Aeroacoustic performance of fans is essential due to their widespread application. Therefore, the original aim of this paper is to evaluate the generated noise owing to different geometric parameters. In current study...Aeroacoustic performance of fans is essential due to their widespread application. Therefore, the original aim of this paper is to evaluate the generated noise owing to different geometric parameters. In current study, effect of five geometric parameters was investigated on well performance of a Bladeless fan. Airflow through this fan was analyzed simulating a Bladeless fan within a 2 m×2 m×4 m room. Analysis of the flow field inside the fan and evaluating its performance were obtained by solving conservations of mass and momentum equations for aerodynamic investigations and FW-H noise equations for aeroacoustic analysis. In order to design Bladeless fan Eppler 473 airfoil profile was used as the cross section of this fan. Five distinct parameters, namely height of cross section of the fan, outlet angle of the flow relative to the fan axis, thickness of airflow outlet slit, hydraulic diameter and aspect ratio for circular and quadratic cross sections were considered. Validating acoustic code results, we compared numerical solution of FW-H noise equations for NACA0012 with experimental results. FW-H model was selected to predict the noise generated by the Bladeless fan as the numerical results indicated a good agreement with experimental ones for NACA0012. To validate 3-D numerical results, the experimental results of a round jet showed good agreement with those simulation data. In order to indicate the effect of each mentioned parameter on the fan performance, SPL and OASPL diagrams were illustrated.展开更多
The unique Coanda surface has a great influence on the performance of bladeless fan.However,there is few studies to explain the relationship between the performance and Coanda surface curvature at present.In order to ...The unique Coanda surface has a great influence on the performance of bladeless fan.However,there is few studies to explain the relationship between the performance and Coanda surface curvature at present.In order to gain a qualitative understanding of effect of the curvature on the performance of bladeless fan,numerical studies are performed in this paper.Firstly,three-dimensional numerical simulation is done by Fluent software.For the purpose to obtain detailed information of the flow field around the Coanda surface,two-dimensional numerical simulation is also conducted.Five types of Coanda surfaces with different curvature are designed,and the flow behaviour and the performance of them are analyzed and compared with those of the prototype.The analysis indicates that the curvature of Coanda surface is strongly related to blowing performance,It is found that there is an optimal curvature of Coanda surfaces among the studied models.Simulation result shows that there is a special low pressure region.With increasing curvature in Y direction,several low pressure regions gradually enlarged,then begin to merge slowly,and finally form a large area of low pressure.From the analyses of streamlines and velocity angle,it is found that the magnitude of the curvature affects the flow direction and reasonable curvature can induce fluid flow close to the wall.Thus,it leads to that the curvature of the streamlines is consistent with that of Coanda surface.Meanwhile,it also causes the fluid movement towards the most suitable direction.This study will provide useful information to performance improvements of bladeless fans.展开更多
针对无叶风扇气动噪声过大的问题,开展基于CST(Class Function/Shape Function Transformation,CST)参数化方法的柯恩达面气动噪声敏感性分析。首先,以NACA0012翼型及样条曲线构造柯恩达面,建立无叶风扇的风圈截面及三维模型。然后,通...针对无叶风扇气动噪声过大的问题,开展基于CST(Class Function/Shape Function Transformation,CST)参数化方法的柯恩达面气动噪声敏感性分析。首先,以NACA0012翼型及样条曲线构造柯恩达面,建立无叶风扇的风圈截面及三维模型。然后,通过数值模拟分析柯恩达面处的流动情况及气动噪声,并通过试验验证数值计算的准确性。最后,建立柯恩达面参数化模型,并以气动噪声为目标响应,采用Sobol法与Kriging代理模型相结合的方法,计算参数化模型中Bernstein多项式系数的一阶灵敏度系数和总灵敏度系数,找出对气动噪声影响较大的参数。结果表明,影响柯恩达面处气动噪声的主要因素依次为风圈截面的厚度、前缘半径、后缘厚度。展开更多
本文通过对IEC 60879:2019 Comfort fans and regulators for household and purposes-Methods for measuring performance《家用和类似用途舒适风扇 性能测试方法》中关于无叶风扇调速比试验方法的进行研究,分析对无叶风扇调速比方法...本文通过对IEC 60879:2019 Comfort fans and regulators for household and purposes-Methods for measuring performance《家用和类似用途舒适风扇 性能测试方法》中关于无叶风扇调速比试验方法的进行研究,分析对无叶风扇调速比方法的影响因素。针对其主要影响因素,探讨无叶风扇调速比试验方法相应优化改进措施与方案,提高相关试验结果的准确性与可复现性。展开更多
A patent is a kind of technical document to protect intellectual property for individuals or enterprises. Patentable idea generation is a crucial step for patent application and analogy is confirmed to be an effective...A patent is a kind of technical document to protect intellectual property for individuals or enterprises. Patentable idea generation is a crucial step for patent application and analogy is confirmed to be an effective technique to inspire creative ideas. Analogy?based design usually starts from representation of an analogy source and is followed by the retrieval of appropriate analogs, mapping of design knowledge and adaptation of target solution. To diffuse one core idea into other new contexts and achieve more patentable ideas, this paper mainly centered on the first two stages of analogy?based design and proposed a patentable ideation framework. The analogical information of the source system, including source design problems and solution, was mined comprehensively through International Patent Classification analysis and represented in the form of function, behavior and structure. Three heuristics were suggested for searching the set of candidate target systems with a similar design problem, where the source design could be transferred. To systematize the process of source representation, analogs retrieval, idea transfer, and solution generation, an ideation model was put forward. Finally, the bladeless fan was selected as a source design to illustrate the application of this work. The design output shows that the representation and heuristics are beneficial, and this systematic ideation method can help the engineer or designer enhance creativity and discover more patentable opportunities.展开更多
文摘Aeroacoustic performance of fans is essential due to their widespread application. Therefore, the original aim of this paper is to evaluate the generated noise owing to different geometric parameters. In current study, effect of five geometric parameters was investigated on well performance of a Bladeless fan. Airflow through this fan was analyzed simulating a Bladeless fan within a 2 m×2 m×4 m room. Analysis of the flow field inside the fan and evaluating its performance were obtained by solving conservations of mass and momentum equations for aerodynamic investigations and FW-H noise equations for aeroacoustic analysis. In order to design Bladeless fan Eppler 473 airfoil profile was used as the cross section of this fan. Five distinct parameters, namely height of cross section of the fan, outlet angle of the flow relative to the fan axis, thickness of airflow outlet slit, hydraulic diameter and aspect ratio for circular and quadratic cross sections were considered. Validating acoustic code results, we compared numerical solution of FW-H noise equations for NACA0012 with experimental results. FW-H model was selected to predict the noise generated by the Bladeless fan as the numerical results indicated a good agreement with experimental ones for NACA0012. To validate 3-D numerical results, the experimental results of a round jet showed good agreement with those simulation data. In order to indicate the effect of each mentioned parameter on the fan performance, SPL and OASPL diagrams were illustrated.
