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蒸汽在安全壳内壁面上的冷凝是事故发生后安全壳内的气体向壳壁传热的主要方式,是影响钢制非能动安全壳压力响应的重要因素。针对事故后核电厂安全壳内的事故工况条件,在较宽的参数范围内开展了蒸汽冷凝传热过程的试验研究。试验压力为0.11~0.5 MPa(d),主流空气质量分数为29%~78%、壁面过冷度为26~60℃,混合气体平均流速0.4~1.9 m/s。试验结果表明:在0.9 m/s以下的低流速范围内,试验数据与经验关系式的计算结果符合较好;流速高于0.9 m/s时,流速成为影响含有不凝性气体的蒸汽凝结传热的主要因素之一;主流空气质量分数较低时,流速对含有不凝性气体蒸汽冷凝的传热系数的影响更加显著;对于伴有蒸汽冷凝的对流换热过程,由自然对流向混合对流转变的判据与单相对流换热过程不同。
The condensation of steam on the inner wall of the containment is the main mode of heat transfer from the containment to the shell wall after the accident. It is an important factor that affects the pressure response of the passive containment. Aiming at the conditions of accident conditions in the containment of nuclear power plant after the accident, the experimental study on the heat transfer process of steam condensation was carried out in a wide range of parameters. The experimental pressure was 0.11-0.5 MPa (d), the mainstream air mass fraction was 29% -78%, the wall undercooling was 26-60 ℃, and the average mixed gas flow rate was 0.4-1.9 m / s. The experimental results show that the experimental data are in good agreement with the empirical formula at a low flow rate of 0.9 m / s. When the flow rate is higher than 0.9 m / s, the flow rate becomes a factor affecting the condensation of steam containing non-condensable gases When the main air mass fraction is low, the influence of flow velocity on the heat transfer coefficient of steam condensing with non-condensable gas is more significant. For the convective heat transfer process with steam condensing, the convection from natural convection to mixed convection The criterion of transition is different from that of single-phase convection heat transfer.