Beamforming based extension of semi-empirical noise modelling for low-speed axial flow fans

Benedek, Tamás; Vad, János

doi:10.1016/j.apacoust.2021.108018

Cited by 9 publications

(5 citation statements)

References 47 publications

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“…In order to estimate the order of magnitude of the effect of Re-dependence of CL and CD, the following illustrative example is given. Taking a realistic and representative low-speed axial flow fan [46] as a reference, Rec varies along the blade span within the range of 30000 -200000, due to the variation in the chord and in the flow velocity (the latter is also influenced by the rotor speed, 700 to 1400 1/min). Based on Figure 6, this variability in the Reynolds number may cause a variation in CL and CD up to 20 % and 30 %, respectively, depending on the α angle of attack.…”

Section: ) Semi-empirical Model For Predicting the Pvs Frequencymentioning

confidence: 99%

“…For illustrative comparison, detailed lift and drag coefficient data have been reproduced by the present authors from the literature, for an airfoil profile -left column, NACA23012 profile 44 -and for a cambered plate -right column, 417a profile. 45 The sketches of the two profiles are shown in Figure 4. Figure 5 shows the comparative lift and drag plots for the two profiles for Reynolds numbers in the order of magnitude of 10 4 .…”

Section: Reynolds Number Effectmentioning

confidence: 99%

“…b) Notable Reynolds-number-dependence in the lift coefficient. 45 Since the lift coefficient is related to the isentropic total pressure rise performed by the rotor cascade, 24,25 such dependence is to be considered in preliminary fan design. c) For moderate Reynolds numbers, the drag coefficient is substantially less for the cambered plate than for the airfoil.…”

Section: Reynolds Number Effectmentioning

confidence: 99%

“…Lift and drag coefficients at moderate Reynolds numbers. Left column: NACA23012 profile.44 Right column: 417a cambered plate 45.…”

mentioning

confidence: 99%

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Profile vortex shedding from low-speed axial fan rotor blades: a modelling overview

Daku

Vad

2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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This paper presents an overview of the characteristics potentially influencing the profile vortex shedding (PVS) phenomenon being relevant in noise and vibration of low-speed axial fan rotor blades. Dimensional analysis has been applied to explore the essential dimensionless quantities in a systematic and comprehensive manner. On this basis, limitations have been established, and simplifying assumptions have been set up in terms of PVS investigation. Groups of dimensionless characteristics playing a role in the semi-empirical model for predicting the PVS frequency were identified. The available semi-empirical model and its unique features related to the measurement evaluation methodology and Reynolds number dependence have been outlined. The presented comprehensive analysis provides guidelines from the perspective of transferability of the literature data on PVS from steady, isolated blade profile models to low-speed axial fan rotors. It also results in the formulation of objectives of future research related to PVS.

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Section: ) Semi-empirical Model For Predicting the Pvs Frequencymentioning

confidence: 99%

Section: Reynolds Number Effectmentioning

confidence: 99%

Section: Reynolds Number Effectmentioning

confidence: 99%

“…Lift and drag coefficients at moderate Reynolds numbers. Left column: NACA23012 profile.44 Right column: 417a cambered plate 45.…”

mentioning

confidence: 99%

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Profile vortex shedding from low-speed axial fan rotor blades: a modelling overview

Daku

Vad

2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Therefore, centrifugal fans need to be developed further to achieve high efficiency, save energy and reduce noise emissions. The latest design methods are based on computationa fluid dynamics (CFD) simulations and aeroacoustic analysis [1][2][3][4][5][6]. At the same time, experimental measurements are developed using state-of-the-art techniques, such as particle image velocimetry (PIV) [7,8].…”

Section: Introductionmentioning

confidence: 99%

Archives of Thermodynamics

Pritz,

Probst,

Wiśniewski

et al. 2021

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Besides centrifugal pumps, centrifugal fans are the most common turbomachines used in technical applications. They are commonly used in power engineering systems, such as heat engines and chillers, heating, ventilation, and air conditioning systems, supply and exhaust air systems. They are also used as machines consuming final energy (electricity). Therefore, any improvement in their efficiency affects the efficiency of energy generation and the level of electricity consumption. Many efforts have been made so far to find the most efficient numerical method of modelling flows in fans. However, only a few publications focus on the unsteadiness that may have an impact on device efficiency and noise generation. This paper presents an attempt to identify unsteadiness in the flow through a centrifugal fan by means of computational fluid dynamics and computational aeroacoustics methods. The works were performed using the Ansys CFX commercial software and the results of numerical studies are compared with experimental data.

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Combined acoustic and aerodynamic investigation of the effect of inlet geometry on tip leakage flow noise of free-inlet free-exhaust low-speed axial flow fans

2022

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Beamforming based extension of semi-empirical noise modelling for low-speed axial flow fans

Cited by 9 publications

References 47 publications

Profile vortex shedding from low-speed axial fan rotor blades: a modelling overview

Profile vortex shedding from low-speed axial fan rotor blades: a modelling overview

Archives of Thermodynamics

Combined acoustic and aerodynamic investigation of the effect of inlet geometry on tip leakage flow noise of free-inlet free-exhaust low-speed axial flow fans

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