The Influence of Geometric Parameters on F. C. Centrifugal Fan Noise

1987 ◽  
Vol 109 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Ken Morinushi
Keyword(s):  
Low Noise ◽  
Diameter Ratio ◽  
Geometric Parameters ◽  
Centrifugal Fan ◽  
Fan Noise ◽  
Noise Characteristics ◽  
Centrifugal Fans ◽  
Inner Diameter ◽  
Optimal Values ◽  
Axial Clearance

In this report, through experiments the influence of five major geometric parameters on noise and aerodynamic performance of forward curved (F.C.) centrifugal fans was studied. The parameters considered are: (1) width-inner diameter ratio of impeller, (2) axial clearance between the fan inlet nozzle and the impeller shroud plate, (3) blade-setting angle, (4) blade pitch-chord ratio, and (5) spiral extension index of the scroll. Noise characteristics were evaluated by means of the specific noise level (A-weighted) at every operating point except the surging region. The optimal values for the parameters to realize low noise are discussed. Design diagrams for low noise F.C. centrifugal fans are shown.

Optimization of Low-Noise and Large Air Volume Blower Based on Load Characteristic

2015 ◽  
Vol 656-657 ◽  
pp. 700-705
Author(s):  
Jian Dong Chen ◽  
Bei Bei Sun
Keyword(s):  
Flow Rate ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Strong Wind ◽  
Centrifugal Fan ◽  
Fan Noise ◽  
Load Characteristic ◽  
Air Volume ◽  
Actual Working ◽  
Working Point

The blower is a kind of garden machinery, which blows strong wind to clean up leaves by a centrifugal fan, but it causes a loud aerodynamic noise. To compromise the contradiction between large air flow rate and low fan noise, some optimizations are proposed to reduce fan noise without lowering its air volume. In this paper, a CFD numerical model to compute airflow field of blower is established, where the centrifugal fan is simulated by the MRF model, and theturbulent model is selected. By smoothing the transition section, improving the volute tongue and optimizing the shape and optimizing number of fan blade, the blower work performance is increased obviously. In order to find out the actual working point, both the fan and motor load characteristic curves are drawn out. The simulation results show that, at the actual working point, the speed of the centrifugal fan is reduced, while the flow rate of blower is raised up. The optimizations are applied to the blower, and the experiment of the improved blower shows the flow rate is increased 5%, and the noise is reduced 2dB.

Study of High Efficiency and Low Noise Centrifugal Fan

2011 ◽  
Author(s):  
Takanori Nagae ◽  
Zhiming Zheng
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Low Noise ◽  
Leakage Flow ◽  
Pressure Side ◽  
Centrifugal Fan ◽  
Air Conditioner ◽  
Air Conditioners ◽  
Leakage Flows ◽  
Centrifugal Fans

Centrifugal fans are widely used for air-conditioning equipments. Demands for air conditioners have arisen for quiet considered the indoor condition, energy saving associated with the global warming, and which have made it important to develop high performance fans. In order to meet these demands, the technology was studied to reduce leakage flow for a high efficiency and low noise centrifugal fan in this research. Leakage flow occurs when a part of air discharged from fans flows into a gap between the bellmouth and the shroud. This flow is the pressure loss because it returns from the high-pressure side to the low-pressure side wastefully. Furthermore, the high noise is caused, because this leakage air can’t flow along the shroud. As the final successful technology to reduce leakage flow, we have developed for the new bellmouth with multiple ribs on the bellmouth plane placed opposite fan. By using the new bellmouth, the centrifugal fan’s motor input for the 4-direction ceiling-embedded cassette type air conditioner has been reduced by 5.4[%] and the noise by 1.2[dBA]. We analyzed the leakage flow structures of the centrifugal fan were analyzed by the numerical simulation and LDV measurements. It has been found that the leakage flow is decreased, since the partial leakage flows back in an opposite direction to a gap between the bellmouth and the shroud. Additionally, it has been found that the turbulence intensity of outlet airflow is decreased by the new bellmouth.

