Unsteady friction model modified with compression–expansion effects in transient pipe flow
This paper aims to modify the conventional one-coefficient instantaneous acceleration-based (IAB) model for better prediction of unsteady friction behavior. In this work, the energy dissipation caused by viscous stress during fluid volume compression–expansion (CE) was derived from the compressible...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IWA Publishing
2022-02-01
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| Series: | Aqua |
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| Online Access: | http://aqua.iwaponline.com/content/71/2/330 |
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| author | Z. Cao Z. Wang J. Deng X. Guo L. Lu |
| author_facet | Z. Cao Z. Wang J. Deng X. Guo L. Lu |
| author_sort | Z. Cao |
| collection | DOAJ |
| description | This paper aims to modify the conventional one-coefficient instantaneous acceleration-based (IAB) model for better prediction of unsteady friction behavior. In this work, the energy dissipation caused by viscous stress during fluid volume compression–expansion (CE) was derived from the compressible Navier–Stokes equation. It is found that the energy dissipation term can be expressed by the product of the second-order partial derivative of velocity in space and the second viscosity coefficient. On this basis, a modified IAB-CE model was developed with the energy dissipation term and solved by the method of characteristic (MOC). The numerical results obtained from the modified model showed a good agreement with the four test cases, where the relative errors are improved by 0.26, 2.03, 9.56, and 36.67%, compared with the results from the original IAB model. The estimation for wave peak and valley is improved as well. Furthermore, the Bradley equation can be applied to establish the relationship between the dissipation coefficient and the Reynolds number. The modified model developed in this study takes into account the fluid CE effects and improves the prediction accuracy of wave amplitude of unsteady flow. HIGHLIGHTS
The numerical investigation of unsteady pipe flow with an efficient one-coefficient model.;
The fluid compression–expansion effect was considered in the energy dissipation term.;
The dissipation coefficient and the Reynolds number conform to the Bradley equation.;
The wave amplitude prediction of friction flow was improved by the modified IAB-CE model.; |
| first_indexed | 2024-12-13T09:38:55Z |
| format | Article |
| id | doaj.art-d06d67b366ae4b8f9d3be65876b5b495 |
| institution | Directory Open Access Journal |
| issn | 2709-8028 2709-8036 |
| language | English |
| last_indexed | 2024-12-13T09:38:55Z |
| publishDate | 2022-02-01 |
| publisher | IWA Publishing |
| record_format | Article |
| series | Aqua |
| spelling | doaj.art-d06d67b366ae4b8f9d3be65876b5b4952022-12-21T23:52:15ZengIWA PublishingAqua2709-80282709-80362022-02-0171233034410.2166/aqua.2022.144144Unsteady friction model modified with compression–expansion effects in transient pipe flowZ. Cao0Z. Wang1J. Deng2X. Guo3L. Lu4 School of Chemical Engineering and Technology, Xi'an Jiaotong University, No.28, West Xianning Road, Xi'an 710049, China School of Chemical Engineering and Technology, Xi'an Jiaotong University, No.28, West Xianning Road, Xi'an 710049, China School of Chemical Engineering and Technology, Xi'an Jiaotong University, No.28, West Xianning Road, Xi'an 710049, China School of Chemical Engineering and Technology, Xi'an Jiaotong University, No.28, West Xianning Road, Xi'an 710049, China Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR 999077, China This paper aims to modify the conventional one-coefficient instantaneous acceleration-based (IAB) model for better prediction of unsteady friction behavior. In this work, the energy dissipation caused by viscous stress during fluid volume compression–expansion (CE) was derived from the compressible Navier–Stokes equation. It is found that the energy dissipation term can be expressed by the product of the second-order partial derivative of velocity in space and the second viscosity coefficient. On this basis, a modified IAB-CE model was developed with the energy dissipation term and solved by the method of characteristic (MOC). The numerical results obtained from the modified model showed a good agreement with the four test cases, where the relative errors are improved by 0.26, 2.03, 9.56, and 36.67%, compared with the results from the original IAB model. The estimation for wave peak and valley is improved as well. Furthermore, the Bradley equation can be applied to establish the relationship between the dissipation coefficient and the Reynolds number. The modified model developed in this study takes into account the fluid CE effects and improves the prediction accuracy of wave amplitude of unsteady flow. HIGHLIGHTS The numerical investigation of unsteady pipe flow with an efficient one-coefficient model.; The fluid compression–expansion effect was considered in the energy dissipation term.; The dissipation coefficient and the Reynolds number conform to the Bradley equation.; The wave amplitude prediction of friction flow was improved by the modified IAB-CE model.;http://aqua.iwaponline.com/content/71/2/330compression–expansion effectsenergy dissipationpressure wavetransient pipe flowunsteady friction modelwater hammer |
| spellingShingle | Z. Cao Z. Wang J. Deng X. Guo L. Lu Unsteady friction model modified with compression–expansion effects in transient pipe flow Aqua compression–expansion effects energy dissipation pressure wave transient pipe flow unsteady friction model water hammer |
| title | Unsteady friction model modified with compression–expansion effects in transient pipe flow |
| title_full | Unsteady friction model modified with compression–expansion effects in transient pipe flow |
| title_fullStr | Unsteady friction model modified with compression–expansion effects in transient pipe flow |
| title_full_unstemmed | Unsteady friction model modified with compression–expansion effects in transient pipe flow |
| title_short | Unsteady friction model modified with compression–expansion effects in transient pipe flow |
| title_sort | unsteady friction model modified with compression expansion effects in transient pipe flow |
| topic | compression–expansion effects energy dissipation pressure wave transient pipe flow unsteady friction model water hammer |
| url | http://aqua.iwaponline.com/content/71/2/330 |
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