非均匀热流边界条件下螺旋管内流动传热的场协同分析

Fields synergy analysis of turbulent heat transfer in helically coiled tube with non-uniform surface heat flux

建立了螺旋管内流动换热的物理数学模型,对均匀和非均匀热流边界条件下螺旋管内湍流传热进行了数值模拟。结果表明:当对螺旋管表面施加相同的加热功率时,均匀热流边界条件下湍流传热系数高于非均匀热流边界条件下的湍流传热系数,且均匀热流边界条件下螺旋管内的场协同角低于非均匀热流边界条件;非均匀热流边界条件时,在相同的De下,曲率较小的螺旋管传热系数大,且曲率较小的螺旋管内场协同角较小;同时,随着管径的增大,螺旋管内的传热系数也随之下降,但螺旋管内的场协同角随之增大。

Physical and mathematic models of fluid flow and heat transfer in helically coiled tube are established, and numerical simulations of the turbulent heat transfer in helically coiled tube are performed under the uniform and non-uniform heat flux boundary conditions.The results show that,when the same heating power is exerted to the helically coiled tube surface,the turbulent heat transfer coefficient of the uniform heat flux boundary is higher than that with non-uniform heat flux boundary,and the fields synergy angle of the uniform heat flux boundary is less than that with non-uniform heat flux boundary.Meanwhile,the turbulent heat transfer coefficient of small curvature is higher with the same Dean number under non-uniform heat flux boundary while the fields synergy angle is smaller.With the increase of the tube diameter,heat transfer coefficient in helically-coiled tube declines while the fields synergy angle raises.