fatigue failure occur. It is recommended to use the rotational speed since these speeds have offered a High Cycle Fatigue results.

A new active-passive approach for the control of noise radiated from a small axial fan was investigated. The approach involved the installation of an axial fan into a short duct with both passive and active noise control functions. First, a systematic methodology for the analytical modeling of finite-length ducts with multiple discontinuities was formulated. The procedure involved the modeling of a duct as a collection of simple duct sections, which were interconnected at multiple junctions. Analytical studies have shown that a short lined duct provides passive noise reduction effects through the mass-loading effect of the duct air volume at low frequencies and the sound absorption by a passive liner at high frequencies. It was also shown that active control can provide further noise attenuations at low-to-mid frequencies, thereby enhancing the overall noise control performance. Two alternate designs of active-passive noise control fan duct were considered. One was a simple non- segmented duct with a 2x2 active control and the other was an internally segmented duct with an 8x8 active control. It was indicated that the latter design possesses a significantly higher global noise control potential than the former with respect to both bandwidth and attenuation level. This was attributed to the reduction of the unwanted pressure contributions from the duct cross modes through the high frequency shifting of the associated cut-on frequencies. The experimental validation of the noise control approach was also carried out. An active-passive noise control fan duct incorporating the segmented duct design with 8x8 active control was constructed in conjunction with a hybrid feedforward-feedback control system. Experimental results have shown significant reductions in the total fan noise power associated with the first four BPF tones by the feedforward control and the broadband fan noise power by the feedback control. The overall active-passive noise control characteristics were observed to be in accordance with the analytical results. / Ph. D.

Nous avons abordé dans ce travail deux aspects particuliers de la mécanique des fluides appliquées à la conception des matériels de lutte contre l’incendie. Le premier concerne la ventilation lors du traitement des compartiments. Nous avons montré qu’une grille alvéolaire, placée devant l’hélice du ventilateur, nous permet de façonner le jet et de lui donner une forme ovalisée. Cette forme est plus adéquate à l’entrant du compartiment et permet un gain important de la performance de ces ventilateurs. Le deuxième aspect de ce travail a été de concevoir un système de dosage d’émulseur dans un réseau d’eau sous pression. Nous avons pour cela défini un doseur de type venturi, équipé d’une ogive conique au niveau du col. Cette ogive, dont la position est définie par le rapport entre la pression d’entrée et la pression de sortie. Nous avons montré, à partir du théorème de Bernoulli, que ce système permet de maintenir une aspiration au niveau du col, quelle que soit la pression ou le débit le traversant. / In this work we have analysed two topics of fluid mechanics, applied to the design of fire fighting equipment. The first one is the performance of ventilation during the movement of air in a compartment that contains a fire. We have shown that specific blade angle designed within the gril and placed in front of the fan propeller, allows us to manipulate the jet of air giving it an oval shape. This shape is more efficient and allows a significant gain in the air movement performance within the compartment for these fans. The second aspect of this work was to define an emulsifier dosing system in a pressurized water system. We define a venturi dosing system with a movable cone piece. The position of this conical piece is Controlled by the pressure ratio between the inlet and the outlet. Based on Bernoulli's theorem, we have demontrated that this system maintains a level of suction at the Inlet regardless of the pressure or flow passing through it.

<p>Fans are often used in equipment such as home appliances andelectronic equipment where the margin of profit is small butcustomers demands on a low noise level are high. Therefore,methods for predicting the noise emitted by an applicationincluding one or several fans are desirable in order toimprove, accelerate and reduce the cost of low-noise design.The Noise Shaping Technology (NST) has been developed withinthe EC-project NABUCCO in order to fulfil the aboverequirements on a prediction method. According to NST, thenoise source (not necessary a fan) is described by one orseveral noise descriptors, CSSs, and the correspondingtransmission paths through the structure described by one orseveral transfer functions, ACFs. In this thesis, theapplicability of NST is evaluated on a cabinet for electronicequipment where small axial cooling fans constitute the primarysources of the airborne sound.</p><p>As an axial fan is a complex source of sound,simplifications are necessary when modelling its acousticproperties. Therefore, the sound radiation of an axial fan infree space was examined by expanding the generated soundpressure field into spherical harmonics. The conclusion on asource model for the cabinet example, where the fans are moreor less In-duct mounted, is a modified single axial dipole. Themodel is expected to be valid in the entire frequency range ofinterest except in the mid-frequency range where the modaldensity is low. In order to improve the source model in thisfrequency range, a future model based on a rotating dipole isproposed.</p><p>The sound power of a small axial fan is measured in an ISO10302 test-rig. In order to take account of flow conditions,acoustically transparent ducts have been developed. These shallbe attached to the test-rig when measuring the sound power ofthe fan. A simple but practical method of how to correct thesound power for the baffling effect of the test-rig has alsobeen developed. Finally, the sound power can be converted intodipole force, which is the airborne CSS corresponding to thesingle axial dipole model.</p><p>The corresponding airborne transfer function (ACF), i.e.,from dipole force at the source point to sound pressure at thereceiver point, is measured reciprocally by taking use ofLyamshevs reciprocity relation.</p><p>From multiplication of the CSS and the ACF, the soundpressure can be predicted. The prediction shows quite goodagreement with the measured values.</p><p><b>Keywords:</b>axial fan, airborne sound, sourcecharacterisation, transmission path analysis, In-duct,spherical harmonics, rotating dipole, installation effects, ISO10302, flow conditions, baffling effect, acousticallytransparent ducts, Lyamshevs reciprocity relation, reciprocity,CSS, ACF, GSM, NST.</p>

