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Numerical Simulation of Flow-Induced Noise in High Pressure Reducing Valve.

Wei L, Zhu G, Qian J, Fei Y, Jin Z - PLoS ONE (2015)

Bottom Line: Noise directivity analysis and spectrum characteristics indicate that the perforated plate could help to reduce noise effectively.Inlet pressure has great effects on sound pressure level (SPL).When the maximum Ma is close to 1, SPL at low frequency becomes very high.

View Article: PubMed Central - PubMed

Affiliation: Institute of Process Equipment, Zhejiang University, Hangzhou, China.

ABSTRACT
The main objective of this paper is to study the characteristics of flow-induced noise in high pressure reducing valve (HPRV) and to provide some guidance for noise control. Based on computational fluid dynamics (CFD), numerical method was used to compute flow field. Ffowcs Williams and Hawkings Model was applied to obtain acoustic signals. The unsteady flow field shows that noise sources are located at the bottom of plug for valve without perforated plate, and noise sources are behind the plate for valve with perforated plate. Noise directivity analysis and spectrum characteristics indicate that the perforated plate could help to reduce noise effectively. Inlet pressure has great effects on sound pressure level (SPL). The higher inlet pressure will lead to larger SPL at high frequency. When the maximum Ma is close to 1, SPL at low frequency becomes very high.

No MeSH data available.


Turbulent intensity variation along streamlines.For l = 0.9~1.2 m (from perforated plate to outlet) turbulent intensity is much larger than other region.
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pone.0129050.g006: Turbulent intensity variation along streamlines.For l = 0.9~1.2 m (from perforated plate to outlet) turbulent intensity is much larger than other region.

Mentions: Admittedly, the flow status has much influence on acoustic field. In Fig 5 high velocity occurs mainly around the valve plug and at the outlet cavity. It can be seen that the high velocity area of Valve A is wider than Valve B. Velocity at rest part is much lower. Fig 6 shows turbulent intensity variation along streamline for the two models. When streamline length l > 0.8 m, turbulent intensity increases fast. For l = 0.9~1.2 m (from perforated plate to outlet) turbulent intensity is much larger than other region where the turbulent intensity is kept under 1250%. This is because that steam expands in the outlet cavity and causes great disturbances. The difference of Mach number (Ma) between the two models is clearly in Fig 7. Ma at l = 0.9~1.2 m is higher than other region and Ma > 1 indicates the supersonic flow. Ma of Valve B is 30~60% lower than Valve A.


Numerical Simulation of Flow-Induced Noise in High Pressure Reducing Valve.

Wei L, Zhu G, Qian J, Fei Y, Jin Z - PLoS ONE (2015)

Turbulent intensity variation along streamlines.For l = 0.9~1.2 m (from perforated plate to outlet) turbulent intensity is much larger than other region.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465344&req=5

pone.0129050.g006: Turbulent intensity variation along streamlines.For l = 0.9~1.2 m (from perforated plate to outlet) turbulent intensity is much larger than other region.
Mentions: Admittedly, the flow status has much influence on acoustic field. In Fig 5 high velocity occurs mainly around the valve plug and at the outlet cavity. It can be seen that the high velocity area of Valve A is wider than Valve B. Velocity at rest part is much lower. Fig 6 shows turbulent intensity variation along streamline for the two models. When streamline length l > 0.8 m, turbulent intensity increases fast. For l = 0.9~1.2 m (from perforated plate to outlet) turbulent intensity is much larger than other region where the turbulent intensity is kept under 1250%. This is because that steam expands in the outlet cavity and causes great disturbances. The difference of Mach number (Ma) between the two models is clearly in Fig 7. Ma at l = 0.9~1.2 m is higher than other region and Ma > 1 indicates the supersonic flow. Ma of Valve B is 30~60% lower than Valve A.

Bottom Line: Noise directivity analysis and spectrum characteristics indicate that the perforated plate could help to reduce noise effectively.Inlet pressure has great effects on sound pressure level (SPL).When the maximum Ma is close to 1, SPL at low frequency becomes very high.

View Article: PubMed Central - PubMed

Affiliation: Institute of Process Equipment, Zhejiang University, Hangzhou, China.

ABSTRACT
The main objective of this paper is to study the characteristics of flow-induced noise in high pressure reducing valve (HPRV) and to provide some guidance for noise control. Based on computational fluid dynamics (CFD), numerical method was used to compute flow field. Ffowcs Williams and Hawkings Model was applied to obtain acoustic signals. The unsteady flow field shows that noise sources are located at the bottom of plug for valve without perforated plate, and noise sources are behind the plate for valve with perforated plate. Noise directivity analysis and spectrum characteristics indicate that the perforated plate could help to reduce noise effectively. Inlet pressure has great effects on sound pressure level (SPL). The higher inlet pressure will lead to larger SPL at high frequency. When the maximum Ma is close to 1, SPL at low frequency becomes very high.

No MeSH data available.