Numerical and experimental study of reciprocating rod seals including surface roughness effects

Crudu, M.; Fatu, Aurelian; Hajjam, Mohamed; Cristescu, C.

doi:10.1016/s1350-4789(13)70224-1

Cited by 8 publications

(9 citation statements)

References 2 publications

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“…-The second is the inverse method that is widely used for elastomeric seals. Indeed, according to this theory, the static contact pressure "ps(x)" is assumed equal to the hydrodynamic pressure "p(x)" and the film thickness "h(x)" is computed by using the first and second derivatives of "p(x)" [4,5,6] under non-cavitation conditions.…”

Section: Introductionmentioning

confidence: 99%

“…Usually, equation ( 2) is the most used in the inverse hydrodynamic lubrication [6] to determine "h(x)" where "h * " is the film thickness at the location of the maximum pressure. The second approach is rarely used and is given by equation ( 3) with first and second derivative pressures "dp/dx" and "d 2 p/dx 2 ".…”

Section: Introductionmentioning

confidence: 99%

“…-Step 1: By using an appropriate numerical method (finite differences, finite volumes, and finite elements, analytic ...), the Reynolds equation (1) corresponding to the first analysis and modified Reynolds equation (6) for the third analysis is resolved. Thus, according to the computed pressure p(x), the lifting force W the friction force F, and the flow rate Q are deduced from equations (4).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

About the Inverse Theory and the Non-Unicity of the Film Thickness: Novel Approach Generating Equivalent Micro-Grooves and Roughness

ELGADARI

Mohamed

2021

Preprint

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Since the 1960s, all studies have assumed that a film thickness “h” provides a unique pressure field “p” by resolving the Reynolds equation. However, it is relevant to investigate the film thickness unicity under a given hydrodynamic pressure within the inverse theory. This paper presents a new approach to deduce from an initial film thickness a widespread number of thicknesses providing the same hydrodynamic pressure under a specific condition of gradient pressure. For this purpose, three steps were presented: 1) computing the hydrodynamic pressure from an initial film thickness by resolving the Reynolds equation with Gümbel’s cavitation model, 2) using a new algorithm to generate a second film thickness, 3) comparing and validating the hydrodynamic pressure produced by both thicknesses with the modified Reynolds equation. Throughout three surface finishes: the macro-shaped, micro-textured, and rough surfaces, it has been demonstrated that under a specific hydrodynamic pressure gradient, several film thicknesses could generate the same pressure field with a slight difference by considering cavitation. Besides, this paper confirms also that different ratios of the averaged film thickness by the root mean square (RMS) similar hydrodynamic pressure could be generated, thereby the deficiency of this ratio to define the lubrication regime as commonly known with Patir and Cheng theory.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

About the Inverse Theory and the Non-Unicity of the Film Thickness: Novel Approach Generating Equivalent Micro-Grooves and Roughness

ELGADARI

Mohamed

2021

Preprint

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“…Em hastes de vedação a rugosidade é um fator crítico para garantir a estanqueidade do sistema. Seu papel é fundamental para evitar o vazamento de fluidos que causariam a falha do sistema ou mesmo a contaminação do meio ambiente [3]. Na produção de rolamentos estudos consistentes comparam as propriedades da superfície (rugosidade, tensões residuais e outras) e sua relação com a vida em fadiga desses produtos [4,5].…”

Section: Introductionunclassified

Análise da rugosidade superficial de barras de aço SAE 1045 após torneamento

Biasibetti

Nunes

Cavaler³

et al. 2019

Matéria (Rio J.)

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RESUMO Neste trabalho foram investigadas as influências de alguns dos principais fatores do torneamento sobre o acabamento da superfície e a rugosidade de uma peça torneada. Foram analisadas barras de aço SAE 1045 torneadas em um torno controle numérico computadorizado (CNC), com auxílio da técnica de Planejamento de experimentos (DOE) para formar trinta e duas diferentes combinações de fatores, analisar suas interações e sua influência no acabamento de cada amostra. Os fatores de usinagem investigados foram: (1) avanço, (2) velocidade de corte, (3) raio de quina, (4) ângulo de saída e (5) região de medição da rugosidade. Por meio do DOE foram realizadas duas análises fatoriais: a primeira avaliou a influência dos cinco fatores na rugosidade média, representada por Ra, e a segunda avaliou a eficácia de cada conjunto de fatores em obter o acabamento alvo. Para isso, foi criado um índice que relaciona a rugosidade teórica de cada processo com a rugosidade medida pelo rugosímetro. Os resultados mostraram que o avanço e o raio de quina possuem elevado efeito padronizado em ambas as análises. Porém, enquanto a aplicação de um menor avanço (ou maior raio de quina) produziu superfícies com baixa Ra, por outro lado também prejudicou a eficácia do torneamento, pois contribuiu para obtenção de uma rugosidade significativamente maior que a rugosidade teórica. Já o fator velocidade de corte foi benéfico ao processo em ambas as análises. Não foi encontrada relevância da região de medição da rugosidade sobre a rugosidade média, Ra.

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“…Also, EHL characteristics of rectangular reciprocating seals have been analysed. Regarding the influence of surface roughness, Crudu et al [11] established a numerical simulation model of a reciprocating sliding seal ring, namely a ''U-shaped ring''. The calculation of friction force has been simulated and compared to test results.…”

Section: Introductionmentioning

confidence: 99%

Lubrication performance analysis of sealing structures in rodless open cylinders

Zhong

Ren

et al. 2019

Sādhanā

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As the lubrication performance of sealing structures in rodless open cylinders varies with sliding velocity, the concept of a critical velocity is proposed based on the aforementioned characteristics and the lubrication performance of sealing structure is analysed. A finite-element model of sealing structure is established and the oil film load under dynamic lubrication condition is obtained. A two-dimensional theoretical model of lubrication performance in sealing structure is established based on the proposed critical velocity. The influence on critical velocity of parameters including pre-compression, geometry size and microscopic morphology is analysed. Considering surface microscopic morphology, generation of heat by friction, heat flux distribution and other factors, a three-dimensional numerical model of lubrication performance of sealing structure is established to reveal the influence of texture mechanism on lubrication performance. As concluded, with the increase of pre-compression, the lip angle and the temperature of lubrication oil, the critical velocity increases. The three-dimensional microscopic morphology of seal ring is found to pose obvious influence on critical velocity, and the isotropic microscopic morphology tends to form total lubrication under the same conditions.

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Numerical and experimental study of reciprocating rod seals including surface roughness effects

Cited by 8 publications

References 2 publications

About the Inverse Theory and the Non-Unicity of the Film Thickness: Novel Approach Generating Equivalent Micro-Grooves and Roughness

About the Inverse Theory and the Non-Unicity of the Film Thickness: Novel Approach Generating Equivalent Micro-Grooves and Roughness

Análise da rugosidade superficial de barras de aço SAE 1045 após torneamento

Lubrication performance analysis of sealing structures in rodless open cylinders

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