CFD-calculation of losses in the inlet pipe of a turbo-expander centrifugal compressor

Technological cycles of complex preparation and transportation of gas in the gas and oil industry are impossible without the use of compressors for various purposes and types. In the gas industry, the installed power of centrifugal compressors is about 55 million kW. The role of turbo-expander units...

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Bibliographic Details
Main Authors: Galerkin, Yu. B., Rekstin, A. F., Semenovsky, V. B., Maksimenko, I. A.
Format: Conference Proceeding
Language:English
Subjects:
Associated natural gas
Centrifugal compressors
Dynamic characteristics
Gas dynamics
Inlet pipes
Modelling
Software
Turboexpanders
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Summary:Technological cycles of complex preparation and transportation of gas in the gas and oil industry are impossible without the use of compressors for various purposes and types. In the gas industry, the installed power of centrifugal compressors is about 55 million kW. The role of turbo-expander units is quantitatively secondary (about 1 million kW of installed power), but without turbo-expander it is impossible to transport and process natural and associated petroleum gas. The necessity to ensure high efficiency for turbo-expander compressors in the whole variety (from 2 to 18) of possible modes of operation of the unit creates objective difficulties in the implementation of gas-dynamic projects of such machines. Since the mid-2000s, the main domestic manufacturer of turbo-expander units has been JSC «Turboholod». For the design of centrifugal compressors was attracted St. Petersburg Polytechnic University, where the Universal Modeling Method was created for this target. Single set of calculation methods and its implementation in the form of interactive computer programs allows to perform optimal design and predict the operation of the compressor at modes that change significantly during operation of the gas field. At the beginning of 2022, 24 projects of centrifugal compressors for more than 125 turbo-expanders were completed by using the Universal Modeling Method. The unit power of the compressor is up to 6500 kW, the final pressure is up to 12 MPa, the total power is more than 400 thousand kilowatts. The experience of using by the authors of commercial calculation complexes that implement the methods of computational gas dynamics (CFD) has shown that the correct calculation of the gas-dynamic characteristics of a centrifugal compressor still cannot be guaranteed. At the same time, the CFD calculation provides correct information of the flow in the stator elements of the flow path. The specificity of the discussed turbo-expander lies in the wide of use of unified elements in the design of the turbo-expander unit casing and piping. With a significant change in volumetric flow, losses in the inlet path of a unified body can reach unacceptably big values. This requires a change in the flow sections of the inlet path. CFD calculation and subsequent analysis of the flow in the inlet tract, consisting of a supply pipe, revealed problem areas in the inlet pipe. This analysis made the possibility to assess the losses of efficiency and set the directions for impro
ISSN:0094-243X
1551-7616
DOI:10.1063/5.0140852