中文摘要：

为了改进换热器设计方法及提高设备换热效率,通过建立恒定热流密度加热的圆管内层流脉动流动数学模型,对流量脉动条件下的流动与传热特性进行了数值分析.研究结果表明,脉动流动时速度与压降发生同周期的变化,但两者之间存在相位差,随着脉动频率增加,相位差逐步趋近于π/2;脉动速度的径向分布在一定频率范围内出现环状效应,频率越大速度脉动幅值越小,但环状效应越明显;温度脉动幅度随脉动频率、普朗特数增加而减小,随速度脉动幅度增加而增加.

英文摘要：

In order to improve the heat transfer equipment design and enhance the heat transfer efficiency,a mathematical model was established to analyze the flow and heat transfer characteristics of a pulsating laminar flow in a circular pipe,and the pipe was heated under a constant heat flux boundary condition.The results show that a phase lag exists between the flow velocity and pressure drop.With an increase in the pulsating frequency,the value of the phase lag tends to be π/2.In addition,the value of radial velocity fluctuation decreases with the increase of frequency,but the annular effect becomes more noticeable.Furthermore,the pulsating amplitude temperature decreases with the increase of frequency and Prandtl number,but increases with the increase of pulsating amplitude velocity.