|Journal||Journal of Mechanical Engineering – Problemy Mashynobuduvannia|
|Publisher||A. Pidhornyi Institute for Mechanical Engineering Problems
National Academy of Science of Ukraine
|ISSN||2709-2984 (Print), 2709-2992 (Online)|
|Issue||Vol. 25, no. 4, 2022 (December)|
|Cited by||J. of Mech. Eng., 2022, vol. 25, no. 4, pp. 25-31|
It has been established that in order to study thermo- and electrophysical phenomena in wet steam turbines, studies of the wet steam flow volume charge effect on its dielectric and thermophysical properties have recently been carried out at A. Pidhornyi Institute of Mechanical Engineering Problems of the National Academy of Sciences of Ukraine. According to their results, it was established that the most representative electrophysical parameter, which allows to evaluate changes in the thermophysical properties of steam, which occur under the action of its own volume charge, is its dielectric constant. It is assumed that the value of the dielectric constant of an electrified steam can be significantly different from the value for a neutral steam, and a mathematical assessment of its possible change is made. It has been confirmed that the influence of electrophysical phenomena caused by the wet steam flow electrification is significant, but is not taken into account in the existing physical and mathematical thermodynamic models of the steam expansion process. It is proved that in order to clarify the main thermodynamic parameters and calculated characteristics of the electrified wet steam flow, it is necessary to determine how its dielectric constant changes. On the basis of the analysis, the relevance of experimental determination of the dielectric constant of a wet steam flow with a volume charge in order to obtain the dependence of its change on the temperature and pressure of the flow, as well as the density of the volume charge, is substantiated. To perform the research, a gas dynamic laboratory plant, which allows to obtain a wet steam flow with a volume charge, was used. The internal space of the flow part of a real wet steam turbine has a significant size and allows the formation of a flow with a volume charge of a complex spatial configuration and structure. It is emphasized that in the flow part of the plant of a small volume, in contrast to the turbine flow part, significant technical difficulties arise when organizing the conditions for the occurrence of a wet steam flow with a volume charge. Taking this into account, at the first stage, it was decided to conduct a study of a steam flow with a volume charge flowing into the atmosphere in a laboratory room with a sufficient volume to form its spatial structure. To estimate the value of its dielectric constant, the inductive method (L-method) of determining dielectric properties, in which the substance under study is introduced into the inductive solenoid cell, was chosen. Experiments were conducted and, according to the obtained data, it is possible to make a preliminary assessment of the change in dielectric constant in the presence of a volume electric charge in the steam flow.
Keywords: wet steam turbines, thermophysical properties of the working fluid, dielectric constant, volume charge of steam flow.
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- Nechaiev, A. V., Tarelin, A. O., & Annopolska, I. Ye. (2022). Analysis of the influence of steam electrification on the working processes of a wet steam turbine. Journal of Mechanical Engineering – Problemy Mashynobuduvannia, vol. 25, no. 3, pp. 56–64. https://doi.org/10.15407/pmach2022.03.056.
- Mulev, Yu. V. (1984). Upravleniye vstroyennymi separatorami pryamotochnykh kotloagregatov SKD na osnove kontrolya vlazhnosti otseparirovannogo para [Control of built-in separators of once-through boilers SKD based on humidity control of separated steam]: Ph.D. dissertation. Belarusian Polytechnic Institute. Minsk, 212 p. (in Russian).
- Mulev, Yu. V., Belyayeva, O. V., Mulev, M. Yu., Saplitsa, V. V., & Zayats, T. A. (2011). Dielektricheskaya pronitsayemost kak odin iz osnovnykh parametrov kontrolya sostoyaniya rabochego tela [Dielectric constant as one of the main parameters for controlling the state of the working fluid]. Teploenergetika – Thermal Engineering, no. 7, pp. 36–40 (in Russian).
- Semikhina, L. P. (2005). Induktivnyy metod opredeleniya dielektricheskikh svoystv zhidkostey [Inductive method for determining the dielectric properties of liquids]. Nauchnoye priborostroyeniye – Scientific Instrumentation, vol. 15, no. 3, pp. 83–87 (in Russian).
- Semikhina, L. P. (2005). Opredeleniye magnitnykh i dielektricheskikh svoystv veshchestv s pomoshchyu induktivnykh L-yacheyek [Determination of magnetic and dielectric properties of substances using inductive L-cells]. Vestnik Tyumenskogo gosudarstvennogo universiteta – Bulletin of the Tyumen State University, no. 1, pp. 94–100 (in Russian).
- Tarelin, A. A. & Sklyarov, V. P. (2012). Parovyye turbiny: elektrofizicheskiye yavleniya i neravnovesnyye protsessy [Steam turbines: electrophysical phenomena and non-equilibrium processes]. St. Petersburg: Energotekh, 292 p. (in Russian).
- Tarelin, A. A., Surdu, N. V., & Nechayev, A. V. (2020). Vliyaniye elektrizatsii vlazhno-parovogo potoka na poverkhnostnuyu prochnost materialov lopatok turbiny [Influence of wet-steam flow electrization on the surface strength of turbine blade materials]. Teploenergetika – Thermal Engineering, vol. 67, no. 1, pp. 72‒81 (in Russian). https://doi.org/10.1134/S0040601520010073.
- Poplavko, Yu. M. (1980). Fizika dielektrikov [Physics of dielectrics]: Textbook for universities. Kiyv: Vishcha shkola, 400 p. (in Russian).
Received 20 October 2022
Published 30 December 2022