Heat-Transfer Studies of Water Flow in Thin Rectangular Channels: Part II – Boiling Burnout Heat Flux for Low-Pressure Water in Natural Circulation

1964 ◽  
Vol 18 (1) ◽  
pp. 80-89 ◽  
Author(s):  
W. R. Gambill ◽  
R. D. Bundy
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Water Flow ◽  
Natural Circulation ◽  
Low Pressure ◽  
Rectangular Channels ◽  
Pressure Water

Downflow Post-Critical Heat Flux Heat Transfer to Low Pressure Water

1982 ◽  
Vol 56 (1) ◽  
pp. 134-140
Author(s):  
Paul Robershotte ◽  
Peter Griffith
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Low Pressure ◽  
Pressure Water

Experimental study on saturated boiling of two phase natural circulation under low pressure in narrow rectangular channels

Kerntechnik ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. 631-636
Author(s):  
Li Zi-chao ◽  
Qi Shi ◽  
Zhou Tao ◽  
Li Bing ◽  
Muhammad Ali Shahzad ◽  
...  
Keyword(s):  
Experimental Study ◽  
Natural Circulation ◽  
Low Pressure ◽  
Two Phase ◽  
Rectangular Channels ◽  
Saturated Boiling

Experimental study on Ledinegg flow instability of two-phase natural circulation in narrow rectangular channels at low pressure

2017 ◽  
Vol 98 ◽  
pp. 321-328 ◽  
Author(s):  
Shi Qi ◽  
Tao Zhou ◽  
Bing Li ◽  
Muhammad Ali Shahzad ◽  
Yaxiong Zou ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flow Instability ◽  
Natural Circulation ◽  
Low Pressure ◽  
Two Phase ◽  
Rectangular Channels

An Experiment of Natural Circulation Flow and Heat Transfer With Supercritical Water in Parallel Channels

2016 ◽  
Vol 2 (3) ◽  
Author(s):  
Yuzhou Chen ◽  
Chunsheng Yang ◽  
Minfu Zhao ◽  
Keming Bi ◽  
Kaiwen Du
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Rate ◽  
Supercritical Water ◽  
Dynamic Instability ◽  
Flow Instability ◽  
Natural Circulation ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Parallel Channels

An experiment of natural circulation of supercritical water in parallel channels was performed in bare tubes of inner diameter 7.98 mm and heated length 1.3 m, covering the ranges of pressure of 24.7–25.5 MPa, mass flux of 400–1000  kg/m2 s, and heat flux of up to 1.83  MW/m2. When the heat flux reached 1.12  MW/m2, the outlet water temperature jumped from 325°C to 360°C, associated with a decrease in the flow rate and an initiation of dynamic instability. When the heat flux exceeded 1.39  MW/m2, the flow instability was stronger, and the flow rate increased in one channel and decreased in another one. Until the heat flux reached 1.61  MW/m2, the outlet water temperatures of two channels reached the pseudocritical point, and the flow rates of two channels tended to close each other. The experiment with a single heated channel was also performed for comparison. The measurements on the heat-transfer coefficients (HTCs) were compared to the calculations by the Bishop et al., Jackson’s, and Mokry et al. correlations, showing different agreements within various conditions.

Local Single-Phase Heat Transfer Research of Natural Circulation in Narrow Rectangular Channel

2017 ◽  
Author(s):  
Zhiqiang Zhu ◽  
Xiaxin Cao ◽  
Changqi Yan ◽  
Chunping Tian
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Inclination Angle ◽  
Local Nusselt Number ◽  
Single Phase ◽  
Natural Circulation ◽  
Rectangular Channel ◽  
Inlet Temperature

In order to explore and analyze the heat transfer characteristics in narrow rectangular channel, experiments on local single-phase heat transfer of natural circulation in a one-side heating narrow rectangular channel have been conducted under vertical and inclined condition. The thermotechnical parameters such as inlet temperature, heat flux and inclination angle varies during the experiments. The width of the flow channel is 40 mm and the narrow gap is 2 mm. It is heated from one side with a homogeneous and constant heat flux and the working medium is deionized water. Based on the experimental results, under vertical condition, the driving force in the loop goes up and the Reynolds number also increases when the inlet temperature is elevated, which causes an increase in local Nusselt number. When the heat flux rises, the local Nusselt number increases and the heat transfer temperature difference increases. The local Nusselts number is influenced by entrance effect and the entrance region length is computed for laminar and turbulent flow. Under inclined condition, with the inclination angle from −30° to 30°, it is found that when the inclination angle is positive, the local Nusselt number in fully developed region is larger than that under vertical condition and increases with the angle value, even though the Reynolds number decreases by the effect of incline. This phenomenon is explained by giving an analysis of the natural convection, which is characterized by the normal Grashof number, in the direction perpendicular to the heating plat. Moreover, the variation of heat transfer is also interpreted on the basis of field coordination principle. However, when the inclination angle is negative, the heat transfer shows no obvious difference between vertical condition and inclined condition.

CFD Analysis on Wall Boiling Model During Subcooled Boiling in Vertical Narrow Rectangular Channel

2018 ◽  
Author(s):  
Tingting Ren ◽  
Changqi Yan ◽  
Meiyue Yan ◽  
Shengzhi Yu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fluid Model ◽  
Rectangular Channel ◽  
Subcooled Boiling ◽  
Site Density ◽  
Rectangular Channels ◽  
Two Fluid Model ◽  
Nucleate Site ◽  
Two Fluid

Two-fluid model is a common method to simulate the subcooled flow boiling heat transfer, in which the wall boiling model is mainly used for the partition of wall heat flux and the mass transfer between two phases on the wall. The model determines the amount of vapor phase and predicts the cross-sectional void fraction in the channel, nucleate site density and bubble departure diameter play an important role in the accurate prediction of wall boiling model. Eulerian two-fluid model coupled with Rensselaer Polytechnic Institute (RPI) wall boiling model is employed to simulate the heat transfer characteristics and boiling phenomena in vertical narrow rectangular channels by using FLUENT code. Based on the experimental data of subcooled boiling in vertical narrow rectangular channel, different combinations of nucleate site density and bubble departure diameter correlations are used to calculate under different conditions of heat flux and inlet subcooling. Comparing the calculated heat transfer coefficients along the vertical height with experimental results, it can be found that these two parameters have a significant effect on the subcooled boiling heat transfer in narrow rectangular channels. Different parameter combinations lead to differences in wall heat flux distribution, different heat flux and inlet subcooling also have different effects on these models, which eventually lead to different evaporative heat flux, thus affecting the prediction of void fraction.

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