Wave and flow loads on inclined pipe at different immersion depths

An experimental investigation of opposing mixed convection in an inclined pipe has been conducted. Dye injection reveals the existence of flow reversal regions. There is an optimal tilt angle that yields maximum flow reversal length. Flow reversals are seen to cause early transition to turbulence. Temperature profiles are measured across the tube cross section near the entrance to the heated section, and show the effect of tube inclination. Temperature measurements exhibit periodic behavior in the flow reversal region under some conditions, generally characterized by low tilt angle and moderate to high Reynolds and Grashof numbers. Flow visualization indicates that this periodic behavior is due to the intermittent breakdown of the flow reversal region.

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Research of friction characteristics on the hydraulic transportation in inclined slurry-pipe

E3S Web of Conferences ◽

10.1051/e3sconf/202019801030 ◽

2020 ◽

Vol 198 ◽

pp. 01030

Author(s):

Wang Tieli

Keyword(s):

Experimental Data ◽

Momentum Transfer ◽

Interaction Mechanism ◽

Hydraulic Gradient ◽

Solid Particles ◽

Friction Loss ◽

Acceleration Time ◽

New Model ◽

Inclined Pipe ◽

Inclined Pipes

By analyzing the momentum transfer and velocity both of solid particles and water over the acceleration time of solid particles, as well as interaction mechanism between water and solid particals, a new model is proposed to predict friction loss for setting slurry flow in inclined pipe. The hydraulic gradient formula for inclined pipes summarized by the author is confirmed by a large amount of experimental data. The results show that the deviation between the theoretical value of the model proposed by the author and the measured value is not more than 13.33%, which is the smallest among all reports.

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Heat transfer enhancement during condensation of water steam on inclined pipe

Journal of Physics Conference Series ◽

10.1088/1742-6596/2039/1/012031 ◽

2021 ◽

Vol 2039 (1) ◽

pp. 012031

Author(s):

S Z Sapozhnikov ◽

V Yu Mityakov ◽

A V Mityakov ◽

A Yu Babich ◽

E R Zainullina

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Heat Transfer Enhancement ◽

Unit Area ◽

Experimental Results ◽

Transfer Enhancement ◽

Water Steam ◽

Saturated Water ◽

Informative Content ◽

Inclined Pipe

Abstract This paper presents experimental study of heat transfer during film condensation of saturated water steam on the outer surface of the inclined pipe by gradient heatmetry. Heat flux per unit area was measured by gradient heat flux sensors made of a single-crystal bismuth. The experimental results are presented in the graphs of heat flux per unit area dependence on time and azimuthal angle. The highest average heat transfer coefficient during condensation of α = 6.94 kW/(m2 • K) was observed when the pipe was inclined at the angle of ψ = 20 °. This value exceeds one obtained on a vertical pipe by 14.9 %. Heat transfer enhancement during condensation of saturated water steam on inclined pipe is associated with changes in condensate film flow. Another part of experiments was made by simultaneously using of gradient heatmetry and condensate flow visualization. Experimental results confirmed the applicability and high informative content of proposed comprehensive method. Comprehensive study of heat transfer during condensation confirmed that heat flux per unit area pulsations may be explained by the formation of individual drops, their coalescence, and drainage from the sensor surface.

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Effects of Diameters on Countercurrent Flow Limitation at a Square Top End in Vertical Pipes

Science and Technology of Nuclear Installations ◽

10.1155/2018/1426718 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Michio Murase ◽

Koji Nishida ◽

Toshihide Torige ◽

Toshiya Takaki ◽

Raito Goda ◽

...

Keyword(s):

Water Level ◽

Flow Rate ◽

Liquid Flow ◽

Liquid Flow Rate ◽

Strong Relationship ◽

Countercurrent Flow ◽

Flow Limitation ◽

Vertical Pipe ◽

Surge Line ◽

Inclined Pipe

The falling liquid flow rate under flooding conditions is limited at a square top end of a vertical pipe in the pressurizer surge line with the diameter of about 300 mm that consists of a vertical pipe, a vertical elbow, and a slightly inclined pipe with elbows. In this study, therefore, we evaluated effects of diameters on countercurrent flow limitation (CCFL) at the square top end in vertical pipes by using existing air-water data in the diameter range of D = 19-250 mm. As a result, we found that there was a strong relationship between the constant CK and the slope m in the Wallis-type correlation where the Kutateladze parameters were used for the dimensionless gas and liquid velocities. The constant CK and the slope m increased when the water level is increased in the upper tank h. CCFL at the square top end of the vertical pipes could be expressed by the Kutateladze parameters with CK = 1.53±0.11 and m = 0.97 for D ≥ 30 mm. The CK values were smaller for D = 19-25 mm than those for D ≥ 30 mm.

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