Small size axial flow fans are used as a cooling component for computers,electronic equipment and other electronic components.With the increasing power of electrical equipment,the demand for lower noise and higher ven...Small size axial flow fans are used as a cooling component for computers,electronic equipment and other electronic components.With the increasing power of electrical equipment,the demand for lower noise and higher ventilation of cooling fan is also increasing.Traditional methods of improving ventilation by raising the fan's rotation speed causes a decrease in efficiency and an increase in noise.In this paper,different structures of fans were simulated,and as a result,the counter-rotating fan can achieve higher pressure,efficiency and facilitate ventilation in a smaller space.Furthermore,some other conclusions are as follows:(1) Higher pressure rise can be obtained by a counter-rotating fan than by the two-stage rotor fan in the same axial length.Meanwhile,the counter-rotating fan has a broader work scope.(2) The main noise type of the counter-rotating fan is rotating noise;the small peak pulse caused by vortex noise mainly due to the eddy current produced by small eddies.(3) When the distance of counter-rotating fans is smaller than 2 times the chord,the greater distance the greater total pressure of the circum-averages and along the axial direction,the total pressure begin to decline until the distance is three times the chord,so there is an optimal distance between rotors.The simulation results are of important significance to the quantitative analysis and optimization design of the counter-rotating fan.展开更多
基金The author acknowledges the support of Zhejiang Provincial Natural Science Foundation (No.R107635)Zhejiang Provincial Key Science Foundation (2008 C11027)National Natural Science Foundation of China (No.50735004)
文摘Small size axial flow fans are used as a cooling component for computers,electronic equipment and other electronic components.With the increasing power of electrical equipment,the demand for lower noise and higher ventilation of cooling fan is also increasing.Traditional methods of improving ventilation by raising the fan's rotation speed causes a decrease in efficiency and an increase in noise.In this paper,different structures of fans were simulated,and as a result,the counter-rotating fan can achieve higher pressure,efficiency and facilitate ventilation in a smaller space.Furthermore,some other conclusions are as follows:(1) Higher pressure rise can be obtained by a counter-rotating fan than by the two-stage rotor fan in the same axial length.Meanwhile,the counter-rotating fan has a broader work scope.(2) The main noise type of the counter-rotating fan is rotating noise;the small peak pulse caused by vortex noise mainly due to the eddy current produced by small eddies.(3) When the distance of counter-rotating fans is smaller than 2 times the chord,the greater distance the greater total pressure of the circum-averages and along the axial direction,the total pressure begin to decline until the distance is three times the chord,so there is an optimal distance between rotors.The simulation results are of important significance to the quantitative analysis and optimization design of the counter-rotating fan.
文摘针对轴流通风机进行主动降噪,尚属于轴流通风机降噪领域的前沿问题.围绕该问题,以YBT-5.5型轴流通风机为试验对象,选取自由空间、对称分布受限空间、近壁面受限空间作为通风机试验环境,分析通风机集流区域的噪声分布,并对比了降噪前后的声压级、频谱特性.结果表明,集流区域正对方向,在自由空间下,降噪量可达7.2 dB(A);受限空间下,空间对称分布时降噪量为5.9 dB(A),近壁面处降噪量为2.8 dB(A).在通风机集流区域,对于斜向45°的测点,左侧降噪难度高于右侧;相较两侧的测点,左侧降噪难度低于右侧.当通风机位置从自由空间变为受限空间时,集流区域的噪声能量变化集中在100~500 Hz.
