Cfd simulation of a two stage twin screw compressor including leakage flows and comparison with experimental data

Andres, Rainer; Hesse, Jan; Hetze, Farai; Low, D. M.

doi:10.1088/1757-899x/425/1/012018

Cited by 8 publications

(7 citation statements)

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“…The results showed that the volumetric and indicated efficiency of the second stage is more sensitive to the operating condition than that of the first stage. Andres et al [17] carried out a transient simulation on a gear-driven oil-free screw compressor by CFD, and the calculated flow rate and power consumption had a good match with the experimental measurements. Cipollone et al [18] developed a comprehensive mathematical model to study the performance of a dual-stage sliding vane rotary compressor, which applied pressure swirled oil atomizers in each stage and an air to air intercooler between two stages.…”

Section: Introductionmentioning

confidence: 92%

Experimental research on influence of interstage oil injection in a dual-motor-driven two-stage screw air compressor

Liao

Wang

Yuan

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Energy saving for compressed air production is of great importance all over the world due to its great energy cost and the indispensable utility of compressed air in the industrial sector. In recent years, oil-injected two-stage screw air compressors, especially driven by dual motors, are becoming a promising alternative to other compression equipment for their extraordinary efficiency and high reliability in a wide range of applications. However, two-stage screw air compressors have a different and complicated oil injection system compared with single-stage compressors. And an appropriate setting of oil injection parameters might result in a considerable performance improvement of the compressor. In this paper, a dual-motor-driven two-stage oil-injected screw compressor was tested under the actual service conditions and control modes experimentally. The effect of interstage oil injection on the compressor performance was studied in detail by varying the interstage oil injection flow rate and rotating speed. The performance parameters such as specific power, volumetric efficiency and adiabatic efficiency were calculated from the measured data. The results indicate that an excess amount of oil exists in the second stage compressor and reducing the oil moderately could decrease the power consumption of the two-stage air compressor unit.

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Section: Introductionmentioning

confidence: 92%

Experimental research on influence of interstage oil injection in a dual-motor-driven two-stage screw air compressor

Liao

Wang

Yuan

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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“…The 3D grid is created with improved resolution when all 2D grids have been finished. In general, the criteria for evaluating the quality of calculation grids for volumetric machines with positive displacement [32] are based on the following:  the grid must accurately represent the fluid domain  the internal angle must be greater than 18° and the element distribution must be uniform  small changes in the position of the nodes for two consecutive angles  the number of grids per rotation must be adequate, preferably from degree to degree Since all 3D grids have the same grid topology and number of nodes, the CFD solver can handle deformed grids without interpolation by applying just conservation rules. The number of elements and their types for each subdomain are shown in Table I.…”

Section: Grid Generationmentioning

confidence: 99%

Computational Fluid Dynamics Evaluation of an Oil-flooded Screw Compressor

Malael,

Petrescu

2023

Eng. Technol. Appl. Sci. Res.

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The cost of energy is directly influenced by geopolitical, economic, and environmental factors. There is an international trend towards renewable resources, although the implementation pace and legislation in force have issues. Complete abolishment of fossil fuels is practically impossible. Evolution is only possible with the use of these fuels but with modern, efficient equipment to reduce the pollution resulting from the process of extracting, processing, and using fossil fuels. In this paper, a screw compressor with oil injection, used in oil extraction stations, is analyzed numerically. This analysis is useful in the process of modernizing and improving the efficiency of this type of compressor, which is capable of operating in extreme working regimes, highly contaminated with impurities. The numerical analysis presented certain challenges related to biphasic flow in extremely small spaces at high compression ratios. The results include the absolute pressure variation and the flow rate variation. Regarding future research, test series will be carried out to validate the numerical results on the test bench with a 1:1 scale prototype.

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“…Here, the rotational periodicity of the rotor pair is considered, so that the set of grids is only generated for one pitch angle, i. e. 90° (360° divided by the number of male rotor lobes). This meshing approach and the CFD models were validated for a 2-stage screw compressor [5], a screw refrigeration compressor [6], and a screw expander [7], and in several confidential projects for clients.…”

Section: Rotor Chamber Modelingmentioning

confidence: 99%

Investigation of radial gap size change under load and the impact on performance for a twin screw compressor using numerical simulation

Andres

Hesse

Spille

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM) are common and validated tools in research and industry for solving fluid flow or performing structural analysis respectively. Despite being rather challenging, also the numerical simulation of screw compressors benefits from development and enhancement of numerical models, tools and methodologies. Differences between the real machine and the numerical model are inevitable, yet increasing accuracy and prognosis quality are desired by refining existing models and accounting for specific phenomena. Clearances within the working chamber (mainly intermesh clearance between rotors and axial and radial gaps between rotors and housing) strongly affect the flow characteristics, efficiency and thus the overall compressor performance. These clearances change under operating conditions because of thermal expansion or due to forces acting on the structure, whereas the clearance size is often only known for the reference state out of operation. The extent of deformation and the quantification of the resulting clearances is therefore of high interest in order to get the numerical model closer to real operating conditions. In this paper numerical simulation was used to determine the change in radial gap size between rotors and housing when the compressor is running and exposed to thermal and pressure loads. For a specific operating point, a 3D-CFD simulation for a 4-6 twin screw compressor with SRM profiles was conducted for the undeformed reference compressor geometry to calculate the flow field within the machine. Also, the temperature field within the housing and rotor solids was computed using the Conjugated Heat Transfer (CHT) method. The temperature and pressure fields were then submitted to the FEM solver to compute the deformation of rotors and housing. The results of this structural analysis served as input for a modification of geometry and numerical grids to account for the change in radial gap size. A re-run of the flow simulation in the deformed state enabled to quantify the impact on the machine performance and specific flow quantities. It could be shown that taking deformation into account, the volumetric efficiency is clearly affected. Commercial solvers from Ansys were utilized for solving fluid and structure. The spatial discretization of the fluid volume around the rotors was realized by employing pre-generated grids using the mesh generator TwinMesh. Here, the rotor deformation can be defined in dependence of the axial position. The mesh of the housing maintained unchanged for all CFD simulations as a resulting gap size was determined by considering housing and rotor deformation relative to each other.

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Cfd simulation of a two stage twin screw compressor including leakage flows and comparison with experimental data

Cited by 8 publications

References 0 publications

Experimental research on influence of interstage oil injection in a dual-motor-driven two-stage screw air compressor

Experimental research on influence of interstage oil injection in a dual-motor-driven two-stage screw air compressor

Computational Fluid Dynamics Evaluation of an Oil-flooded Screw Compressor

Investigation of radial gap size change under load and the impact on performance for a twin screw compressor using numerical simulation

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