Ceramic matrices applied to aerostatic porous journal bearings: material characterization and bearing modeling

Silveira, Zilda de Castro; Nicoletti, Rodrigo; Fortulan, Carlos Alberto; Purquerio, Benedito de Moraes

doi:10.1590/s0366-69132010000200016

Cited by 15 publications

(18 citation statements)

References 14 publications

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“…Pressurized air at pressure (Ps) is injected into bearing gap (h), through of the ceramic porous matrix (H) that composes the bearing casing, generating an aerostatic pressure distribution in the bearing gap. In order to calculate the aerostatic pressure distribution in the bearing gap it was developed the non-dimensional modeling by Silveira et al [6] to obtain the Reynolds's equation modified considering the viscous permeability coefficient of the porous media. This concept is presented in the Fig.…”

Section: Considerations On the Mathematical Model To Aerostatic Poroumentioning

confidence: 99%

“…Fig. 3 Fluid flow kinematics, velocity profiles, and boundary conditions in the bearing gap Source [6] This step presents the analisys of the dynamic coefficients as functions of suply and ambient pressure (Ps/Pa). The first natural freqüêncy of the aerostatic bearing (ω nb ) is obtained with the mass (m) and the normal directional stiffness (K yy ,K zz ) and it is considerably affected by the supply pressure variation as shown in the Fig.…”

Section: Dynamic Coefficients and First Natural Frequency Of The Aeromentioning

confidence: 99%

“…In the case of plated ceramics, the flow rate decreased by 1/10 or less and the clearance decreased by approximately 1/3. Silveira et al [6] presented the development of an advanced ceramic material for aerostatic porous bearing manufacturing and concluded that there is homogeneous distribution of the pores in the alumina matrix by using different concentrations of the added component (sucrose). The average pore diameter remained around 0.14 microns and respective porosity around 28 %, with small standard deviation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Static and Dynamic Analyses of a Rotor with Aerostatic Ceramic Porous Journal

Chiarelli

Silveira

2015

Proceedings of the 9th IFToMM International Conference on Rotor Dynamics

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This work presents the numerical model of an experimental set-up where it was made an evaluation on the static characteristics of the shaft and the identification of the dynamic characteristics for an aerostatic radial porous bearing. The use of ceramic porous as journal for aerostatic bearings can improve its perform related to the wear, thermal stability, stiffness and load capacity allowing that spindles work with precision at speed above 20,000 rpm with small clearances (40 μ). In order to investigate these bearings were developed static analyses to obtain the deflection and stiffness of the support shaft, stiffness of the aerostatic porous bearing and dynamic identification for experimental set-up. The static analysis indicated stiffness of shaft and aerostatic porous bearing of 20.1 and 2.6 kN/mm, respectively. The dynamic analysis indicated that the first natural frequency of the rotor is close to 1365.9 Hz, which is much higher than the first natural frequency of the aerostatic ceramic porous bearing whose value is 775.0 Hz. One can concluded that geometrical configuration and support conditions choosen allow a robust condition to proceed the experimental tests in order to obtain dynamic characteristic of the aerostatic porous bearing.

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Section: Considerations On the Mathematical Model To Aerostatic Poroumentioning

confidence: 99%

Section: Dynamic Coefficients and First Natural Frequency Of The Aeromentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Static and Dynamic Analyses of a Rotor with Aerostatic Ceramic Porous Journal

Chiarelli

Silveira

2015

Proceedings of the 9th IFToMM International Conference on Rotor Dynamics

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“…The availability of a porous material with predictable fluid flow characteristics has been the main challenge to the successful application of porous bearings (Figure 1). 7 To date, most porous aerostatic bearings have been based on sintered carbon, 8 silicon carbide, 2 bronze, sintered alumina 6,[9][10][11][12] or graphite materials. 3,13,14 Panzera et al 15,16 have investigated a set of compacted cementitious composites, using water-to-cement ratio of 0.25, for application as an air restrictor in aerostatic thrust bearings.…”

Section: Introductionmentioning

confidence: 99%

Carbon nanotubes and superplasticizer reinforcing cementitious composite for aerostatic porous bearing

Silva

Panzera

Vieira

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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Cementitious composites are low cost and readily manufactured materials which can be used for specialist applications such as the production of aerostatic porous bearings. A design of experiment was used to identify the effects of superplasticizer additions and carbon nanotube inclusions on the physical and mechanical properties of cementitious composites which can be applied as porous restrictor in aerostatic thrust bearings. The presence of carbon nanotubes was able to increase the bulk density, the compressive strength and the modulus of elasticity, and also decrease the apparent porosity of the composites. The composite made with 0.4 wt.% of superplasticizer and 0.05 wt.% of carbon nanotubes achieved acceptable properties for the use as double-layered porous restrictor in aerostatic thrust bearings.

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“…Nestes trabalhos, a pressão praticada nas membranas, geralmente de forma tubular, era limitada pela espessura do tubo que, em um módulo multitubular, não permite projetos compactos que são altamente desejáveis. (DEL COLLE, 2010;HANEDA, 2010;FORTULAN et al, 2006;SILVEIRA et al, 2010). 2007;KHEMAKHEM et al, 2009;MASMOUDI et al, 2006.…”

Section: Como Referência Foram Utilizados Trabalhos Anteriores Do Gruunclassified

Projeto e caracterização de membranas cerâmicas utilizando microfibras como precursoras de porosidade

Prado¹

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Agradeço a Deus pelo dom da vida, por orientar meus passos, me amparar nos momentos difíceis e me dar a força para seguir sempre em frente. Agradeço aos meus pais, Sebastião e Maria, pelo amor, carinho, apoio e incentivo em todos os momentos da minha vida. Às minhas irmãs, Janaina e Jaqueline, pelo amor, carinho e companheirismo, frutos do alicerce construído pelos nossos pais. Ao Ricardo, meu esposo, pelo amor, paciência, apoio e companheirismo. À minha filha, Ana Letícia, por cada abraço e cada sorriso. O nosso amor é o recanto de paz que o meu coração sempre encontra. À minha amiga Camila, minha irmã de coração, por todo incentivo, apoio e contribuições na realização deste trabalho, mas, sobretudo, pela nossa amizade. Obrigada pelo carinho e cumplicidade em todos os momentos da minha vida. Ao Prof. Dr. Carlos Alberto Fortulan pela oportunidade, orientação, dedicação e apoio no decorrer de todo o trabalho. Agradeço também por todo incentivo, paciência e amizade. Ao Prof. Associado Rafael Salomão-SMM/EESC/USP, por disponibilizar as fibras de polipropileno e de álcool polivinílico e pelas discussões acerca delas. À todos os colegas do Laboratório de Tribologia e Compósitos, em especial ao Luiz Adalberto Penazzi, técnico do LTC, por todo suporte, disposição e amizade. À empresa Critéria, Indústria e Comércio de Produtos Medicinais e Odontológicos Ltda. pela liberação do período necessário para a realização das atividades deste trabalho, em especial ao Dr. Francisco José Correa Braga pelo apoio e incentivo para nunca parar os estudos.

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Ceramic matrices applied to aerostatic porous journal bearings: material characterization and bearing modeling

Cited by 15 publications

References 14 publications

Static and Dynamic Analyses of a Rotor with Aerostatic Ceramic Porous Journal

Static and Dynamic Analyses of a Rotor with Aerostatic Ceramic Porous Journal

Carbon nanotubes and superplasticizer reinforcing cementitious composite for aerostatic porous bearing

Projeto e caracterização de membranas cerâmicas utilizando microfibras como precursoras de porosidade

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