Fans are often used in equipment such as home appliances andelectronic equipment where the margin of profit is small butcustomers demands on a low noise level are high. Therefore,methods for predicting the noise emitted by an applicationincluding one or several fans are desirable in order toimprove, accelerate and reduce the cost of low-noise design.The Noise Shaping Technology (NST) has been developed withinthe EC-project NABUCCO in order to fulfil the aboverequirements on a prediction method. According to NST, thenoise source (not necessary a fan) is described by one orseveral noise descriptors, CSSs, and the correspondingtransmission paths through the structure described by one orseveral transfer functions, ACFs. In this thesis, theapplicability of NST is evaluated on a cabinet for electronicequipment where small axial cooling fans constitute the primarysources of the airborne sound. As an axial fan is a complex source of sound,simplifications are necessary when modelling its acousticproperties. Therefore, the sound radiation of an axial fan infree space was examined by expanding the generated soundpressure field into spherical harmonics. The conclusion on asource model for the cabinet example, where the fans are moreor less In-duct mounted, is a modified single axial dipole. Themodel is expected to be valid in the entire frequency range ofinterest except in the mid-frequency range where the modaldensity is low. In order to improve the source model in thisfrequency range, a future model based on a rotating dipole isproposed. The sound power of a small axial fan is measured in an ISO10302 test-rig. In order to take account of flow conditions,acoustically transparent ducts have been developed. These shallbe attached to the test-rig when measuring the sound power ofthe fan. A simple but practical method of how to correct thesound power for the baffling effect of the test-rig has alsobeen developed. Finally, the sound power can be converted intodipole force, which is the airborne CSS corresponding to thesingle axial dipole model. The corresponding airborne transfer function (ACF), i.e.,from dipole force at the source point to sound pressure at thereceiver point, is measured reciprocally by taking use ofLyamshevs reciprocity relation. From multiplication of the CSS and the ACF, the soundpressure can be predicted. The prediction shows quite goodagreement with the measured values. <b>Keywords:</b>axial fan, airborne sound, sourcecharacterisation, transmission path analysis, In-duct,spherical harmonics, rotating dipole, installation effects, ISO10302, flow conditions, baffling effect, acousticallytransparent ducts, Lyamshevs reciprocity relation, reciprocity,CSS, ACF, GSM, NST. / NR 20140805

Aujourd’hui, la fabrication des turbomachines est conditionnée par des normes de plus en plus restrictives. L'enjeu industriel pour les chercheurs est d'envisager des solutions optimales visant à réduire les sources de perte d'énergie, d'instabilité et du bruit, en particulier l'écoulement de jeu (débit de fuite). Des actions préliminaires ont été élaborées à Arts & Métiers ParisTech sur le rotomoulage du ventilateur axial de refroidissement d'automobile. L'idée de ce travail est d'utiliser la forme creuse induite par le rotomoulage afin de l'exploiter dans le controle de l'écoulement de jeu radial par soufflage rotatif. Pour cela, la virole comporte des trous d'injection orientés de façon à réduire simultanément le débit de fuite et le couple. Dans ce travail, trois parties ont été traité. La première concerne la réalisation du ventilateur par rotomoulage. La deuxième concerne l'étude expérimentale menée dans le banc d'essai ISO 5801. Cette étude comporte la réalisation d'un montage dédié au contrôle par soufflage rotatif, la métrologie menée pour la détermination des performances globales et la caractérisation de la vitesse axiale du sillage proche. La troisième partie traite la modélisation numérique des conditions expérimentales rentables ensuite l'extrapolation du travail vers des taux d'injection importants. Pour ce dernier, on arrive à annuler le débit de fuite avec un gain considérable du couple mettant ainsi le ventilateur en autorotation. / Nowadays, the manufacture of turbomachinery is conditioned by more and more restrictive rules. The industrial challenge for researchers has to consider optimal solutions to reduce sources of energy loss, instability and noise, particularly the tip clearance flow (leakage flow rate). Preliminary actions have been developed at Arts & ParisTech on rotational molding process used for the automobile cooling axial fan. The idea of this work is to use the hollow shape induced by rotational molding process in order to exploit it in the control of tip clearance flow through rotary steady air injection. For this, the shroud ring is composed of injection holes oriented in such away to reduce both of leakage flow rate and the torque. In this work, the thesis focuses on three parts. The first concerns the build of the fan by rotational molding process. The second concerns the experimental study carried out in the ISO 5801 test bench. This study involves the realization of drive system dedicated to rotary steady air injection, metrology for performance determination and the characterization of the near wake axial velocity. The third part deals with the numerical modeling of efficient experimental conditions, then the extrapolation of work towards high injection rates. For this latter, it is possible to cancel leakage flow rate with a considerable gain of the torque thus putting the fan in autorotation.

