Abstract

Energy losses caused by steam humidity are one of the main components of losses in the steps of nuclear power plants’ wet-steam turbines. The presence of moisture droplets in the flow part of the turbines also poses a serious danger due to erosion wear of their blades. Various separation systems remove part of the erosion-hazardous moisture. However, along with moisture, a certain amount of steam is removed from the flow part of the turbine, which will not take part in performing beneficial work in subsequent stages of this turbine. Other losses are steam leaks through seals, the largest of which occur in seals located above the turbine blades. On the basis of the rectangular-mesh seals developed and studied earlier, the design of a special peripheral seal for NPP turbines was developed at NRU MPEI. The new seal is capable of simultaneously performing two functions: to reduce over-leakage leaks and to ensure the separation of moisture from the flowing part. The results of the studies showed that the presence of special channels in the seal for removing drip moisture hardly worsen the flow characteristics of the new seal. This paper presents the results of experimental studies into the separation ability of new peripheral seals. As a two-phase medium, specially prepared moist air was used. To do this, a plant for the preparation of water and the generation of the droplet phase was designed and manufactured. During the experiments, the ability of the seal structure to remove moisture was investigated. The use of humidified air made it possible to accurately determine the amount of droplet moisture supplied to the seal and separated through it and the separation coefficient of the seal. Studies have shown that the amount of moisture separated through the seal depends on the pressure drop across it, the rotor speed, and the initial degree of humidity of the compressed air supplied to the seal. It is shown that the use of a new seal in the studied range of initial degrees of humidity allows the separation of up to 45% of the moisture passing through the peripheral gap above the working blades. In general, the results of the experiments showed that the use of a rectangular-cell seal from NRU MPEI as a peripheral seal in turbines of nuclear power plants is advisable to remove moisture from the gap above the working blade and to reduce peripheral steam leaks.

中文翻译：

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新型NRU MPEI外围密封件的分离能力研究

摘要

由蒸汽湿度引起的能量损失是核电厂湿蒸汽涡轮机步骤中损失的主要组成部分之一。由于涡轮机叶片的磨损，在涡轮机的流动部分中还存在水滴，这也构成了严重的危险。各种分离系统可以去除部分腐蚀有害的水分。然而，连同水分一起，一定量的蒸汽从涡轮机的流动部分去除，这将不参与在该涡轮机的后续阶段中进行有益的工作。其他损失是通过密封件泄漏的蒸汽，其中最大的泄漏发生在位于涡轮机叶片上方的密封件中。在较早开发和研究的矩形网状密封件的基础上，NRU MPEI开发了一种用于NPP涡轮机的特殊外围密封件的设计。新的密封件能够同时执行两项功能：减少过度泄漏，并确保水分与流动部件分离。研究结果表明，密封件中用于除去滴水的特殊通道几乎不会恶化新密封件的流动特性。本文介绍了对新型外围密封件分离能力的实验研究结果。作为两相介质，使用了专门准备的潮湿空气。为此，设计并制造了用于制备水和产生液滴相的设备。在实验过程中，研究了密封结构去除水分的能力。通过使用加湿空气，可以准确地确定供给至密封件并通过密封件分离的液滴水分的量以及密封件的分离系数。研究表明，通过密封件分离出的水分量取决于密封件两端的压降，转子转速以及提供给密封件的压缩空气的初始湿度。结果表明，在所研究的初始湿度范围内使用新的密封件，可使分离出最多45％的水分通过工作刀片上方的外围间隙。一般来说，