Influence of the karman vortex street on the broadband noise generated from a multiblade fan

Sasaki, Soichi; Kodama, Y.; Hayashi, H.; Hatakeyama, Makoto

doi:10.1007/s11630-005-0002-6

Cited by 12 publications

(10 citation statements)

References 5 publications

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“…The previous studies about car air-conditioners indicate that the fan blades and the scrolls are one of the most important parts for blowing performance and noise level. 3,5,11 In this section, multi-objective optimization is conducted for a blower unit to maximize the pressure efficiency and minimize the SPL using a Kriging-surrogate-based genetic algorithm (GA). Data mining and flow visualization are also conducted into the design candidates of blower units obtained by the optimization.…”

Section: Design Optimizationmentioning

confidence: 99%

Multi-objective design optimization of a high efficiency and low noise blower unit of a car air-conditioner

Kamada

Shimoyama

Sato

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part D:

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Car air-conditioners consist of a blower unit and a heater unit. A blower unit sends wind to a heater unit, and a heater unit adjusts the temperature inside the vehicle. Blower units of car air-conditioners are required to be smaller, lighter, noiseless, and power-saving. However, it is difficult and expensive to predict the noise directly by computational fluid dynamics simulation. Hereupon, this study employs an indirect noise prediction method based on a noise prediction theory to evaluate noise for blower units inexpensively. This method is investigated through a comparison with actual sound pressure level measurement. Then, using this method, this study moves to design optimization of a blower unit of car air-conditioners. The optimization aims to improve total pressure efficiency and sound pressure level from the current design that has been employed for a real commercial vehicle. This study employs a genetic algorithm to explore global optima in a two-objective problem. The present genetic algorithm is assisted by the Kriging surrogate model to reduce computational cost required for evaluating objective functions. The optimization results indicate that the optimized blower unit involves a multi-blade fan with the high chord-pitch ratio to decrease the loss of total pressure efficiency, which is often induced by the flow separation on the blade and the swirling flow on the meridional plane. In addition, the sound pressure level of blower unit can be reduced by decreasing the local flow velocity on the meridian plane due to a blockage factor. A blower unit, which has a scroll with a large tongue angle, shows high total pressure efficiency because the increase in eddy loss is suppressed at the tongue. They suggest the importance of the matching of multi-blade fan and scroll to achieve the good overall performance of a blower unit.

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Section: Design Optimizationmentioning

confidence: 99%

Multi-objective design optimization of a high efficiency and low noise blower unit of a car air-conditioner

Kamada

Shimoyama

Sato

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…For the NACA airfoils, CD was determined based on Sheldahl and Klimas, 1981, while for the flat plates it was computed from the Blasius drag law (Schlichting and Gersten, 2016). As no case-specific CD data was available for the cambered plate (Sasaki et al, 2005), the use of CD was omitted in that case.…”

Section: Figure 5 the Limiting Reynolds Number As A Function Of Relative Thickness For Various Angles Of Attackmentioning

confidence: 99%

“…The noise generated by the vortex shedding of ventilating fans has been in the focus of recent research (Dou et al, 2016, Lee et al, 1993, Sasaki et al, 2005. Dou et al, 2016, states that noise generated by vortex shedding is the primary source of noise for small fans.…”

Section: Introduction and Objectivesmentioning

confidence: 99%

“…Literature data, selected as being intentionally independent from the studies by the present authors, are collected and presented in a systematic manner for a wide range of profile geometries and operating conditions. The literature cases incorporate symmetrical (Hersh et al, 1974, Yarusevych et al, 2009, Yarusevych and Boutilier, 2011, Bauer, 1961, Paterson et al, 1973, Brooks et al, 1989 and non-symmetrical (De Gennaro and Kuehnelt, 2012) NACA profiles, cambered plates (Sasaki et al, 2005), and flat plates (Bauer, 1961). Based on aerodynamic and aeroacoustic measurements, K is determined for α=0°, then the dependence on α is also taken into consideration.…”

Section: Introduction and Objectivesmentioning

confidence: 99%

See 1 more Smart Citation

A semi-empirical model for predicting the frequency of profile vortex shedding relevant to low-speed axial fan blade sections

Balla

Vad

2019

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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This paper extends existing semi-empirical models on the frequency prediction of vortex shedding. Moderate Reynolds numbers are investigated being of interest in low-speed axial fan design. By an extensive literature review, a new parametrization is proposed for the factor establishing a connection between boundary layer properties and vortex shedding characteristics. Measurement data on symmetrical and non-symmetrical NACA profiles, and on flat and cambered plates, are processed. It is found that the value of the factor is influenced by the relative thickness of the profiles and by the angle of attack. Based on the measurement results, an empirical value is given for the vortex spacing ratio for flow past airfoils. With the use of the proposed empirical model, the vortex shedding frequency of various airfoil profiles and operating conditions can be predicted.

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“…9 as one of the primary noise source of small scale ventilating fans, and thus been the subject of recent research. 9–11…”

Section: Introduction and Objectivesmentioning

confidence: 99%

An empirical model to determine lift and drag coefficients of cambered plates at moderate Reynolds numbers

Balla

Vad

2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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This article presents the lift and drag coefficients of cambered plate blade sections of different relative camber at moderate Reynolds numbers. Relative cambers between 0% and 8% are investigated at an angle of attack range from 0° to 10°. Based on own measurements and literature data, empirical formulae are proposed for the determination of the lift and drag coefficients for Reynolds numbers within the range of 60,000 to 300,000. The formulae determine the lift and drag coefficients as a function of angle of attack, relative camber, and Reynolds number. Third-order polynomials have been proven to be suitable for the empirical formulae. The coefficients of the third-order polynomials have been determined and reported by the authors herein.

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Influence of the karman vortex street on the broadband noise generated from a multiblade fan

Cited by 12 publications

References 5 publications

Multi-objective design optimization of a high efficiency and low noise blower unit of a car air-conditioner

Multi-objective design optimization of a high efficiency and low noise blower unit of a car air-conditioner

A semi-empirical model for predicting the frequency of profile vortex shedding relevant to low-speed axial fan blade sections

An empirical model to determine lift and drag coefficients of cambered plates at moderate Reynolds numbers

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