Investigation into the effects of surface condensation in steam-driven twin screw expanders / trans. from Engl. M. A. Fedorova
During the operation of twin screw expanders with slightly superheated vapours or even two-phase fluids, surface condensation on machine parts occurs during the filling period and the expansion phase when the working fluid is in contact with cooler inner surfaces. This heat exchange from the worki...
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| Format: | Article |
| Language: | English |
| Published: |
Omsk State Technical University, Federal State Budgetary Educational Institution of Higher Education
2021-03-01
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| Series: | Омский научный вестник: Серия "Авиационно-ракетное и энергетическое машиностроение" |
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| Online Access: | https://www.omgtu.ru/general_information/media_omgtu/journal_of_omsk_research_journal/files/arhiv/2021/%D0%A2.%205,%20%E2%84%96%201%20(%D0%90%D0%A0%D0%B8%D0%AD%D0%9C)/44-52%20%D0%93%D1%80%D0%B8%D0%B1%20%D0%9C.,%20%D0%91%D1%80%D1%8E%D0%BC%D0%BC%D0%B5%D1%80%20%D0%90..pdf |
| Summary: | During the operation of twin screw expanders with slightly superheated vapours or even two-phase
fluids, surface condensation on machine parts occurs during the filling period and the expansion phase
when the working fluid is in contact with cooler inner surfaces. This heat exchange from the working
fluid to adjacent machine parts effects the working cycle and the efficiency of these machines. Short
time scales and the periodicity of the process indicate the condensation process is best described by
models for dropwise condensation. In this paper the effects of surface condensation on the operation
of twin screw expanders are initially discussed in a simulation-based investigation. Chamber model
simulation coupled with a thermal analysis is used for the thermodynamic simulation, whereby heat
transfer coefficients are systematically varied. It is found that during the inlet phase condensate emerges
on the inner surfaces of the machine being substantially cooler than the working fluid. This results in a
higher mass being trapped within the working chamber and, thus, an increasing mass flow rate of the
machine. An increase in power output is, however, not observed. The results obtained from chamber
model simulations are finally compared against experimental data of a screw expander prototype |
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| ISSN: | 2588-0373 2587-764X |