Experimental Research into Relation between Propeller Fan's Flow Field and Noise : Relationships between Difference of Tip Flow Behavior in Each Operation Point and Its Noise(Fluids Engineering)

誠治, 中島; 彰二, 山田; 幸司, 吉瀬

doi:10.1299/kikaib.76.767_1042

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…On the other hand, in a study on the turbulent noise of a low pressure axial fan, Fukano et al suggested that the broadband noise was mainly generated because of the vortex shedding to the wake if the turbulence of the incoming flow to the fan is weak [6]. Whereas the relationship between the tip vortex and noise has been discussed in a study of the aerodynamic noise from the propeller fan [7], there are several reports stating that the affect of the tip vortex on the fan noise is small in the vicinity of the design point [8]. Thus, several factors related to the flow regime affect the fan noise at the main operation points.…”

Section: Introductionmentioning

confidence: 99%

An Experimental and Numerical Study on Wake Vortex Noise of a Low Speed Propeller Fan

Sasaki¹,

Torise²,

Hayashi³

2012

OJFD

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In order to clarify the relationship between the aerodynamic noise and the flow regime around the rotating blade of a propeller fan operated at the maximum efficiency point and the off-design point, the characteristics of fans with different solidity impellers were analyzed experimentally. At the off-design point, the broadband noise of the high solidity fan was much larger than that of the low solidity fan because the relative velocity increased according to the solidity and the noise sources increased because of the number of blades. In the case of the low solidity fan, the broadband noise due to wake vortex shedding was generated at the off-design point in the low flow rate domain and the maximum efficiency point because the relative flow around the blade separated easily.

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Section: Introductionmentioning

confidence: 99%

An Experimental and Numerical Study on Wake Vortex Noise of a Low Speed Propeller Fan

Sasaki¹,

Torise²,

Hayashi³

2012

OJFD

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Effect of straightening plates on jet from ducted propeller fan

Kikuchi

Kozato

Lee

et al. 2018

Transactions of the JSME (In Japanese)

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A propeller fan jet with a duct and straightening plates for the purpose of making a high velocity jet at the far away of propeller was experimentally investigated. As a result, following conclusions were obtained. When the duct and the straightening plates are attached to the propeller, the center velocity at the position away from the propeller becomes fast, because the swirl of the jet becomes weak. As the number of plates increases, the center velocity increases. But when the number of plates exceeds a certain value, the center velocity becomes slow. This is similar about the length of the plates. When the plate is tilted, the larger the tilt angle of the plate is, the slower the center speed becomes in the downstream.

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Three-dimensional structure of tip vortex in a half-ducted propeller fan

Kusano

Furukawa²,

Yamada³

2014

Transactions of the JSME (In Japanese)

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The tip vortex has an important role on the aerodynamic performance and noise of half-ducted propeller fans. The present paper provides better understanding on the three-dimensional structure of the tip vortex in a half-ducted propeller fan, aiming at the effective control of it. A numerical analysis was carried out using a detached eddy simulation (DES). DES results were validated by the comparison with LDV measurement data. Vortex centers around the propeller fan were identified by the critical point theory. The numerical results show that the tip vortex in the opened region upstream of the shroud leading edge is advected nearly along main stream, whereas the tip vortex in the ducted region covered by the shroud is turned toward the tangential direction by the interaction of the tip vortex with the shroud wall. The behavior of the tip vortex in its inception region does not depend on the flow rate, because the relative inflow angle at the leading edge near the blade tip is independent of the flow rate. On the other hand, the behavior of the tip vortex in the ducted region is sensitive to the flow rate. As the flow rate is decreased, the tip vortex interacts more strongly with the shroud wall, and as a result, its trajectory is inclined more largely in the tangential direction in the ducted region. In the opened region, the core radius and circulation of the tip vortex increase rapidly at constant growth rate in the streamwise direction. In the ducted region, on the other hand, the tip vortex decays gradually in the downstream direction. The maximum circulation of the tip vortex amounts to 60～75% of the circulation of the bound vortices released from the near tip region of the blade. It is found that the jet-like axial velocity distribution is formed around the tip vortex center by the favorable pressure gradient along the tip vortex center resulting from its rapid growth in the opened region.

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Experimental Research into Relation between Propeller Fan's Flow Field and Noise : Relationships between Difference of Tip Flow Behavior in Each Operation Point and Its Noise(Fluids Engineering)

Cited by 3 publications

References 8 publications

An Experimental and Numerical Study on Wake Vortex Noise of a Low Speed Propeller Fan

An Experimental and Numerical Study on Wake Vortex Noise of a Low Speed Propeller Fan

Effect of straightening plates on jet from ducted propeller fan

Three-dimensional structure of tip vortex in a half-ducted propeller fan

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