Losses in channel flows are usually determined using a frictional head loss parameter. Fluid friction is however not the only source of loss in channel flows with heat transfer. For such flow problems, thermal energy ...Losses in channel flows are usually determined using a frictional head loss parameter. Fluid friction is however not the only source of loss in channel flows with heat transfer. For such flow problems, thermal energy degradation, in addition to mechanical energy degradation, add to the total loss in thermodynamic head. To assess the total loss in a channel with combined convection and radiation heat transfer, the conventional frictional head loss parameter is extended in this study. The analysis is applied to a 3D turbulent channel flow and identifies the critical locations in the flow domain where the losses are concentrated. The influence of Boltzmann number is discussed, and the best channel geometry for flows with combined heat transfer modes is also determined.展开更多
To reduce the time of getting an ideal elliptical heat used in power station through repairing and testing a die repeatedly according to experience,finite element software Deform-3D was used to research the simulation...To reduce the time of getting an ideal elliptical heat used in power station through repairing and testing a die repeatedly according to experience,finite element software Deform-3D was used to research the simulation of deformation-heat transfer coupling in hot forming process of elliptical head with the size of Φ1200 mm ×100 mm. The variations of stress,stain,temperature,thickness and strain rate in forming process were gotten,and the forming quality was evaluated from roundness,thinning rate and thermal contraction. The results show that the maximum thinning rate of the elliptical head is 7. 31% ,it is close to the orthographic place; and the inner diam- eter obtained from simulation is 1200. 6 - 1202. 977 mm,it is in the range of inner diameter tolerance required; all the data fit well with the practical dimension data of processing head.展开更多
个性化的头相关传输函数(Head Related Transfer Function,HRTF)对于虚拟听觉技术的实现至关重要。然而在具体的应用过程中,测量每一位受试者的个性化HRTF较为繁琐,为此文章提出一种基于加权弹性网络回归的算法,只需获取受试者的生理参...个性化的头相关传输函数(Head Related Transfer Function,HRTF)对于虚拟听觉技术的实现至关重要。然而在具体的应用过程中,测量每一位受试者的个性化HRTF较为繁琐,为此文章提出一种基于加权弹性网络回归的算法,只需获取受试者的生理参数即可获得HRTF的个性化幅度响应。首先通过数据库中的受试者数据,根据生理参数与幅度的相关性计算获得生理参数的权值,并将权值加入到同时含有1范数和2范数的弹性网络回归中,以此来获取新受试者的生理参数稀疏系数;最后将所得稀疏系数与数据库中的HRTF幅度结合就可以得到新受试者的个性化幅度响应。结果表明,文中方法对于个性化HRTF幅度的合成有较好的效果,尤其是在中低频段内准确度较高。展开更多
文摘Losses in channel flows are usually determined using a frictional head loss parameter. Fluid friction is however not the only source of loss in channel flows with heat transfer. For such flow problems, thermal energy degradation, in addition to mechanical energy degradation, add to the total loss in thermodynamic head. To assess the total loss in a channel with combined convection and radiation heat transfer, the conventional frictional head loss parameter is extended in this study. The analysis is applied to a 3D turbulent channel flow and identifies the critical locations in the flow domain where the losses are concentrated. The influence of Boltzmann number is discussed, and the best channel geometry for flows with combined heat transfer modes is also determined.
基金Sponsored by the Heilongjiang Provincial Public Relation Project (Grant No.GC06A515)
文摘To reduce the time of getting an ideal elliptical heat used in power station through repairing and testing a die repeatedly according to experience,finite element software Deform-3D was used to research the simulation of deformation-heat transfer coupling in hot forming process of elliptical head with the size of Φ1200 mm ×100 mm. The variations of stress,stain,temperature,thickness and strain rate in forming process were gotten,and the forming quality was evaluated from roundness,thinning rate and thermal contraction. The results show that the maximum thinning rate of the elliptical head is 7. 31% ,it is close to the orthographic place; and the inner diam- eter obtained from simulation is 1200. 6 - 1202. 977 mm,it is in the range of inner diameter tolerance required; all the data fit well with the practical dimension data of processing head.
文摘个性化的头相关传输函数(Head Related Transfer Function,HRTF)对于虚拟听觉技术的实现至关重要。然而在具体的应用过程中,测量每一位受试者的个性化HRTF较为繁琐,为此文章提出一种基于加权弹性网络回归的算法,只需获取受试者的生理参数即可获得HRTF的个性化幅度响应。首先通过数据库中的受试者数据,根据生理参数与幅度的相关性计算获得生理参数的权值,并将权值加入到同时含有1范数和2范数的弹性网络回归中,以此来获取新受试者的生理参数稀疏系数;最后将所得稀疏系数与数据库中的HRTF幅度结合就可以得到新受试者的个性化幅度响应。结果表明,文中方法对于个性化HRTF幅度的合成有较好的效果,尤其是在中低频段内准确度较高。
