Details

Autor(en) / Beteiligte

• Xing, Dianchuan
• Yan, Changqi
• Sun, Licheng
• Xu, Chao

Titel

Effects of rolling on characteristics of single-phase water flow in narrow rectangular ducts

Ist Teil von

• Nuclear engineering and design, 2012-06, Vol.247, p.221-229

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2012

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• ► Mass flow rate and friction pressure drop with different pressure head are compared. ► The effect of pressure head on flow fluctuation is considered theoretically. ► Time-mean and real-time friction pressure drop in different rolling motion are studied. ► Rolling motion influences the fluctuation of friction pressure drop in two aspects. ► New correlation for frictional coefficient in rolling motion is achieved. Experimental and theoretical studies of rolling effects on characteristics of single-phase water flow in narrow rectangular ducts are performed under ambient temperature and pressure. Two types of pressure head are supplied by elevate water tank and pump respectively. The results show that the frictional pressure drop under rolling condition fluctuates periodically, with its amplitude decaying as mean Reynolds number increase and the rolling amplitude decrease, while the amplitude is nearly invariable with rolling period. Rolling motion influences the fluctuation amplitude of frictional pressure drop in two aspects, on the one hand, rolling reduced periodical pulsing flow leads to the fluctuation of the frictional pressure drop, on the other hand, additional force acting on fluid near the wall due to the rolling motion makes local frictional resistance oscillate periodically. The mass flow rate oscillates periodically in rolling motion with the pressure head supplied by water tank, while its fluctuation is so weak that could be neglected for the case of the pressure head supplied by pump. An empirical correlation for the frictional coefficient under rolling condition is achieved, and the experimental data is well correlated. A mathematical model is also developed to study the effect of pressure head on mass flow rate fluctuation in rolling motion. The fluctuation amplitude of the mass flow rate decreases rapidly with a higher pressure head. Comparing with the vertical condition, rolling motion nearly has no effects on time-averaged frictional resistance for single-phase flow.