Simulation of Broadband Noise Sources of an Axial Fan under Rotating Stall Conditions

Zhang, Lei; Wang, Rui; Wang, Songling

doi:10.1155/2014/507079

Cited by 13 publications

(4 citation statements)

References 34 publications

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“…However, changes in these parameters are finally reflected with changes in integral parameters. Therefore, the verification method using integral parameters is widely applied in many researches [21,[24][25][26][27]. To verify the mesh independence, fans with mesh numbers of 3.82, 4.26, 4.65, 5.33 and 5.56 million are simulated in this study, as shown in Table 3.…”

Section: Meshingmentioning

confidence: 99%

Prediction of Performance of a Variable-Pitch Axial Fan with Forward-Skewed Blades

Ye¹,

Fan²,

Zhang³

et al. 2019

Energies

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For a single-stage variable-pitch axial fan, the aerodynamic performance and through flow with and without blade skewing are examined numerically. Simulated results show that the total pressure rise and efficiency increase by 2.99% and 0.16%, respectively, with the best forward-skewed angle of θ = 3° at the design conditions. At the blade pitch angles of β = 29° and 35°, the total pressure rises and efficiency of the fan with θ = 3.0° under the highest efficiency point change by −0.55%, −0.53% and 1.39%, 2.11%, respectively. At design and off-design conditions, the forward-skewed blades mitigate tip leakage and delay the emergence of separation flow at the blade root, these benefits are higher at the higher blade pitch angle. The θ = 3.0° forward skew effectively raises the stage performance of the impeller and guide vanes.

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Section: Meshingmentioning

confidence: 99%

Prediction of Performance of a Variable-Pitch Axial Fan with Forward-Skewed Blades

Ye¹,

Fan²,

Zhang³

et al. 2019

Energies

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“…where k 0 is a constant, k 1 is throttle coefficient, ρ is density of the air, and U is velocity component of the z axial. Details of boundary conditions and throttle models are presented in [14].…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…The internal flow field of the fan is related to the aerodynamic noise. The noises of the fan mainly consist of aerodynamic noise, machinery noise and radiation noise [14]. Among them, aerodynamic noise occupies the main position, which includes the rotational noise and vortex noise.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Acoustic Characteristics of an Axial Fan under Rotating Stall Condition

Zhang

Yan

et al. 2017

Energies

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Axial fan is an important piece of equipment in the thermal power plant that provides enough air for combustion of coal. This paper focuses on the aerodynamic noise characteristics of an axial fan in the development from stall inception to stall cells. The aerodynamic noise characteristic of monitoring region in time and frequency domains was simulated employing the large-eddy simulation (LES), with the addition of throttle setting and the Ffowcs Williams-Hawkings (FW-H) noise model. The numerical results show that, under the design condition, the acoustic pressure presents regular periodicity along with the time. The noise energy is concentrated with high energy of the fundamental frequency and high order harmonics. During the stall inception stage, the acoustic pressure amplitude starts fluctuating and discrete frequencies are increased significantly in the low frequency; among them, there are three obvious discrete frequencies: 27.66 Hz, 46.10 Hz and 64.55 Hz. On the rotating stall condition, the fluctuation of the acoustic pressure level and amplitude are more serious than that mentioned above. During the whole evolution process, the acoustic pressure peak is difficult to keep stable all the time, and a sudden increase of the peak value at the 34.5th revolution corresponds to the relative velocity's first sudden increase at the time when the valve coefficient is 0.780.

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“…us, except for the unsteady flow of the pump when pump operates at partial load condition, the periodic instability caused by the internal rotor-stator interaction further deteriorates the flow field and operation condition. Even though the unsteady flow feature that results from partial load condition has been investigated deeply in the turbomachinery, compressor, and fan [23][24][25], there are few reports about the rotor-stator interaction or the shaft system vibration caused by the rotor-stator interaction of the mixed-flow pump under the circumstance of partial load condition, and the relationship between the shaft vibration and rotor-stator interaction flow is also not revealed. Many scholars just focus on the hydrodynamic instabilities caused by unsteady characteristic of rotor-stator interaction flow or the energy loss of the pump running at partial load condition.…”

Section: Introductionmentioning

confidence: 99%

Vibration of Shaft System in the Mixed‐Flow Pump Induced by the Rotor‐Stator Interaction under Partial Load Conditions

Wei

Shi

et al. 2018

Shock and Vibration

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In order to reveal the relationship between rotor-stator interaction-induced unsteady flow and the shaft vibration of the mixed-flow pump, PIV (particle image velocimetry) and axis orbit experiments were carried out synchronously in a mixed-flow pump under designed flow rate (1.0Qdes) and the partial load conditions (0.4Qdes and 0.2Qdes). The distribution of the relative velocity and the vorticity in the rotor-stator interaction region at a certain position of the mixed-flow pump impeller was captured; the axis orbit diagram and the time-domain diagram of shaft system were acquired as well. Besides, the waterfall diagrams of the frequency spectrum under different flow rate conditions were compared. The results show that the backflow and the flow separation phenomenon appear in the rotor-stator interaction flow field under the partial load condition, indicating the flow instability. The medium-frequency exciting force and high-frequency exciting force induced by these unstable flows resulting from the rotor-stator interaction are the main factors to intensify the shaft vibration at the power frequency. The rotor-stator interaction under partial load condition is the main reason for the deterioration of shaft system vibration. The 2X frequency also affects the axis orbit in a low level, while other frequencies have less influence on the shaft vibration. The research results can provide the reference and theory instruction for revealing the operating characteristic of mixed-flow pump when it operates under partial load conditions and to reduce or to prevent the deterioration of vibration of shaft system.

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Simulation of Broadband Noise Sources of an Axial Fan under Rotating Stall Conditions

Cited by 13 publications

References 34 publications

Prediction of Performance of a Variable-Pitch Axial Fan with Forward-Skewed Blades

Prediction of Performance of a Variable-Pitch Axial Fan with Forward-Skewed Blades

Numerical Study on the Acoustic Characteristics of an Axial Fan under Rotating Stall Condition

Vibration of Shaft System in the Mixed‐Flow Pump Induced by the Rotor‐Stator Interaction under Partial Load Conditions

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