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Development and testing of a method of identifying mathematical models of steam turbine condensers by a small sample of experimental data

G.V. Leduhovsky

Vestnik IGEU, 2017 issue 1, pp. 5—10

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Abstract in English: 

Background: Operation of steam turbines requires calculating condenser energy characteristics including the dependences of exhaust steam pressure and subcooling of cooling water to the saturation temperature in the condenser vapor space on the condenser vapor load, cooling water inlet temperature and flow rate. The energy characteristics can be obtained by thermal tests which, however, may be accompanied by operational difficulties. Therefore, energy characteristics are normally obtained by using the results of condenser confirmatory thermal calculations. A number of proven techniques of condenser confirmatory thermal calculations have been described in literature but all the techniques have to be adjusted to the real technical conditions of a certain facility in order to achieve acceptable accuracy of results in solving practical problems. Therefore, an urgent problem to be solved in the power industry is to develop a technique of identifying mathematical models of steam turbine condensers by a small sample of experimental data obtained by rapid tests or operational data observations.

Materials and methods: The study employed methods of steam turbine condenser confirmatory thermal calculations, methods of experimental studies, mathematical statistics and probability theory.

Results: A technique has been developed for identifying mathematical models of turbine condensers by a small sample of experimental data. The technique specifies the selected basic verification technique of thermal confirmatory calculation by introducing a correction factor to the heat transfer coefficient. The correction factor is determined by the condition of the minimum mismatch between the calculated and experimental values of condenser efficiency indicators for the conditions of each experiment, constituting the sample of experimental data, with the subsequent collection of empirical data of the models as a statistical dependence of the correction factor on the regime or structural conditions.

Conclusions: The proposed technique can be used to develop a condenser mathematical model by a small sample of experimental data. It allows calculating the energy characteristics of the condensing unit in specific operating conditions of a certain steam turbine with the accuracy acceptable for solving practical problems.

Key words: steam turbine condensing unit, thermal confirmatory calculation technique, steam turbine condenser energy characteristics, mathematical model, mathematical model identification, mathematical model adequacy, regression analysis, multiple linear regression, software system, steam turbine thermal tests.

References in English: 

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Ключевые слова на русском языке: 
конденсационная установка паровой турбины, методика поверочного теплового расчета, энергетические характеристики конденсатора паровой турбины, математическая модель, идентификация математической модели, адекватность математической модели, регрессионный анализ, множественная линейная регрессия, программный комплекс, тепловые испытания паровой турбины
Ключевые слова на английском языке: 
steam turbine condensing unit, thermal confirmatory calculation technique, steam turbine condenser energy characteristics, mathematical model, mathematical model identification, mathematical model adequacy, regression analysis, multiple linear regression, software system, steam turbine thermal tests
The DOI index: 
10.17588/2072-2672.2017.1.005-010
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