CIESC Journal ›› 2019, Vol. 70 ›› Issue (7): 2488-2495.DOI: 10.11949/j.issn.0438-1157.20181491

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Oscillatory heat transfer characteristics of supercritical water in parallel channels

Ziyu LIANG(),Li WAN,Juan LI,Xihong ZHOU,Dong YANG()   

  1. State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China
  • Received:2018-12-19 Revised:2019-04-08 Online:2019-07-05 Published:2019-07-05
  • Contact: Dong YANG

并联双通道内超临界水的脉动传热特性

梁梓宇(),万李,李娟,周熙宏,杨冬()   

  1. 西安交通大学动力工程多相流国家重点实验室,陕西 西安 710049
  • 通讯作者: 杨冬
  • 作者简介:梁梓宇(1993—),男,硕士研究生,<email>1950914370@qq.com</email>
  • 基金资助:
    国家重点研发计划项目(2016YFB0600201)

Abstract:

The oscillatory heat transfer characteristics of supercritical water in vertical upward parallel channels were experimentally investigated under the condition of pressure from 26—30 MPa, time-averaged mass flow rate of 420 kg·m-2·s-1 and heat flux from 0—130 kW·m-2. According to the experimental results, the effects of mass flow rate oscillation on wall temperature, oscillatory amplitude ratio ( Af ) and oscillatory frequency number ( Wo ) on time-averaged Nusselt number were analyzed, and the time-averaged Nu of oscillatory flow was compared with the supercritical heat transfer correlation equations. The results show that the wall temperature fluctuates with mass flow rate oscillation at the same oscillatory period and opposite phase, and the larger amplitude of mass flow rate oscillation leads to the stronger fluctuation of wall temperature. At the occurrence of low frequency oscillation, the time-averaged Nu decreases with the increase of oscillatory amplitude ratio, and decreases firstly with the increase of oscillatory frequency number and then remains constant. At the occurrence of high frequency oscillation, the time-averaged Nu increases slowly with the increase of oscillatory amplitude ratio, and decreases with the increase of oscillatory frequency number. The values of Nu predicted by correlations is generally higher than that of experiments.

Key words: supercritical water, heat transfer, riser, oscillatory amplitude ratio, oscillatory frequency number, oscillation of wall temperature

摘要:

在压力26~30 MPa,时均质量流速420 kg·m-2·s-1、热通量0~130 kW·m-2工况范围内,对垂直上升并联双通道内超临界水的脉动传热特性进行了实验研究。根据实验数据分析了流量脉动对壁温的影响,脉动振幅率(Af)和脉动频率数(Wo)对时均Nusselt数的影响,并将脉动时均Nu与超临界传热关联式进行了比较。结果表明:壁温随流量脉动而波动,脉动周期相同,相位相反,流量脉动振幅越大,壁温波动也越大;低频脉动时均Nu随脉动振幅率的增大逐渐减小,随脉动频率数的增大先减小后基本不变;高频脉动时均Nu随脉动振幅率的增大而缓慢增大,随脉动频率数的增大而减小;关联式预测的Nu较实验值普遍偏高。

关键词: 超临界水, 传热, 上升管, 脉动振幅率, 脉动频率数, 壁温脉动

CLC Number: