Experimental Investigation on the Transcritical Dynamic Flow and Heat Transfer Characteristics of the Water Wall

被引：1
|
作者：
Liu J. [1 ]
Li H. [1 ]
Feng Y. [1 ]
Kong X. [1 ]
Lei X. [1 ]
机构：
[1] State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an
来源：
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | 2018年 / 52卷 / 11期
关键词：
Critical dryness; DNB heat transfer deterioration; Near-critical pressure region; Transcritical dynamic characteristics; Wall temperature rise;
D O I：
10.7652/xjtuxb201811001
中图分类号：
学科分类号：
摘要：
Aiming at the special flow and heat transfer characteristics in the transcritical variable-pressure operating process of the water-wall in the supercritical once through boiler, experiments were conducted to investigate the transcritical dynamic flow and heat transfer characteristics in a vertical upward heated pipe under 19-25 MPa of pressure, 300-800 kg/(m 2 •s) of mass velocity and 60-250 kW/m 2 of heat flux on the pipe outerwall. The experimental results showed that a wall temperature rise always occurs in the transcritical dynamic process of the heated pipe, which is caused by the DNB heat transfer deterioration in the near-critical pressure region. With the increase of the fluid pressure, the nearer is the fluid pressure close to the critical point, the lower is the fluid enthalpy needed to induce the occurrence of DNB, and the higher the deterioration degree will be. Moreover, DNB heat transfer deterioration even occurs when the working fluid is still in a subcooled state under most of our experimental cases, and this seriously threats the safe running of the water-wall system. Based on the parameter range of our experiments and the analysis on the operation of water-wall, DNB heat transfer deterioration is likely to occur in the transcritical dynamic process when the local fluid enthalpy in the heated pipe is higher than 1 600 kJ/kg. The experimental results in this research can provide a guidance for the design and adjustment of the operation conditions in the water-wall of the supercritical once through boiler. © 2018, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.
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页码：1 / 8and126
页数：8125
相关论文
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