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.

Development of High Efficiency and Low Noise Cross-Flow Fans for Room Air Conditioner Indoor Unit

2014 ◽  
Author(s):  
Hironobu Yamakawa
Keyword(s):  
High Efficiency ◽  
Length Distribution ◽  
Cross Flow ◽  
Low Noise ◽  
Navier Stokes ◽  
Outer Diameter ◽  
Air Conditioner ◽  
Blade Edge ◽  
Sinusoidal Shape ◽  
Cross Flow Fan

Cross flow fans are used for fan systems in a household room air conditioner indoor unit. In recently, in the view of environmental problem and cost saving, energy saving performance is important specification for users. Reducing fan motor electric power consumption is effective for this purpose. And also low noise fans are needed for comfortable circumferences. To meet these user needs, we developed a high efficiency and silent cross flow fan using CFD (Computational Fluid Dynamics) and experiments. In CFD, numerical model is calculated by commercial software using steady state, Reynolds-averaged Navier-Stokes (RANS) and k-ε turbulent flow model. The developed cross flow fan is geometrically characterized by the solidity (the ratio of the blade pitch and blade cord length) distribution, and the blade edge shape. The solidity average of developed fan was larger than the conventional fan and the solidity distribution was smooth. And the developed fan has the sinusoidal shape of the outer diameter edge. This sinusoidal shape edge makes pressure distribution on the tongue to be more dispersed compare to that of conventional straight edge so that tonal noise was restrained.

Aerodynamic Performance of Blade Tip End-Plates Designed for Low-Noise Operation in Axial Flow Fans

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
Alessandro Corsini ◽  
Franco Rispoli ◽  
A. G. Sheard
Keyword(s):  
Flow Behavior ◽  
Acoustic Emissions ◽  
Axial Flow ◽  
Low Noise ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Leakage Flows ◽  
Blade Tip ◽  
Tip Leakage Flows

This study assesses the effectiveness of modified blade-tip configurations in achieving passive noise control in industrial fans. The concepts developed here, which are based on the addition of end-plates at the fan-blade tip, are shown to have a beneficial effect on the fan aeroacoustic signature as a result of the changes they induce in tip-leakage-flow behavior. The aerodynamic merits of the proposed blade-tip concepts are investigated by experimental and computational studies in a fully ducted configuration. The flow mechanisms in the blade-tip region are correlated with the specific end-plate design features, and their role in the creation of overall acoustic emissions is clarified. The tip-leakage flows of the fans are analyzed in terms of vortex structure, chordwise leakage flow, and loading distribution. Rotor losses are also investigated. The modifications to blade-tip geometry are found to have marked effects on the multiple vortex behaviors of leakage flow as a result of changes in the near-wall fluid flow paths on both blade surfaces. The improvements in rotor efficiency are assessed and correlated with the control of tip-leakage flows produced by the modified tip end-plates.

Investigation of Detailed Flow in a Variable Turbine Nozzle

2016 ◽  
Vol 33 (4) ◽  
Author(s):  
Yixiong Liu ◽  
Dazhong Lao ◽  
Ce Yang
Keyword(s):  
Flow Behavior ◽  
Suction Side ◽  
Main Stream ◽  
Leakage Flow ◽  
Pressure Side ◽  
Leakage Flows ◽  
Clearance Flow ◽  
Inlet Conditions ◽  
End Wall ◽  
Dynamics Method

AbstractThe detailed flow behavior of the nozzle channel of a variable turbine is presented in this paper. The numerical model of a variable nozzle turbine was developed by using computational fluid dynamics method, and validated by the measured performance data of the turbine. Two opening positions of the nozzle vane, as well as two inlet conditions of the nozzle representing different vane loadings, were investigated to evaluate the clearance flow behaviors. It is shown that the channel shock waves are produced at proper conditions, such as small opening and large inlet pressure, which has significant impact on the end wall clearance leakage flow. When the leakage flows through the end wall clearance from the pressure side to the suction side encountering by the main stream, and the leakage vortex is formed. It is found that this leakage vortex gradually enhanced from the trailing edge to the middle edge.

