Study of modeling unsteady blade row interaction in a transonic compressor stage part 1: code development and deterministic correlation analysis

Liu, Yangwei; Liu, Baojie; Lu, Lipeng

doi:10.1007/s10409-012-0049-z

Cited by 13 publications

(9 citation statements)

References 27 publications

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“…From the above analysis it is inferred that, the distributions of deterministic stress and deterministic enthalpy are quite different from that in compressors [25]. Usually in compressors, the deterministic stress and enthalpy have large magnitudes at the rotor-stator interface and decrease rapidly in the flow direction downstream of the interface; however, there is no obvious similar behavior in the turbine.…”

Section: Deterministic Stress/enthalpy Studymentioning

confidence: 84%

“…Modeling deterministic correlations is the key to close the average-passage equation system which could provide a rigorous mathematical framework for accounting for the unsteady blade row interaction in steady state calculation by introducing deterministic correlations. Liu et al [24,25] studied the deterministic stress and enthalpy correlations in compressors, which could be valuable for modeling deterministic correlations. However, few studies focused on deterministic correlations in turbines.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Unsteady Flow Interactions in a Transonic High Pressure Turbine Using Nonlinear Harmonic Method

et al. 2018

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Abstract:The performance of a transonic high pressure turbine is mainly influenced by the unsteady interactions associated with the passing blades. In this paper, the unsteady flow interactions in a transonic turbine have been numerically investigated using the nonlinear harmonic (NLH) method in comparison with the steady and unsteady Reynolds-averaged Navier-Stokes (RANS). The comparison shows that the NLH method using three harmonics could capture the main unsteady flow interactions efficiently with about seven times smaller computational cost than the unsteady RANS, resulting in a more accurate time-averaged flow than for steady RANS. However, the continuity of the flow variables across the rotor-stator interface has shown some discrepancies compared with the unsteady RANS, which can be further satisfied by increasing the numbers of harmonics. The unsteady interactions are analyzed in detail; the results show that the wake and trailing edge shock from the upstream stator are the major sources of unsteadiness in the downstream rotor passage. The stator trailing edge shock impinges on the suction side of the passing rotor blades and generates pressure waves. These pressure waves are periodically reflected back to trigger the stator wake shedding. These waves are strong enough to travel through the rotor passage, and eventually affect the flow at the rotor's trailing edge. The stator wakes are chopped by the downstream rotor, and travel through the rotor passage. This significantly enhances the unsteadiness of the flow near the rotor trailing edge. Lastly, the deterministic stresses and enthalpy distributions extracted from the NLH method have revealed that the effects of the unsteadiness are relatively weaker in the axial direction. Furthermore, the deterministic correlations analysis has shown that, some empirical deterministic correlations models based on the decay concept of compressors are not suitable for turbines.

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Section: Deterministic Stress/enthalpy Studymentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Investigation of Unsteady Flow Interactions in a Transonic High Pressure Turbine Using Nonlinear Harmonic Method

et al. 2018

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“…et al that, in general, unsteady simulation is recommended to compute at least 10 to 20 time steps per period. To obtain a more accurate result, 20 steps per passage were chosen [38]. Hence, 300 steps were able to cover a whole period of impeller revolution.…”

Section: Discretization Methods and Boundary Conditionsmentioning

confidence: 99%

Investigation on Unsteady Flow Characteristics of a SCO2 Centrifugal Compressor

et al. 2017

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Supercritical carbon dioxide (SCO 2 ) is a vital working fluid in the application of power units and its high density helps to achieve a compact mechanical structure. Centrifugal compressors are of vital use in various kinds of equipment. In this paper, a SCO 2 centrifugal compressor of large input power and mass flow rate is designed and numerically investigated. A thorough numerical analysis of the unsteady flow field in the centrifugal compressor is performed in ANSYS-CFX. The computation adopts hexahedral mesh, finite volume method, and the RNG k-ε two-equation turbulence model. Streamlines, temperature, pressure, and Mach number distributions at different time steps in one revolution period are covered to present the unsteady effect of turbomachinery. Meanwhile, the force on a single rotor blade is monitored to investigate the frequency components of exciting force, thus providing the foundation for vibration analysis. Moreover, the torque, output power, pressure ratio, and isentropic efficiency in the steady and the unsteady time-averaged condition are calculated and compared with the design condition to measure the validity of the design. In summary, the unsteady computation result reveals that the unsteady flow characteristics are prominent in the designed compressor and the design of impeller and diffuser meet the requirement.

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“…Hence, more research work for modeling the DC should be conducted. In our previous studies, the distribution characteristics of DC and the effects of DC on time-averaging simulation were conducted [12][13][14][15][16]. We found that the timeaveraging simulation with axisymmetric DC can take into account the major part of the unsteady effects on spanwise redistribution.…”

Section: Introductionmentioning

confidence: 97%

“…In recent years, many efforts have been made and some DC models have been proposed [3][4][5][6][7][8][9][10][11]. Some DC models [3][4][5]8] are axisymmetric based on a hypothesis that the purely unsteady fluctuations are negligible, though the DC is not uniform in circumferential direction and the gradients are large in some regions in the blade passage [12]. Adamczyk et al [3] proposed the first model using overlapping grids for all blade rows without the interface planes.…”

Section: Introductionmentioning

confidence: 99%

An Exponential Decay Model for the Deterministic Correlations in Axial Compressors

Liu

Tang

Liu

et al. 2019

Journal of Turbomachinery

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The unsteady blade row interaction (UBRI) is inherent and usually has a large effect on performance in multistage axial compressors. The effect could be considered by using the average-passage equation system (APES) in steady-state environment by introducing the deterministic correlations (DC). How to model the DC is the key in APES method. The primary purpose of this study is to develop a DC model for compressor routine design. The APES technique is investigated by using a 3D viscous unsteady and time-averaging Computational fluid dynamics (CFD) flow solver developed in our previous studies. Based on DC characteristics and its effects on time-averaged flow, an exponential decay DC model is proposed and implemented into the developed time-averaging solver. Steady, unsteady, and time-averaging simulations are conducted on the investigation of the UBRI and the DC model in the first transonic stage of NASA 67 and the first two stages of a multistage compressor. The DC distributions and mean flow fields from the DC model are compared with the unsteady simulations. The comparison indicates that the proposed model can take into account the major part of UBRI and provide significant improvements for predicting compressor characteristics and spanwise distributions of flow properties in axial compressors, compared with the steady mixing plane method.

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Study of modeling unsteady blade row interaction in a transonic compressor stage part 1: code development and deterministic correlation analysis

Cited by 13 publications

References 27 publications

Investigation of Unsteady Flow Interactions in a Transonic High Pressure Turbine Using Nonlinear Harmonic Method

Investigation of Unsteady Flow Interactions in a Transonic High Pressure Turbine Using Nonlinear Harmonic Method

Investigation on Unsteady Flow Characteristics of a SCO2 Centrifugal Compressor

An Exponential Decay Model for the Deterministic Correlations in Axial Compressors

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