摘要
使用CFD软件模拟横掠换热器管束中流体流动的换热特性,垂直于流动方向选取对称边界垂直流动非对称边界垂直流动、非对称边界非垂直流动三个边界条件分别来计算,结果表明:对比三种边界条件对应的Nu数,采取对称边界条件的简化计算是合理的;随着Re数的增加,整个区域的速度相图呈现出混沌状态,整体呈现鱼状的非线性特性;对不同管间距时横掠管束的温度场和流场进行非稳态数值模拟,对横竖排管间距相同,不同Re数时的Nu数进行求解,发现管间距越小,换热系数越高,紧凑型的管束布置方式在大Re数下,具有较好的换热能力,纵向间距比对换热能力的影响比横向间距要更强。
CFD software was used to simulate the heat transfer characteristics of the fluid flow in the tube bundle of the traversing heat exchanger. Three boundary conditions were selected to be perpendicular to the flow direction: symmetrical boundary vertical flow, asymmetrical boundary vertical flow, and asymmetrical boundary non-vertical flow. Results show that calculation assumption is reasonable to adopt the symmetry boundary condition perpendicular to the flow direction. The velocity phase diagram of entire region presents a chaotic state and the overall fish-like nonlinear characteristics with the increase of Reynolds number. Unsteady numerical simulations were conducted on the temperature and flow fields across tube bundle. Simulation results indicated thatthe smaller the tube spacing, the higher the heat transfer coefficient. At larger Reynolds number, the arrangement of compact tube bundle is beneficial to improve the performance of heat exchange. Longitudinal spacing has a better performance of heat exchange than horizontal spacing.
作者
袁尧
陈刚
YUAN Yao;CHEN Gang(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《能源工程》
2020年第6期57-63,67,共8页
Energy Engineering
关键词
对称边界
非垂直流动
非线性特性
换热系数
symmetric boundary
non-vertical flow
nonlinear characteristics
heat transfer coefficient