In order to study the relationship between the important parameters of internal flow and the effect of drag and noise reduction,the internal flow field and sound field characteristics of bionic centrifugal pump are st...In order to study the relationship between the important parameters of internal flow and the effect of drag and noise reduction,the internal flow field and sound field characteristics of bionic centrifugal pump are studied in this paper.Based on the methods of theoretical analysis,numerical simulation and test,the relationship between wall average shear stress,drag reduction rate,increasing efficiency and noise reduction rate of internal sound field is studied.Internal flow parameters to judge and predict the effect of drag and noise reduction are revealed.The results show that the bionic pit can effectively increase the thickness of the boundary layer and reduce the Reynolds stress on the wall.The resistance on the wall is reduced and the hydraulic efficiency of the centrifugal pump is increased.The noise reduction rate is basically consistent with the changing trend of the drag reduction rate,increasing efficiency and wall average shear stress in the flow field.Wall average shear stress can reveal the effect of drag and noise reduction,so the effect of drag and noise reduction can be predicted and judged by the change of wall average shear stress.展开更多
In this paper, a bionic method was presented to improve the erosion resistance of blade of the centrifugal fan. A numerical investigation of the solid particle erosion on the standard and bionic configuration blade of...In this paper, a bionic method was presented to improve the erosion resistance of blade of the centrifugal fan. A numerical investigation of the solid particle erosion on the standard and bionic configuration blade of 4-72N_o10C centrifugal fan was presented. The numerical study employs computational fluid dynamics （CFD） software, based on a finite volume method, in which the discrete phase model was used to modele the solid particles flow, and the Eulerian conservation equation was adopt to simulate the continuous phase. Moreover, user-defined function was used to define wear equation. The various diameters of the particles were taken into account. The positions of collision of standard and bionic fan blades were discussed, and two kinds of centrifugal fan blade wear were compared. The results show that the particles from the incident source with different positions have different processes of turning and movement when enter into the impeller. The trajectories of flow in the fan channel are significantly different for the particles with different diameters. Bionic fan blade have lower erosion rate than the standard fan blade when the particle size is 20 μm. The anti-erosion mechanism of the bionic fan blade was discussed.展开更多
Unlike most animals,plants fail to move bodily at will.However,movements also occur in every single part of plants out of energy and nutrients needs,spanning from milliseconds to hours on a time scale.And with the gro...Unlike most animals,plants fail to move bodily at will.However,movements also occur in every single part of plants out of energy and nutrients needs,spanning from milliseconds to hours on a time scale.And with the growing understanding of plant movement in the academic community,bionic soft robots based on plant movement principles are increasingly studied and are considered by scientists as a source of inspiration for innovative engineering solutions.In this paper,through the study of the biological morphology,microstructure,and motion mechanism of the flytrap,we developed chambered design rules,and designed and fabricated a gas-driven bionic flytrap blade,intending to investigate its feasibility of performing complex bending deformation.The experimental result shows that the bionic flytrap blade can achieve multi-dimensional bending deformation,and complete the bending and closing action within 2 s.The performance of the bionic flytrap blade fabricated is in high agreement with the real flytrap blade in terms of bending and deformation,achieving an excellent bionic design effect.In this study,the chambered design rules of the bionic flytrap blade were proposed and developed,and the possibility of its deformation was investigated.The effects of different chamber types and different flow channel design precepts on the bending deformation of the bionic flytrap blade were revealed,together with the relationship between the response time and flow rate of the bionic flytrap blade.At last,this study provides new ideas for the study of plant blade motion mechanism in a hope to expand the application fields of bionic robots,especially hope to offer solutions for plant-type robotics.展开更多
基金This work was supported by National Natural Science Foundation of China(Nos.51879122,51579117 and 51779106)National Key Research and Development Program of China(Nos.2016YFB0200901 and 2017YFC0804107)+4 种基金Zhenjiang key research and development plan(Nos.GY2017001and GY2018025)the Open Research Subject of Key Labo-ratory of Fluid and Power Machinery,Ministry of Education,Xihua University(Nos.szjj2017-094 and szijj2016-068)Sichuan Provincial Key Lab of Process Equipment and Control(Nos.GK201614 and GK201816)Jiangsu University Young Talent training Program-Outstanding Young backbone Teacher,Program Development of Jiangsu Higher Education Institutions(PAPD)Jiangsu top six talent summitproject(GDZB-017).
