Recommendations on selecting the closing relations for calculating friction pressure drop in the loops of nuclear power stations equipped with VVER reactors

2013 ◽  
Vol 60 (5) ◽  
pp. 331-337 ◽  
Author(s):  
V. M. Alipchenkov ◽  
V. V. Belikov ◽  
A. V. Davydov ◽  
D. A. Emel’yanov ◽  
N. A. Mosunova
Keyword(s):  
Pressure Drop ◽  
Nuclear Power ◽  
Power Stations ◽  
Friction Pressure ◽  
Friction Pressure Drop ◽  
Closing Relations

Two-Phase Void Fraction and Pressure Drop in Horizontal Crossflow Across a Tube Bundle

1998 ◽  
Vol 120 (1) ◽  
pp. 140-145 ◽  
Author(s):  
G. P. Xu ◽  
K. W. Tou ◽  
C. P. Tso
Keyword(s):  
Pressure Drop ◽  
Void Fraction ◽  
Mass Velocity ◽  
Flow Model ◽  
Tube Bundle ◽  
Diameter Ratio ◽  
Two Phase ◽  
Friction Pressure ◽  
Oil Flow ◽  
Friction Pressure Drop

Void fraction and friction pressure drop measurements were made for an adiabatic, horizontal two-phase flow of air-water, air-oil across a horizontal in-line, 5 × 20 tube bundle with pitch-to-diameter ratio, P/D, of 1.28. For both air-water and air-oil flow, the experimental results showed that the average void fraction were less than the values predicted by a homogenous flow model, but were well correlated with the Martinelli parameter Xtt and liquid-only Froude number FrLO. The two-phase friction multiplier data exhibited an effect of flow pattern and mass velocity, and they could be well-correlated with the Martinelli parameter.

Condensation Heat Transfer and Pressure Drop of R134A in Horizontal Micro-Scale Enhanced Tube

2020 ◽  
Author(s):  
Zongbao Gu ◽  
Xiang Ma ◽  
Yan He ◽  
Lianxiang Ma ◽  
David J. Kukulka ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Evaluation Criteria ◽  
Smooth Tube ◽  
Vapor Quality ◽  
Micro Scale ◽  
Friction Pressure ◽  
Friction Pressure Drop ◽  
Enhanced Surface

Abstract This study was performed to investigate the heat transfer and pressure drop of R134A during condensation inside a stainless steel micro-scale enhanced surface tube (EHT tube) and smooth tube. The tests were conducted at a saturation temperature of 45°C, over the mass fluxes range of 100 to 200 kg/m2s, the heat fluxes of 14–25 kW/m2, an inlet vapor quality of 0.8 and outlet vapor quality of 0.2. The heat length and inner diameter of the tested tube were 2 m and 11.5 mm. The micro-scale enhanced surface tube has complex surface structures composed of dimples and petal arrays background patterns. It can be observed the condensation heat transfer coefficients of the EHT tube is about 1.6–1.7 times higher than that of a stainless steel smooth tube. Enhancement of the EHT tube was achieved due to disruption of the boundary layer, secondary fluid generation, increasing fluid turbulence and heat transfer area. In addition, considering the friction pressure drop, the EHT tube produces the larger friction pressure drop, which is 1.05–1.20 times as compared to the smooth tube. Finally, the performance factors were performed to evaluate the enhancement effect of the EHT tube based on heat transfer coefficient-pressure drop evaluation criteria value (η1) and heat transfer coefficient-area evaluation criteria value (η2).

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