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为了降低转子由高温蠕变导致的永久弯曲变形速率,以俄制500 MW汽轮机对称进汽结构中压转子的冷却装置为研究对象,利用Fluent软件分析了不同冷却蒸汽流量对再热蒸汽流场的干扰程度以及对机组热效率的影响.在不同冷却蒸汽温度下,对转子前两级的表面温度分布以及转子的高温蠕变速率进行了计算.结果表明:当冷却蒸汽流量在20 t/h以下时,其对再热蒸汽流场的影响很小;冷却蒸汽的最小流量应该大于0.65 t/h,否则在第一级叶轮根部会发生蒸汽逆向流动;当冷却蒸汽流量在允许范围内变化时,流量对转子的冷却效果影响不大,影响转子温度场的主要因素是冷却蒸汽温度;当冷却蒸汽温度分别为470℃、480℃和490℃时,可以分别使转子的安全运行时间延长至19.0年、14.3年和11.0年.
In order to reduce the permanent bending deformation rate of the rotor caused by creep at high temperature, the cooling device of symmetrical inlet rotor of Russian-made 500 MW steam turbine is taken as the research object. The effects of different cooling steam flow rates on the reheat steam flow field The degree of disturbance and the influence on the thermal efficiency of the unit.The surface temperature distribution and the high temperature creep rate of the rotor at different cooling steam temperatures were calculated.The results show that when the cooling steam flow rate is under 20 t / h , Which has little effect on the reheat steam flow field; the minimum flow rate of the cooling steam should be greater than 0.65 t / h or steam reverse flow will occur at the root of the first stage impeller; when the cooling steam flow rate changes within the allowable range, the flow rate The main factor affecting the rotor temperature field is the temperature of the cooling steam; when the cooling steam temperature is 470 ℃, 480 ℃ and 490 ℃ respectively, the safe running time of the rotor can be prolonged respectively to 19.0 years, 14.3 years and 11.0 years.