This Master thesis solves a construction development of alternative modular mechanical systems for ventilation turbines. A research part of the thesis deals with the issues of transported medium (air) and ventilation, as well as functions, designs of ventilation turbines, and finally it provides an overview of ventilation turbines produced by manufacturers worldwide; these are used for ventilation of residential, commercial, industrial or agricultural structures using the natural or hybrid ventilation. A construction - design part is focused on creating 3D models of selected alternative modular adjustable ventilation turbines according to the data provided by the thesis supervisor and then on establishing a system for calculating the shapes of blades relative to the airflow for additional axial fan of ventilation turbines. For this purpose, a customized software application VENTILATOR (GUI) was developed to allow a flexible change of input calculation parameters and thus a fast modification of the curve shape in the 3D model of the axial fan blade.

Orientador: Alcides Padilha / Banca: Ivan De Domenico Valarelli / Banca: Kamal Abdel Radi Ismail / Resumo: Neste trabalho apresenta-se uma análise teórica e experimental dos resultados comparativos entre as curvas características de um ventilador axial utilizado em um sistema de pulverização agrícola para um ângulo de ataque da pá em 32 graus nas rotações de 1500, 1750, 2600 e 3000 rpm e resultados numéricos da influência da variação do ângulo de ataque da pá em 28, 32 e 36 graus e da otimização do sistema de pulverização ambos para uma rotaç]ao de 2600 rpm. O campo médio turbulento foi obtido com a aplicação da média temporal sendo que o modelo de turbulência exigido para o fechamento do conjunto de equações foi o modelo k-ε de duas equações. A resolução de todos os fenômenos acoplados foi alcançada com o auxílio do código de fluidodinâmica computacional CFX que utiliza a técnica dos volumes finitos como método numérico. Para validação da análise teórica, realizaram-se experimentos em um túnel de vento horizontal de seção circular com diâmetro de 622 mm, usando um tubo de Pitot para as tomadas de pressão de acordo com a norma para ensaios em laboratório. Apresentam-se resultados qualitativos na forma de vetores e mapas de gradiente de velocidade e, quantitativos na forma de tabelas e gráficos para as curvas características. / Abstract: This paper presents a theoretical and experimental analysis of comparative results the characteristic curves of an axial fan used in an agricultural spraying system for a blade attack angle of 32 degrees at rotations of 1500, 1750, 2600 and 3000 rpm and numerical results for the influence of blade attack angle variation at 28, 32 and 36 degrees and optimization of the spraying system, both for a rotation of 2600 rpm. The average turbulent field was obtained from the application of time average where the turbulence model required for closing the set of equations was the k-ε model for two equations. Resolution of all connected phenomena was achieved with the help of the fluid dynamics computacional, CFX, which uses the finite volumes technique as a numerical method. In order to validate the theoretical analysis, an experiment was conducted in a circular section of a horizontal wind tunnel, 622 mm in diameter and 6220 mm in length, using a Pitot tube for pressure readings according to the norm for laboratory assays. Qualitative results are shown as vectors and gradient maps for speed and quantitative results are shown in tables and graphics for characteristic curves. / Mestre

