摘要
现代水力机械叶片设计时采用的翼型大多为空气动力学翼型,而较少关注水流场与空气流场的差异及流质改变对翼型流动特性的影响,因此选取七种翼型,基于CFD软件,在高雷诺数、小攻角下,对翼型在水、空气两种流场中绕流的升阻力、表面涡量分布、速度场进行二维数值模拟计算,并分析了两种流场中的差异,提出了水、空气两种流场中升力、阻力系数的差异修正系数,推导了以水(气)流场试验数据表达的相同条件下气(水)流场运动方程。结果表明,气流场、水流场的差异对翼型升力系数的影响较小,对阻力系数及升阻比的影响较大;水流场中,翼型表面涡量不存在较大波动,分布更为均匀稳定,且分离点位置集中于翼型中段;水、空气流场的尾流低速区域面积之比能够较好地反映阻力系数的差异修正系数。研究成果可用于指导不同流场中的翼型设计。
Most of the airfoils used in the design of modern hydraulic machinery blades are aerodynamic airfoils,but less attention is paid to the difference between water and air flow filed,and the impact of the change of fluid on the flow characteristics of airfoils.Therefore,seven airfoils are selected as the research objects.Based on CFD software,the lift resistance and surface vorticity distribution of airfoils in water and air flow fields are studied under conditions of high Reynolds number and small angle of attack.Two-dimensional numerical simulation of velocity field is carried out,and the difference between the two flow fields is analyzed.The difference correction coefficients of lift and drag coefficients in water and air flow fields are proposed.The motion equation of air(water)flow field under the same conditions expressed by experimental data of water(air)flow field is derived.The results show that the difference of airflow field and water flow field has little impact on lift coefficient,but has great impact on drag coefficient and lift-drag ratio.In water flow field,the surface vorticity of airfoil does not fluctuate greatly,its distribution is more uniform and stable,and the separation point is concentrated in the middle of airfoil.The ratio of wake area to air area can better reflect the difference correction of drag coefficient.The results can be used to guide airfoil design in different flow fields.
作者
石乘帆
宋文武
SHI Cheng-fan;SONG Wen-wu(School of Energy and Power Engineering, Xihua University, Chengdu 610039, China;Key Laboratory of Fluid and Power Machinery,Ministry of Education, Xihua University, Chengdu 610039, China)
出处
《水电能源科学》
北大核心
2019年第7期132-136,共5页
Water Resources and Power
基金
四川省科技厅项目(2016JY0187)
四川省教育厅重大培育项目(12CZ013)
西华大学流体及动力机械教育部重点实验室开放基金资助项目(szjj2015-037)
西华大学研究生创新基金(ycjj2019042)
关键词
翼型
气-水流场
升力系数
阻力系数
修正
airfoil
multi flow field
lift coefficient
resistance coefficient
correction