Prediction of the Aerodynamic Noise Generated by a Centrifugal Fan: Numerical Results and Experimental Validation

2006 ◽  
Author(s):  
Rafael Ballesteros-Tajadura ◽  
Sandra Velarde-Sua´rez ◽  
Juan Pablo Hurtado-Cruz ◽  
Bruno Pereiras-Garci´a
Keyword(s):  
Three Dimensional ◽  
Prediction Method ◽  
Numerical Results ◽  
Experimental Results ◽  
Aerodynamic Noise ◽  
Centrifugal Fan ◽  
Fan Noise ◽  
Unsteady Forces ◽  
Model Extension ◽  
Centrifugal Fans

Centrifugal fans are widely used in several applications and, in some cases, the noise generated by these machines has become a serious problem. Usually, the centrifugal fan noise is dominated by tones at the blade passage frequency and its higher harmonics. This is a consequence of the strong interaction between the flow discharged from the impeller and the volute tongue. The purpose of this study is to develop a prediction method for the noise generated by a centrifugal fan. A three-dimensional numerical simulation of the complete unsteady flow on the whole impeller-volute configuration has been carried out using the computational fluid dynamics code FLUENT®. The unsteady forces applied by the fan blades to the fluid are obtained from the data provided by the simulation. The Ffowcs Williams and Hawkings model extension of Lighthill’s analogy predicts the aerodynamic noise generated by the centrifugal fan from these unsteady forces. Also, the noise generated by the fan has been measured experimentally, and the experimental results have been compared to the numerical results in order to validate the aerodynamic noise prediction methodology. A good agreement has been found between the numerical and the experimental results.

Noise reduction mechanisms for the inclined leading edge vaned diffuser in a centrifugal fan

2017 ◽  
Vol 231 (1) ◽  
pp. 68-83 ◽  
Author(s):  
Gong Wu Qi ◽  
Zhang Wei
Keyword(s):  
Noise Reduction ◽  
Pressure Fluctuation ◽  
Numerical Study ◽  
Second Harmonic ◽  
Leading Edge ◽  
Centrifugal Fan ◽  
Fan Noise ◽  
Vaned Diffuser ◽  
Reduction Mechanisms ◽  
Centrifugal Fans

An experimental and numerical study to explore the noise reduction mechanism for the inclined leading edge vaned diffuser in centrifugal fans is described. Inclined leading edge vaned diffuser is useful in improving fan performance, increasing operating range, and reducing fan noise. The generation of fan noise is related to the pressure fluctuation on the diffuser vane surface, particularly the leading edge. Numerical results show that pressure fluctuation on the inclined leading edge vaned diffuser surface remarkably decreases, unlike that of the original diffuser. The pressure fluctuation is dominated by the components at the blade passing frequency and its second harmonic.

scholarly journals Volute characteristics of centrifugal fan based on dynamic moment correction method

2018 ◽  
Vol 233 (2) ◽  
pp. 176-185 ◽  
Author(s):  
Shuiqing Zhou ◽  
Yuebing Li
Keyword(s):  
Numerical Calculation ◽  
Line Shape ◽  
Correction Method ◽  
Correction Coefficient ◽  
Centrifugal Fan ◽  
Optimization Scheme ◽  
Fan Noise ◽  
Calculation Technique ◽  
Noise Characteristics ◽  
Dynamic Moment

The multi-blade centrifugal fan features an abundance of vanes (>48) and a spiral volute. The flowability and noise characteristics of the centrifugal fan are dependent on the type-line of volute and tongue geometries at the volute exit. The aim of this research was to find a better volute type-line for fan noise reduction without compromising on the performance. First, the viscosity factors of gas were used to modify the type-line shape of the volute by introducing a dynamic moment correction coefficient; a modified volute was then obtained to match the new fan system. Next, the performance of the original fan and retrofit fan were tested. The optimization scheme was verified and the feasibility of the proposed numerical calculation technique was confirmed.

scholarly journals Flow and Noise Characteristics of Centrifugal Fan in Low Pressure Environment

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 985 ◽  
Author(s):  
Xilong Zhang ◽  
Yongliang Zhang ◽  
Chenggang Lu
Keyword(s):  
Ambient Pressure ◽  
Characteristic Curve ◽  
Normal Pressure ◽  
Low Pressure ◽  
Centrifugal Fan ◽  
Working Process ◽  
Fan Noise ◽  
Environmental Pressure ◽  
Noise Characteristics ◽  
Consumption Curve

The influence of low-pressure environment on centrifugal fan’s flow and noise characteristics was studied experimentally and numerically. A testbed was established to conduct the experimental test on the performance of a centrifugal fan, and the characteristic curve and power consumption curve of the fan under different pressure were obtained. Then the simulation model of the centrifugal fan was established, which was used to simulate the working process of centrifugal fan under different negative pressures. The results showed that the total pressure and static pressure of the fan decrease with the decrease of the ambient pressure. The total and static pressures of the fan under 60 kPa pressure condition decreased by 42.3% and 38.3%, respectively, compared with those of fan under the normal pressure. The main reason for this phenomenon is that the decrease of the environmental pressure leads to the decrease of air density. Besides, with the drop of environmental pressure, the sound pressure and sound power of the fan noise decreases.