Made available in DSpace on 2014-06-11T19:25:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-06Bitstream added on 2014-06-13T18:26:31Z : No. of bitstreams: 1 fogal_mlf_me_bauru.pdf: 1973940 bytes, checksum: 7fa4d89826d2cfb9214807f1ec353036 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho apresenta-se uma análise teórica e experimental dos resultados comparativos entre as curvas características de um ventilador axial utilizado em um sistema de pulverização agrícola para um ângulo de ataque da pá em 32 graus nas rotações de 1500, 1750, 2600 e 3000 rpm e resultados numéricos da influência da variação do ângulo de ataque da pá em 28, 32 e 36 graus e da otimização do sistema de pulverização ambos para uma rotaç]ao de 2600 rpm. O campo médio turbulento foi obtido com a aplicação da média temporal sendo que o modelo de turbulência exigido para o fechamento do conjunto de equações foi o modelo k-ε de duas equações. A resolução de todos os fenômenos acoplados foi alcançada com o auxílio do código de fluidodinâmica computacional CFX que utiliza a técnica dos volumes finitos como método numérico. Para validação da análise teórica, realizaram-se experimentos em um túnel de vento horizontal de seção circular com diâmetro de 622 mm, usando um tubo de Pitot para as tomadas de pressão de acordo com a norma para ensaios em laboratório. Apresentam-se resultados qualitativos na forma de vetores e mapas de gradiente de velocidade e, quantitativos na forma de tabelas e gráficos para as curvas características. / This paper presents a theoretical and experimental analysis of comparative results the characteristic curves of an axial fan used in an agricultural spraying system for a blade attack angle of 32 degrees at rotations of 1500, 1750, 2600 and 3000 rpm and numerical results for the influence of blade attack angle variation at 28, 32 and 36 degrees and optimization of the spraying system, both for a rotation of 2600 rpm. The average turbulent field was obtained from the application of time average where the turbulence model required for closing the set of equations was the k-ε model for two equations. Resolution of all connected phenomena was achieved with the help of the fluid dynamics computacional, CFX, which uses the finite volumes technique as a numerical method. In order to validate the theoretical analysis, an experiment was conducted in a circular section of a horizontal wind tunnel, 622 mm in diameter and 6220 mm in length, using a Pitot tube for pressure readings according to the norm for laboratory assays. Qualitative results are shown as vectors and gradient maps for speed and quantitative results are shown in tables and graphics for characteristic curves.

RESUME : Les machines axiales à rotors contrarotatifs subsoniques sont une bonne solution pour les industries où de fortes élévations de pressions et d'efficacités sont nécessaires sans augmenter le diamètre ou la vitesse de rotation des rotors. Néanmoins, le comportement des CRS et les paramètres impactant ses performances ne sont pas encore totalement compris. Cette thèse mène une investigation expérimentale sur la performance et les paramètres influents sur un étage contrarotatif. La technique de design et les méthodes de mesure sont repris sur une thèse précédente réalisée au laboratoire Dynfluid (Arts et métiers ParisTech). Trois étages contrarotatifs ont été fabriqués (JW1, JW2 et JW3) et testés sur le banc d'essai normalisé AERO2FANS. Ces machines ont été conçues pour avoir le même point de fonctionnement mais avec une répartition de charge différente. Les résultats expérimentaux se concentrent dans un premier temps sur JW1. Les grandeurs physiques regardées sont l'efficacité globale et l'élévation de pression statique pour juger de la performance globale de la machine. La fluctuation de pression pariétale et le champ de vitesse sont aussi mesurés. L'impact du changement de rapport de vitesse ou la distance entre les deux rotors sur la machine JW1 a été étudiée grâce aux grandeurs physiques décrits précédemment. Enfin dans une dernière partie, les trois machines sont comparées toujours grâce aux grandeurs physiques définies précédemment. / ABSTRACT : The counter rotating subsonic axial flow fans could be a good solution for applications where the highly improved static pressure and efficiency are required without the increase of rotational speed and fan diameter. However, the mechanisms of high performance CRS and parameters influences are not well understood nowadays. This thesis is an experimental investigation of the performance and parameter studies of two counter rotatingaxial flow ducted fans. The design and measurement methods are based on the previous research work in Laboratory Dynfluid (Arts et Métiers ParisTech). Three Counter Rotating Stages (CRS) (named JW1, JW2 and JW3) are developed and tested on a normalized test bench (AERO2FANS). These systems have same design point and differ by the distribution of loading as well as the ratio of angular velocity between the Front Rotor (FR) and Rear Rotor (RR). The first part of results focus on the JW1. The overall performance is obtained by the experimental results of the static pressure rise and static efficiency, as well as the wall pressure fluctuations recorded by a microphone on the casing wall. The parameter study is conducted to investigate the effects of the axial distance and the ratio of angular velocity between the FR and RR on the global performance and flow fields measured by Laser Doppler Velocimetry (LDV).The last part of the work is devoted to analyze the differences of the three CRS with different distribution of work, in terms of the global performance and flow features.