Analysis of experimental characteristics of multistage steam-jet electors of steam turbines

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• 作者：K. E. Aronson ; A. Yu. Ryabchikov ; Yu. M. Brodov ; D. V. Brezgin…
• 关键词：multistage steam ; jet ejector ; mixing chamber ; intercooler ; ejector characteristic
• 刊名：Thermal Engineering
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：64
• 期：2
• 页码：104-110
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Engineering Thermodynamics, Heat and Mass Transfer;
• 出版者：Pleiades Publishing
• ISSN：1555-6301
• 卷排序：64

文摘

A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the “sound tube” zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the “sound tube” define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70–80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector’s mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime.