前置导叶对畜禽舍轴流风机性能的影响

Influence of inlet guide vane on the performance of axial fan for livestock and poultry farming

畜禽养殖过滤除臭装置对传统轴流风机负压抽吸能力提出了更高的要求。为提高传统轴流风机的气动性能,扩大其有效工作区间,该研究以550型农用轴流风机为对象,结合试验和数值模拟研究了前置导叶对轴流风机性能的影响。通过单因素和响应面分析方法,对前置导叶的导叶安装角(α)、轴向间距(L)、导叶个数(n)对风机性能和流场的影响进行研究,分析各因素对风机性能的影响,求解出最佳参数组合。通过3D打印制作前置导叶并进行样机试验。结果表明,增设前置导叶后,风机内部区域涡流得到削弱,降低了流动损失,静压效率提高,流动剧烈程度降低,流场更稳定,叶片静压差增大,风机叶片的做功能力增强,与传统结构相比,增设前置导叶后风机通风量和能效比均明显提升,通风量提升幅度在5.7%~10.39%,能效比提升幅度在6.62%~10.89%;在静压50 Pa下,通风量提升6.76%,能效比提升7.75%。研究结果证明了增设前置导叶提升轴流风机负压抽吸能力的可行性。

Higher capacity of negative pressure suction has been required in the traditional agricultural axial fan,particularly with the increase of filtration and deodorization devices in livestock and poultry farming.This study aims to improve the aerodynamic performance of agricultural axial fans,and then to expand their working range.A common type-550 axial fan was taken as the research object.The inlet guide vanes were added under the experiments and numerical simulations.The single factor and response surface analysis were selected to investigate the effects of guide vane installation angle(α),axial distance(L),and number of guide vane(n)on the fan performance and flow field.The influence of each factor on the performance of the fan was then obtained,according to the response surface analysis.The best combination of installation parameters was achieved for the better performance of the axial fan.A series of 3D-printed fan and tunnel experiments were carried out to verify the best combination of installation parameters of inlet guide vanes.Numerical simulation results showed the improved performance was represented by four perspectives after the addition of the inlet guide vane.Firstly,the inlet guide vane was adjusted to a suitable installation angle.After that,the meridian plane axial velocity increased significantly to black the leakage vortex extension to the inlet.As such,the static pressure efficiency was improved,due to the weak internal vortex,and the reduced flow loss.Secondly,the inlet guide vane was adjusted to a suitable installation distance.The fully pre-rotating was found in the inlet flow of the high span,leading to a more uniform flow in the axial flow fan.Thirdly,a suitable number of blades was set in the inlet guide vane.There was a decrease in the intensity of flow change in the inner channel of the axial flow fan,indicating a more stable flow field.Finally,there was an increase in the static pressure difference at the limit position of the blade pressure surface and suction surface,particularly with the higher working capacity of the fan blade.The better performance was achieved with an guide vane mounting angle of−25°to−15°,axial distance of 57 to 81mm,and a number of guide vane of 4 to 6.Specifically,the installation parameters were obtained with the guide vane mounting angleα=−21°,the axial distance L=57 mm,and the number of guide vane n=4.These optimal parameters were used for the installation of the 3Dprinted inlet guide vane on the fan.Tunnel experiments showed that the ventilation volume and energy efficiency ratio of the modified fan were significantly improved after adding the inlet guide vane,where the ventilation volume increased from 5.7%to 10.39%,and the energy efficiency ratio increased from 6.62%to 10.89%in the fan performance test.Furthermore,the ventilation volume and energy efficiency ratio increased by 6.76%and 7.75%,respectively,under the working condition of 50 Pa.Consequently,the addition of inlet guide vanes can be expected to enhance the negative pressure suction capacity of agricultural axial flow fans.