2703 High Performance Computing of Flow Field and Aerodynamic Noise for Centrifugal Fan of Air-conditioner

2013 ◽  
Vol 2013.26 (0) ◽  
pp. _2703-1_-_2703-2_
Author(s):  
Taku IWASE ◽  
Isao HAGIYA ◽  
Hideshi OBARA ◽  
Hiroyasu YONEYAMA ◽  
Yoshinobu YAMADE ◽  
...  
Keyword(s):  
Flow Field ◽  
High Performance Computing ◽  
High Performance ◽  
Aerodynamic Noise ◽  
Centrifugal Fan ◽  
Air Conditioner ◽  
Performance Computing

Influence of the Casing Width and the Impeller Position on Centrifugal Fan Performance: A CFD-Based Study on Cause and Effect

2014 ◽  
Author(s):  
S. Schönwald ◽  
F. Kameier ◽  
M. Böhle
Keyword(s):  
High Efficiency ◽  
Low Noise ◽  
Width Ratio ◽  
Centrifugal Fan ◽  
Noise Emission ◽  
Cfd Simulations ◽  
Fan Performance ◽  
Design Concepts ◽  
Impeller Outlet ◽  
Overall Efficiency

A high-efficiency centrifugal fan with low noise emission is used to investigate the influence of the casing width on the flow performance. Common design concepts use a width ratio of casing to impeller outlet from 2.5 up to 3. This range of the width ratio results in a large casing depth, which is not the best approach with regard to the overall dimension and the material costs for large industrial machines. Furthermore, centrifugal fan designs with a width ratio above 3 are disadvantageous because of their lower overall efficiency. In addition to an optimized casing depth, the position of the impeller in the casing also influences the performance. Using the results of several CFD simulations, we show that by creating a very small gap between the impeller rear plate and the casing wall, smaller energy losses and higher–performance can be achieved.

The Development of High Performance Centrifugal Compressor Using CFD and Other Considerations

2017 ◽  
Author(s):  
C. Xu ◽  
M. Muller
Keyword(s):  
Power Distribution ◽  
High Performance ◽  
High Efficiency ◽  
Low Noise ◽  
Field Application ◽  
Air Separation ◽  
Operating Range ◽  
Design Considerations ◽  
Reliable Design ◽  
Air Compression

Air compression is one of the most important processes of air separation. Reliable design, higher performance, low noise, no resonant frequencies in the operating range and economic to manufacture are the goals of compressor design. Although CFD has been widely used in the compressor designs, there are many design considerations need to be addressed during the design. In this paper, the detailed design considerations for compressor configuration, power distribution for each stage, and possible field application issues are discussed in detail. The aerodynamic and structural optimization using CFD and FEA are performed to obtain a high efficiency and wide operating range compressor stage with for robust operation. The new compressor development process addressed in this paper provides the basic design guidance for future new compressor development.

Study on Appropriate Diameter of Centrifugal Fan Surrounded by Heat Exchanger in Air Conditioner

2017 ◽  
Author(s):  
Daiwa Sato ◽  
T. Iwase ◽  
J. Xue ◽  
K. Tsuchihashi ◽  
H. Obara ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Standard Deviation ◽  
Pressure Drop ◽  
Velocity Distribution ◽  
Flow Distribution ◽  
Centrifugal Fan ◽  
Air Conditioner ◽  
Air Conditioners ◽  
Fan Performance

To meet the demand for energy-saving air conditioners, the pressure drop must be reduced and the air velocity distribution of the heat exchanger made uniform to improve the performance of both the fan and the heat exchange cycle. To investigate the effect of the fan on the pressure drop and the velocity distribution, we changed the fan diameter and fixed the shape of the heat exchanger. First, we investigated the fan by comparing the total pressure efficiency when the fan was mounted in an indoor unit and unmounted as a standalone fan. We found that the mounted fan performed worse than the standalone fan. The difference between these conditions was whether the heat exchanger was around the fan. Next, to determine the appropriate diameter, the performance of the mounted fan was evaluated by measuring its efficiency and the fan power. The diameter with the highest efficiency differed from the diameter with the lowest fan power. Because of this, the fan performance was strongly affected by the heat exchanger and the vortex. When the standard deviation of the air flow distribution in the heat exchanger was evaluated, the diameter with the lowest standard deviation was the same as the diameter with the lowest fan power. Since the standard deviation needs to be reduced to improve the performance of both the fan and the heat exchange cycle, the mounting conditions need to be considered to determine the fan shape. Thus, the flow field around the fan was visualized, and the velocity distributions for the investigated diameters were compared. We found the distance between the fan and the heat exchanger was an important factor determining the performance. A fan with the most appropriate diameter was prototyped to evaluate the fan performance. Results revealed it used 3% less power than a standard-diameter fan.