基金supported by National Natural Science Foundation of China(No.51276172)National Science and TechnologySupport Project(No.2013BAF05B01)
文摘The unique Coanda surface has a great influence on the performance of bladeless fan.However,there is few studies to explain the relationship between the performance and Coanda surface curvature at present.In order to gain a qualitative understanding of effect of the curvature on the performance of bladeless fan,numerical studies are performed in this paper.Firstly,three-dimensional numerical simulation is done by Fluent software.For the purpose to obtain detailed information of the flow field around the Coanda surface,two-dimensional numerical simulation is also conducted.Five types of Coanda surfaces with different curvature are designed,and the flow behaviour and the performance of them are analyzed and compared with those of the prototype.The analysis indicates that the curvature of Coanda surface is strongly related to blowing performance,It is found that there is an optimal curvature of Coanda surfaces among the studied models.Simulation result shows that there is a special low pressure region.With increasing curvature in Y direction,several low pressure regions gradually enlarged,then begin to merge slowly,and finally form a large area of low pressure.From the analyses of streamlines and velocity angle,it is found that the magnitude of the curvature affects the flow direction and reasonable curvature can induce fluid flow close to the wall.Thus,it leads to that the curvature of the streamlines is consistent with that of Coanda surface.Meanwhile,it also causes the fluid movement towards the most suitable direction.This study will provide useful information to performance improvements of bladeless fans.
文摘针对无叶风扇气动噪声过大的问题,开展基于CST(Class Function/Shape Function Transformation,CST)参数化方法的柯恩达面气动噪声敏感性分析。首先,以NACA0012翼型及样条曲线构造柯恩达面,建立无叶风扇的风圈截面及三维模型。然后,通过数值模拟分析柯恩达面处的流动情况及气动噪声,并通过试验验证数值计算的准确性。最后,建立柯恩达面参数化模型,并以气动噪声为目标响应,采用Sobol法与Kriging代理模型相结合的方法,计算参数化模型中Bernstein多项式系数的一阶灵敏度系数和总灵敏度系数,找出对气动噪声影响较大的参数。结果表明,影响柯恩达面处气动噪声的主要因素依次为风圈截面的厚度、前缘半径、后缘厚度。
文摘本文通过对IEC 60879:2019 Comfort fans and regulators for household and purposes-Methods for measuring performance《家用和类似用途舒适风扇 性能测试方法》中关于无叶风扇调速比试验方法的进行研究,分析对无叶风扇调速比方法的影响因素。针对其主要影响因素,探讨无叶风扇调速比试验方法相应优化改进措施与方案,提高相关试验结果的准确性与可复现性。
基金support of the National Natural Science Foundation(Grant No.51675159)Human Resource and Social Security Project of Hebei Province(No.JRS-2016-3097)
文摘A patent is a kind of technical document to protect intellectual property for individuals or enterprises. Patentable idea generation is a crucial step for patent application and analogy is confirmed to be an effective technique to inspire creative ideas. Analogy?based design usually starts from representation of an analogy source and is followed by the retrieval of appropriate analogs, mapping of design knowledge and adaptation of target solution. To diffuse one core idea into other new contexts and achieve more patentable ideas, this paper mainly centered on the first two stages of analogy?based design and proposed a patentable ideation framework. The analogical information of the source system, including source design problems and solution, was mined comprehensively through International Patent Classification analysis and represented in the form of function, behavior and structure. Three heuristics were suggested for searching the set of candidate target systems with a similar design problem, where the source design could be transferred. To systematize the process of source representation, analogs retrieval, idea transfer, and solution generation, an ideation model was put forward. Finally, the bladeless fan was selected as a source design to illustrate the application of this work. The design output shows that the representation and heuristics are beneficial, and this systematic ideation method can help the engineer or designer enhance creativity and discover more patentable opportunities.
