Quasi-2D Performance Analysis for Axial Compressors Based on Time-Marching Method

Zhang, Tong; Yang, Chen; Wu, Haidong; Li, Jinguang

doi:10.1051/jnwpu/20203810114

Cited by 2 publications

(3 citation statements)

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“…The underlying mathematical properties allow the present blade force model to inherently capture passage choking with no need of explicit choke criteria. Concerning condition 2) one can easily show that, conservation of the flux in equation (7) through an ideal discontinuity (with the same A and b on both sides) leads to the Rankine-Hugoniot equations for a normal shock in the relative velocity V. Such shock will be also captured by a suitable FV scheme for integration of equations ( 1) and ( 7) to (9).…”

Section: Passage Choking and Shocksmentioning

confidence: 99%

“…Equations ( 1) and (7) to (9) define the present meanline model. They interpret the quasi-1D flow in a blade region as a strictly 1D flow with only axial velocity but specific convective flux and source terms.…”

Section: Governing Flow Equationsmentioning

confidence: 99%

“…4 A more complex approach consists of modelling each blade row as a distribution of volume force which involves introduction of additional equations to those of the quasi-1D flow. [5][6][7] Whatever method is adopted to solve the blade force equations, it requires some more information on the essential blade geometry.…”

Section: Introductionmentioning

confidence: 99%

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Time-marching solution of transonic flows at axial turbomachinery meanline

Taddei

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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A new blade force model is coupled to quasi-one dimensional Euler equations for a variable geometry flowpath. After analytical inclusion of the blade force, the flow equations take a strictly one-dimensional form with specific expressions of the convective flux and blade load source terms. Regardless of the flow turning, that is simply achieved by the load source term as an explicit function of the blade camber, the new form describes a perfect analogy between the average flow inside a blade passage and strictly one-dimensional flows, especially concerning wave propagation. This property allows capture of passage choking and shocks. Other types of shock more important for turbomachinery analysis, like leading edge strong shocks in compressors and trailing edge weak shocks in choked turbines, are modelled by properly matching the new set of equations inside blade regions with the standard quasi-one dimensional equations outside. Upon specification of viscous losses and subsonic deviations fitted from experimental results, the model predicts the choke mass flow of a transonic compressor stage (NASA stage 37) at a 0.1% to 0.4% accuracy both in the absence and in the presence of the leading edge shock. This result supports the effectiveness of the leading edge shock model. The accuracy on choke mass flow would decrease to around 1% if empirical input was specified from open-literature experimental correlations. The model captures the typical trend of exit angle with total pressure ratio for a choked turbine (NASA Lewis two-stage). This result involves satisfactory prediction of not only choke mass flow, but also trailing edge shock loss and supersonic deviation. The complete turbine operational map in terms of shaft torque and pressure ratio is also re-obtained with noticeable accuracy except in strong off-design conditions, where experimental correlations likely fail.

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Section: Passage Choking and Shocksmentioning

confidence: 99%

Section: Governing Flow Equationsmentioning

confidence: 99%