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The system of centrifugal compressor GTU has several 2FSI subsystems: impeller, labyrinth seals (LS), dummies, etc. The article analyzes dependence of one subsystem the labyrinth seal on its diameter. The effect of this parameter on the wave processes occurring in labyrinth seals during vibrations of the rotor is studied. A solution is obtained for a nonstationary aeroelastic three-dimensional gas flow problem in deformable LS. The amplitude-frequency characteristics of the gas dynamic and vibration parameters of the LS CC of GTU are obtained. Time dependences of the gas-dynamical force and the work of gasdynamic forces in the LS zone at different rotor diameters are obtained. 1. Physical statement The computational model of the labyrinth seal was considered, which is a set of the LS gas-dynamic gap and the LS steel ring in a 3D statement. The change in the gas dynamic force in time, calculated through the pressure field acting directly on the rotor [1-6], was monitored. The rotor motion of the was described by the harmonic law with given amplitude and frequency [7-11]. When assigning the rotor oscillation frequency, the blade frequency and the rotational frequency were taken into account. The rotor geometric characteristics were varied and their influence on the wave processes occurring in the labyrinth seals during rotor vibrations was estimated. At the LS inlet and outlet, a differential pressure was set. Particular attention was paid to evaluation of wave processes in the circumferential direction [12-18]. As a parameter of the investigated dependences, the rotor diameter in the LS zone is adopted. 2. The solid staging The solid model (basic variant) is a circular gas-dynamic gap of LS with width 37 mm, height 500 μm and diameter 422 mm. The solid-state LS ring is a complex stepped construction (Figure 1). The construction material is steel, the pressure drop is not taken into account, the working medium is perfect gas. The plan for carrying out the computational experiment on studying resonances in the 2FSI subsystem “labyrinth seals” (LS) of GTU is shown in Table 1. The parameters vary with respect to the “basic variant”. IV International Conference on "Information Technology and Nanotechnology" (ITNT-2018) Table 1. The plan for the computational experiment. No of variant 1 (BV) 2 3 Drotor, mm 422 294 550 (BV) basic variant The calculation lasts 8.5 hours when examining the perfect gas and absence of pressure drop. Preliminary calculations have shown that the calculation time increases and reaches 48 hours for variants corresponding to real gases and presence of pressure drop in the LS. The amount of computational resources required is limited by the ANSYS capabilities for parallelizing the durability part of 2FSI calculations. Acceleration of calculations of the structure stress-strain state in the 2FSI statement was observed when only up to 8 cores (1 node) were used. With a further increase in the number of calculation cores, the count rate did not increase. Figure 1. Solid-state model of the 2FSI subsystem of the LS CC GTU. 3. The mesh model The minimum size of the finite elements of the mesh models of the LS ring and the gas-dynamic gap of the LS is 3.75 mm, the element type is hexahedral (Figure 2). For the feasibility of 2FSI calculations in the construction of mesh models of the gas dynamic region and durability region, it was ensured that the corresponding network elements coincide at the data transfer boundary from one type of analysis to another. a) b) Figure 2. The mesh model of the 2FSI subsystem of the LS CC GTU: (a) mesh model of the labyrinth seal ring; (b) mesh model of the gas-dynamic region of the labyrinth seal 4. Preparation and carrying out calculations on estimation of influence of LS geometrical characteristics on circumferential oscillations in 2FSI subsystem LS CC GTU In accordance with the plan, the influence of the LS geometric characteristics on circumferential oscillations in the 2FSI subsystem of the LS GTU is investigated. Time dependences of pressure, gas dynamic force, work of gas dynamic force and total displacements in the LS ring LU on the rotor diameter are obtained (Figure 3). Data Science L N Butymova and V Y Modorskii IV International Conference on "Information Technology and Nanotechnology" (ITNT-2018) 410

Analysis of dependence of the 2FSI subsystem parameters on the labyrinth seal diameter of the centrifugal compressor in the gas pumping unit