以NACA0012翼型和某型飞机翼型为研究对象,采用边界层积分法计算了翼型表面的局部对流换热系数(Local Heat Transfer Coefficient),研究了飞行迎角、来流马赫数、来流静温、MVD、LWC对LHTC的影响。研究发现,随着各项参数的变化,LHTC的...以NACA0012翼型和某型飞机翼型为研究对象,采用边界层积分法计算了翼型表面的局部对流换热系数(Local Heat Transfer Coefficient),研究了飞行迎角、来流马赫数、来流静温、MVD、LWC对LHTC的影响。研究发现,随着各项参数的变化,LHTC的变化具有一定规律,无法拟合出合理的曲线表征各参数对LHTC的影响,曲线簇表征各参数对LHTC的影响缺乏翼型通用性。展开更多
The present work experimentally and numerically investigates the local heat transfer enhancement induced by a piezoelectric fan interacting with a cross flow in a local heated channel.The piezoelectric fan is placed a...The present work experimentally and numerically investigates the local heat transfer enhancement induced by a piezoelectric fan interacting with a cross flow in a local heated channel.The piezoelectric fan is placed along the flow direction and tested under different amplitudes and flow rates.In the simulations,a spring-based smoothing method and a local remeshing technique are used to handle the moving boundary problems.Hybrid mesh is used to reduce the size of dynamic mesh domain and to improve computational efficiency.The experimental and numerical values of the time-averaged mean Nusselt number are found to be in good agreement,with deviations of less than 10%.The experimental result shows that the heat transfer performance of the heated surfaces is substantially enhanced with a vibrating piezoelectric fan.The numerical result shows that the heat transfer enhancement comes from the strong longitudinal vortex pairs generated by the piezoelectric fan,which significantly promote heat exchange between the main flow and the near-wall flow.In the case of a=0.66(a is the dimensionless amplitude)and Re=1820,the enhancement ratio of the time-averaged mean Nusselt number reaches 119.9%.展开更多
Laminar natural convection heat transfer inside air-filled, rectangular enclosures partially heated from below and cooled at one side is studied numerically. A computational code based on the SIMPLE-C algorithm is use...Laminar natural convection heat transfer inside air-filled, rectangular enclosures partially heated from below and cooled at one side is studied numerically. A computational code based on the SIMPLE-C algorithm is used for the solution of the system of the mass, momentum, and energy transfer governing equations. Simulations are performed for a complete range of heater size, for Rayleigh numbers based on the height of the cavity ranging from 10~3to 10~6, and for height-to-width aspect ratios of the cavity spanning from 0.25 to 4. It is found that the heat transfer rate increases with increasing the heater size and the Rayleigh number, while it decreases with increasing the aspect ratio of the cavity. Dimensionless heat transfer correlations are also proposed.展开更多
文摘以NACA0012翼型和某型飞机翼型为研究对象,采用边界层积分法计算了翼型表面的局部对流换热系数(Local Heat Transfer Coefficient),研究了飞行迎角、来流马赫数、来流静温、MVD、LWC对LHTC的影响。研究发现,随着各项参数的变化,LHTC的变化具有一定规律,无法拟合出合理的曲线表征各参数对LHTC的影响,曲线簇表征各参数对LHTC的影响缺乏翼型通用性。
基金Project supported by the National Natural Science Foundation of China(Nos.51575487 , 51875521)。
文摘The present work experimentally and numerically investigates the local heat transfer enhancement induced by a piezoelectric fan interacting with a cross flow in a local heated channel.The piezoelectric fan is placed along the flow direction and tested under different amplitudes and flow rates.In the simulations,a spring-based smoothing method and a local remeshing technique are used to handle the moving boundary problems.Hybrid mesh is used to reduce the size of dynamic mesh domain and to improve computational efficiency.The experimental and numerical values of the time-averaged mean Nusselt number are found to be in good agreement,with deviations of less than 10%.The experimental result shows that the heat transfer performance of the heated surfaces is substantially enhanced with a vibrating piezoelectric fan.The numerical result shows that the heat transfer enhancement comes from the strong longitudinal vortex pairs generated by the piezoelectric fan,which significantly promote heat exchange between the main flow and the near-wall flow.In the case of a=0.66(a is the dimensionless amplitude)and Re=1820,the enhancement ratio of the time-averaged mean Nusselt number reaches 119.9%.
文摘Laminar natural convection heat transfer inside air-filled, rectangular enclosures partially heated from below and cooled at one side is studied numerically. A computational code based on the SIMPLE-C algorithm is used for the solution of the system of the mass, momentum, and energy transfer governing equations. Simulations are performed for a complete range of heater size, for Rayleigh numbers based on the height of the cavity ranging from 10~3to 10~6, and for height-to-width aspect ratios of the cavity spanning from 0.25 to 4. It is found that the heat transfer rate increases with increasing the heater size and the Rayleigh number, while it decreases with increasing the aspect ratio of the cavity. Dimensionless heat transfer correlations are also proposed.
