ASYMMETRY INVESTIGATION ON SINGLE PHASE FLOW IN INVERTED U-TUBES OF STEAM GENERATOR UNDER THE CONDITION OF NATURAL CIRCULATION
In order to study the reverse flow characteristics in U-tubes of steam generator in the natural circulation case, the code RELAP5/MOD3.3 is used to model and calculate single-phase water flow for PWR under some typical operating conditions in the natural circulation case. The U-tubes of steam generator are classified according to their length and then are divided into different nodes and flow lines. The calculated results show that reverse flow exists in some inverted U-tubes of the steam generator, the natural circulation capacity of the primary coolant circuit system declines and the calculated net mass flux of the natural circulation accords with the experimental data. The traditional lumped parameter method can not simulate the reverse flow characteristics in inverted U-tubes and its result is much greater than the experimental data ．When the steam generator outlet pressure is higher than inlet pressure, and gravitational pressure drop is lower than the total of frictional pressure drop and area change pressure drop, the reverse flow will occur. As to the nuclear power plant described in this paper, the mass flux of the shorter U-tubes drops more quickly and at last reverse flow will occur. The temperature distribution is uniform in inverted U-tubes, and it is almost identical with that of SG in secondary side. The occurrence of reverse flow can be judged by that whether the steam generator inlet temperature is lower than reactor outlet temperature obviously. It is indicated that reverse flow occurred in the U-tubes of the steam generator reduces the mass flux in the natural circulation system.
WANG Chuan YU Lei
Department of Nuclear Science and Engineering,Naval Univ.of Engineering, Wuhan 430033, China Department of Nuclear Science and Engineering Naval Univ.of Engineering, Wuhan 430033, China
国际会议
18th International Conference on Nuclear Engineering(第18届国际核能工程大会 ICONE 18)
西安
英文
1-7
2010-05-17（万方平台首次上网日期，不代表论文的发表时间）