文摘In order to study the relationship between the important parameters of internal flow and the effect of drag and noise reduction,the internal flow field and sound field characteristics of bionic centrifugal pump are studied in this paper.Based on the methods of theoretical analysis,numerical simulation and test,the relationship between wall average shear stress,drag reduction rate,increasing efficiency and noise reduction rate of internal sound field is studied.Internal flow parameters to judge and predict the effect of drag and noise reduction are revealed.The results show that the bionic pit can effectively increase the thickness of the boundary layer and reduce the Reynolds stress on the wall.The resistance on the wall is reduced and the hydraulic efficiency of the centrifugal pump is increased.The noise reduction rate is basically consistent with the changing trend of the drag reduction rate,increasing efficiency and wall average shear stress in the flow field.Wall average shear stress can reveal the effect of drag and noise reduction,so the effect of drag and noise reduction can be predicted and judged by the change of wall average shear stress.
基金supported by National Natural Science Foundation of China (Nos. 51175220 and 51205161)Specialized Research Fund for the Doctoral Program of Higher Education (No. 20100061110023)+3 种基金the Projects of Cooperation and Innovation to National Potential Oil and Gas for Production and Research (No. OSR-04-04)China Postdoctoral Science Foundation (No. 2012M511345)Ten Outstanding Youth Fund Project of Jilin University(No. 200905016)Basic Scientific Research Expenses of Project of Jilin University (No. 450060481176)
文摘In this paper, a bionic method was presented to improve the erosion resistance of blade of the centrifugal fan. A numerical investigation of the solid particle erosion on the standard and bionic configuration blade of 4-72N_o10C centrifugal fan was presented. The numerical study employs computational fluid dynamics （CFD） software, based on a finite volume method, in which the discrete phase model was used to modele the solid particles flow, and the Eulerian conservation equation was adopt to simulate the continuous phase. Moreover, user-defined function was used to define wear equation. The various diameters of the particles were taken into account. The positions of collision of standard and bionic fan blades were discussed, and two kinds of centrifugal fan blade wear were compared. The results show that the particles from the incident source with different positions have different processes of turning and movement when enter into the impeller. The trajectories of flow in the fan channel are significantly different for the particles with different diameters. Bionic fan blade have lower erosion rate than the standard fan blade when the particle size is 20 μm. The anti-erosion mechanism of the bionic fan blade was discussed.
基金the National Natural Science Foundation of China,51905084the Natural Science Foundation of Heilongjiang Province,YQ2021E002.
文摘Unlike most animals,plants fail to move bodily at will.However,movements also occur in every single part of plants out of energy and nutrients needs,spanning from milliseconds to hours on a time scale.And with the growing understanding of plant movement in the academic community,bionic soft robots based on plant movement principles are increasingly studied and are considered by scientists as a source of inspiration for innovative engineering solutions.In this paper,through the study of the biological morphology,microstructure,and motion mechanism of the flytrap,we developed chambered design rules,and designed and fabricated a gas-driven bionic flytrap blade,intending to investigate its feasibility of performing complex bending deformation.The experimental result shows that the bionic flytrap blade can achieve multi-dimensional bending deformation,and complete the bending and closing action within 2 s.The performance of the bionic flytrap blade fabricated is in high agreement with the real flytrap blade in terms of bending and deformation,achieving an excellent bionic design effect.In this study,the chambered design rules of the bionic flytrap blade were proposed and developed,and the possibility of its deformation was investigated.The effects of different chamber types and different flow channel design precepts on the bending deformation of the bionic flytrap blade were revealed,together with the relationship between the response time and flow rate of the bionic flytrap blade.At last,this study provides new ideas for the study of plant blade motion mechanism in a hope to expand the application fields of bionic robots,especially hope to offer solutions for plant-type robotics.
文摘为了研究立式管道泵内部声场特性,减少管道泵运行时的噪声,基于CFD+Lighthill声类比理论对管道泵内部流场与声场进行仿真求解,并借鉴猫头鹰羽毛端部锯齿结构进行仿生优化,以期达到降噪目标。针对0.8Qd、Qd及1.2Qd3个运行工况,选用RNG k-ε模型分别对立式管道泵进行非定常数值模拟,获得3个工况下管道泵内部压力脉动数据。提取非定常计算所得的脉动力,导入声学软件LMS Virtual.lab中进行声场计算,得到各工况下管道泵进、出口声压级、泵体内部的声压分布及主要噪声源分布。结果表明:管道泵内部流动诱导噪声与压力脉动密切相关,主要是由叶轮与泵体的动静干涉引起,其频率特性与压力脉动相似,声压分布集中在轴频、叶频及其倍频,叶频时声压级最大。流量越大,管道泵进、出口声压级越大。基于仿生学原理,参考猫头鹰体表覆羽样本利用相似准则设计仿生锯齿叶片,展开仿生降噪研究,选择齿距、齿宽、齿高3个因素,设计了16组正交试验模型,计算得到各工况下泵内部流场和声场数据。选取最优降噪模型与原模型进行对比分析,结果表明:仿生叶片尾缘锯齿结构能够起到降低压力脉动、稳定流场、降低噪声的作用,其中设计工况下噪声降幅明显,叶频处噪声降低8 d B。