scholarly journals Effects of the Geometric Parameters of Mixer on the Mixing Process of Foam Concrete Mixture and Its Energy Efficiency

2020 ◽  
Vol 10 (22) ◽  
pp. 8055
Author(s):  
Sergey A. Stel’makh ◽  
Evgenii M. Shcherban’ ◽  
Anatolii I. Shuiskii ◽  
Al’bert Yu. Prokopov ◽  
Sergey M. Madatyan ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Lower Energy ◽  
Geometric Parameters ◽  
Concrete Mixture ◽  
Mixing Process ◽  
Conical Part ◽  
Foam Concrete ◽  
Optimal Range ◽  
Optimal Values

The paper studies the influence of the geometric parameters of the mixer on the mixing process, the construction of the mixing body, its location in the mixer bulk, and the mixer shape and geometry. The technique of calculating the power spent on mixing the foam concrete mixture is described. The effects of the ratio of the mixture height to the mixer diameter, the number and width of reflective partitions, and the shape of the conical part of the mixer on the homogeneity of the foam concrete mixture and the power consumption are considered. The optimal ratios of the foam concrete mixture height to the mixer diameter have been determined. Moreover, the optimal range of the ratios of the partition width to the mixer diameter has been established, in order to obtain a homogeneous foam concrete mixture throughout the volume with lower energy consumption. The optimal values of the angle of the mixer conical part for the preparation of a foam concrete mixture have been determined.

scholarly journals A Four-Channel Low-Noise Readout IC for Air Flow Measurement Using Hot Wire Anemometer in 0.18 μm CMOS Technology

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4694
Author(s):  
Kyeongsik Nam ◽  
Hyungseup Kim ◽  
Yongsu Kwon ◽  
Gyuri Choi ◽  
Taeyup Kim ◽  
...  
Keyword(s):  
Supply Voltage ◽  
Air Flow ◽  
Low Noise ◽  
Cmos Process ◽  
Significant Information ◽  
Flow Measurements ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Op Amp ◽  
Noise Characteristics

Air flow measurements provide significant information required for understanding the characteristics of insect movement. This study proposes a four-channel low-noise readout integrated circuit (IC) in order to measure air flow (air velocity), which can be beneficial to insect biomimetic robot systems that have been studied recently. Instrumentation amplifiers (IAs) with low-noise characteristics in readout ICs are essential because the air flow of an insect’s movement, which is electrically converted using a microelectromechanical systems (MEMS) sensor, generally produces a small signal. The fundamental architecture employed in the readout IC is a three op amp IA, and it accomplishes low-noise characteristics by chopping. Moreover, the readout IC has a four-channel input structure and implements an automatic offset calibration loop (AOCL) for input offset correction. The AOCL based on the binary search logic adjusts the output offset by controlling the input voltage bias generated by the R-2R digital-to-analog converter (DAC). The electrically converted air flow signal is amplified using a three op amp IA, which is passed through a low-pass filter (LPF) for ripple rejection that is generated by chopping, and converted to a digital code by a 12-bit successive approximation register (SAR) analog-to-digital converter (ADC). Furthermore, the readout IC contains a low-dropout (LDO) regulator that enables the supply voltage to drive digital circuits, and a serial peripheral interface (SPI) for digital communication. The readout IC is designed with a 0.18 μm CMOS process and the current consumption is 1.886 mA at 3.3 V supply voltage. The IC has an active area of 6.78 mm2 and input-referred noise (IRN) characteristics of 95.4 nV/√Hz at 1 Hz.

Design on Parameterized Drafting System of Centrifugal Fan

2010 ◽  
Vol 34-35 ◽  
pp. 192-196
Author(s):  
Jiang Zhu ◽  
Limin Chen ◽  
Ping Yuan Xi
Keyword(s):  
Aerodynamic Force ◽  
Geometric Parameters ◽  
Rapid Response ◽  
Design Parameters ◽  
Centrifugal Fan ◽  
Aerodynamic Design ◽  
Key Factors ◽  
Fan Speed ◽  
Force Calculation

The impeller is the important pneumatic part of centrifugal fan, and its structure performances are key factors which affect the whole performances of fan. The CAD module of centrifugal fan can realize the automation of aerodynamic force calculation. According to demands, computer can automatically complete aerodynamic force calculation and further determine major geometric parameters of impeller of fan. Speed coefficient and diametral quotient are two important parameters reflecting the character of ventilating fan. The relation curve between the speed coefficient and diametral quotient of various fans is plotted in this paper. The CAD module of impeller of centrifugal fan can realize such functions as aerodynamic design and parameterization drawing of impeller, and can accomplish rapid response from receiving design parameters to profiled impeller of fan, so that it can improve the quality of drawing.

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