汽轮机空心静叶热蒸汽喷射除湿方法的分析

Exergy Analysis for Moisture Removal Methods of Hot Steam Injection in Hollow Stationary Blade of Steam Turbine

在某汽轮机除湿级的空心静叶上设计了不同的热蒸汽喷射缝,应用两相均质混合模型和湿蒸汽平衡相变模型,对具有缝隙的叶栅流场进行了全三维定常的数值计算。引入参数的方法进行能量转化过程的经济性评估。结果表明:尾缘喷射热蒸汽时,同一喷射流量下,缝隙宽度越大,有效效率越高。同时,在较大缝隙宽度下,有一个最佳的喷射流量,此时的有效效率最高。压力面中部喷射热蒸汽时,在喷射流量比小于6%下,各方案的有效效率均比无热蒸汽喷射的原型要高。同一喷射流量下,顺主流喷射且缝隙宽度越大,其有效效率越高。

Hot steam injection slots with different configurations were designed at the hollow stationary blade for the special dehumidifier stage of a steam turbine. Employing two-phase homogeneous mixture model and equilibrium phase change model,flow fields of blade cascade with injection slot were solved by 3D steady numerical simulation. Exergy parameter was introduced as a measure to evaluate economic cost of energy conversion process. It indicates that for the injection at the trail edge,the bigger slot has a higher exergy effective efficiency in the case of equivalent injected quantity. Moreover,it has an optimal mass flow rate for a relatively large slot, which corresponds to the maximum exergy effective efficiency. For the injection slot at the middle of pressure surface, exergy effective efficiency with a less 6% mass flow ratio is higher than that of the original for no hot steam injection. In addition, the bigger slot along the mainstream direction has a higher exergy effective efficiency in the case of the equivalent injected quantity.