Performances of Water Jet Propulsion with PD Pump

2014 ◽  
Vol 602-605 ◽  
pp. 539-545
Author(s):  
You Sheng Yang ◽  
Peng Sun ◽  
Yang Fu ◽  
Chao Chao Zhao
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Low Noise ◽  
Water Jet ◽  
Speed Ratio ◽  
Jet Propulsion ◽  
Constant Flow Rate ◽  
Positive Displacement ◽  
Displacement Pump ◽  
Propulsion Unit

Water jet propulsion (WJP) with positive displacement pump (PD pump), in which the suction thrust of PD pump (Due to the effect of pump suction and the influence of the suction boundary layer) and the reaction thrust of water jet are used to push watercraft forward, has many advantages like high efficiency,low noise, high maneuverability, good adaptability to variable working conditions, simple transmission mechanism over traditional propulsion methods. A mathematical model is developed and the WJP theory with PD pump is analyzed. Numerical studies are carried out to study the suction thrust, reaction thrust, and propulsion efficiency of the thruster with Bernoullihyperbolic suction inlet-PD pump-Bernoulli hyperbolic nozzle. The results show that: 1) in the conditions of no cavitation in suction inlet and constant flow rate, the suction thrust is inversely proportional to the inlet diameter and reaches around 8.5% of the total thrust; 2) the reaction thrust increases with the decrease of the nozzle diameter; 3) the pump-suction coefficientvis proportional to the speed ratioμ; 4) the efficiency of WJP with PD pump is higher than with negative displacement pump under the same speed ratio. The related conclusions provide a basis for the design of high performance water propulsion unit.

Optimization of the Aerodynamic and Aeroacoustic Characteristics of a Small Centrifugal Fan by Means of Inverse Design and Evolutionary Algorithms

2020 ◽  
Author(s):  
Chris Eisenmenger ◽  
Stefan Frank ◽  
Paul Uwe Thamsen
Keyword(s):  
High Efficiency ◽  
Wide Frequency Range ◽  
Low Noise ◽  
Inverse Design ◽  
Centrifugal Fan ◽  
Test Rig ◽  
Design Code ◽  
Acoustic Characteristics ◽  
Ongoing Research ◽  
Wide Operating

Abstract In this work, the inverse design code TURBOdesign 1 has been used in a direct approach to optimize both the aerodynamic and aeroacoustic properties of a small centrifugal fan with backward-curved blades. Two promising fan designs along with a reference fan have been investigated numerically using CFD and the results have been validated experimentally using a chamber test rig for the aerodynamics and the in-duct method for acoustics. A design aiming for good aerodynamic performance showed an increased efficiency in a wide operating range of about 5 to 10%. Another design aiming for low noise showed a numerically determined reduction in the overall sound radiation of 1 dB on average. This trend could not be reproduced in the experiments, instead the high efficiency design showed the best acoustic characteristics in a wide frequency range, which is why this is a subject of ongoing research.

scholarly journals Reducing torque pulsations in PMa-SynRM: a way for improving motor performance

2021 ◽  
Vol 12 (1) ◽  
pp. 67
Author(s):  
Percy R. Viego ◽  
Julio R. Gómez ◽  
Vladimir Sousa ◽  
José P. Monteagudo Yanes ◽  
Enrique C. Quispe
Keyword(s):  
Permanent Magnets ◽  
High Efficiency ◽  
Torque Ripple ◽  
Operating Costs ◽  
Load Factor ◽  
Air Conditioner ◽  
Air Conditioners ◽  
Low Load ◽  
Torque Pulsations

This paper aims to evaluate the performance of synchronous reluctance motors assisted by a permanent magnet (PMa-SynRM) focused on efficiency and torque pulsations. PMa-SynRM shows high efficiency and power factor, compared to induction motors (IM), although they have a greater cost. These machines develop relatively high torque ripple, cogging torque, and torque imbalances. Consequently, the electromagnetic torque is reduced, the motor temperature is increased, and mechanical vibrations are induced. The optimal design of the machine structures such as flow barriers, permanent magnets, and stator slots, among others, allow reducing torque pulsations. A comparison is made between different designs of the PMa-SynRM reported in the scientific literature, and the effects on efficiency, torque pulsation, and operating costs are evaluated. A case study on the motor driving the air conditioner blower in a hotel room was made, to determine the best economic variant between IM or PMa-SynRM. A sensitive analysis was made to evaluate several uncertainties. The advantages of using one of the PMa-SynRM analyzed were demonstrated. Also, it was proved that the investment is feasible economically, although NPV and payback are not the best, due to low load factor in inverter-controlled motors in air conditioners.

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