中文摘要：

螺旋通道是提高流体传热及传质效率的重要结构,以其节省空间及易于加工的特点被广泛应用.而通道内流体的流动和传热特性作为评价螺旋通道的重要性质,对其实际应用具有重要的指导意义,成为近年来的研究热点.而研究重点主要集中在螺旋通道的结构参数和流动工质两个方面,本文对螺旋通道内流体流动与传热特性研究进行综述,总结了螺旋通道结构及流动工质对其性能的影响规律;具体分析了螺旋通道直径、管径、螺距、截面形状等结构参数以及流动工质种类、浓度等物性参数对其传热系数和流动阻力的影响;对比了层流及湍流状态下实验和数值模拟结论;为螺旋通道结构优化及工质选取提供了参考,并且展望了螺旋通道内流体流动及传热特性研究的发展趋势.

英文摘要：

As an important structure to improve the efficiency of heat transfer and mass transfer,helical channel has been widely used in the application fields of power generation,refrigeration,chemical reaction,heat recovery,food processing and material mixing because of its compact structure and easy processing.Different from the straight channel,helical channel can produce the secondary flow perpendicular to the axial flow direction,which can increase the disturbance of the fluid flowing in the channel,and then reduce the thickness of the boundary layer,and enhance the heat transfer characteristics.The flowing state of the liquid in helical channel becomes relatively complicated because of the curvature and torsion of helical channel,the centrifugal force and centripetal force cause the fluid to flow toward the wall and form the Dean vortex,and then flow field and velocity field will be changed.In addition to the use of helical channel instead of straight channel to improve the heat transfer efficiency of the passive heat transfer technology,the use of efficient heat exchange quality can further improve the performance of heat transfer equipment.For example,the nanofluid is prepared by adding nanoparticles and dispersing agent in the base liquid,because of higher thermal conductivity of nanoparticles and the Brown movement,it is widely used in the heat exchanger.The flow and heat transfer characteristics of the fluid in the helical channel have become a hot research topic in recent years,and they are of crucial guiding significance for practical applications.At present,the essential reason for the secondary flow is that the centrifugal force produced by the curvature and torsion of the helical channel can affect the fluid,however,with the secondary flow,the flow resistance will increase with the increase of heat transfer.On the other hand,the addition of nanoparticles in the base fluid not only has a significant improvement on the heat transfer coefficient,but also has higher flow resistance compared with the base fluid