An Experimental Verification of a New Design for Cantilevered Stators With Large Hub Clearances

Lange, Martin; Vogeler, Konrad; Mailach, Ronald; Gomez, Sergio Elorza

doi:10.1115/1.4007612

Cited by 17 publications

(11 citation statements)

References 10 publications

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“…Wang, Chen, Wu, and Ren (2014) have shown good agreements of compressor performance maps between the computed results and the experimental data in a counter-rotating axial compressor when using the Spalart-Allmaras model. Lange, Vogeler, Mailach, and Gomez (2013) have shown that the NUMECA FINE-Turbo-computed blade pressure distributions have quite good agreement with the experiment. In addition, the separations predicted by the Spalart-Allmaras model are validated by using the k-model, indicating that the achieved results are not the function of the turbulence model.…”

Section: Cfd Validationssupporting

confidence: 54%

Using forward end-sweep to reduce transonic cantilevered stator losses to improve compressor performance

Pan

2018

Engineering Applications of Computational Fluid Mechanics

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The complicated flows in a transonic cantilevered stator would cause serious aerodynamic losses and reducing these losses would contribute much to improving the overall aerodynamic performance of a compressor. The paper conducts an overview study of the potential aerodynamic losses in a transonic cantilevered stator and presents a systematic numerical study for the effects of forward end sweep on reducing aerodynamic losses. A 2-D stator blade is used to throw light upon the physical mechanism of the forward end sweep on reducing the losses. At the casing region, forward end sweep has led to a redistribution of the blade load along the chordwise direction, higher in the front part and lower in the rear part. This result leads to a lower pressure gradient from the 30% chord location to the trailing edge and can be beneficial for the reduction of the corner separation. At the hub region, on one aspect, forward end sweep reduces both the peak Mach number and the size of the high-Ma region of the blade suction surface, thus decreasing the shock loss near the hub. On the other aspect, it also reduces the peak load and the strength of the leakage vortex, therefore alleviating the flow blockages. Simultaneously, the forward end sweep is applied to a commercial and high-performance multistage compressor to further validate its feasibility. When the technique is applied to the transonic first four stator rows, an improvement of adiabatic efficiency is achieved by ∼ 0.85% and the compressor stable operating range is slightly increased. The results suggest that the forward end-swept transonic cantilevered stators have a significant potential for reducing the stator losses. They would provide guidelines to advance the cantilevered stator design and further improve the compressor aerodynamic performance.

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Section: Cfd Validationssupporting

confidence: 54%

Using forward end-sweep to reduce transonic cantilevered stator losses to improve compressor performance

Pan

2018

Engineering Applications of Computational Fluid Mechanics

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“…15 and 16 is scaled using Eq. (8). The non-dimensional coordinate x rel and y rel are normalized with the axial chord length, starting at the leading edge.…”

Section: Penny Cavity Flowmentioning

confidence: 99%

“…VSVs for both designs exist, as shown, for example, by Escuret [7]. The hub clearance of cantilevered stator vanes and the development of the hub clearance vortex have been investigated, for example, by Lange [8]. Shrouded VSVs are mounted on the hub on an inner ring.…”

Section: Introductionmentioning

confidence: 99%

Variable Stator Vane Penny Gap Aerodynamic Measurements and Numerical Analysis in an Annular Cascade Wind Tunnel

Pohl

Janssen

Jeschke

et al. 2020

JGPP

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This paper presents detailed measurements and post-test simulations of the penny cavity leakage flow and its interaction with the mainstream flow in an annular cascade wind tunnel. The annular cascade wind tunnel consists of a single row of 30 variable stator vanes, derived from a high-pressure compressor stator with inner and outer vane disks, called pennies, whichwhen assembled in the hub and casing wallsleave cylindrical-shaped ring gaps called penny cavities. The wind tunnel runs at a Mach number of 0.34 at the stator inlet and a Reynolds number of 3.82 x 10 5 based on axial chord length at 50% span. Two different penny gap sizes on the hub are compared to a reference case without a penny gap. Detailed 2D-traverses were performed with multi-hole pressure and hot-wire-probes covering 2.5 passages in the inflow and outflow of the stator row. Pressure taps were embedded in the airfoil surface and inside the penny cavity. Surface oil flow measurements were conducted with different colors for the vane suction side, pressure side, hub and the penny cavity to detect the secondary flow phenomena. Reynoldsaveraged Navier-Stokes (RANS) simulations, using the measured boundary conditions, were compared to experimental data. As a result, a relative increase in the total pressure loss coefficient of 1.9% for the nominal and 6.8% for the double penny gap was measured compared to no-penny cavity. The additional penny losses are limited to the lower 40% span. The post-test simulations are in good agreement with the measurements, showing that the outflow from the penny cavity on the suction side generates vortices, which cause additional losses. The penny vortices are detected in the outlet plane by an increase in turbulence intensity and streamwise vorticity. However, the additional penny losses are overestimated in the simulation by up to 7.3%. A change in the pressure fields with an increasing penny gap size, both around the airfoil and inside the penny cavity, can be seen in the numerical and experimental results. The outflow regions of the penny cavity, estimated by simulations, are confirmed by the results of the surface oil flow measurements. In summary, this paper consolidates previous numerical analyses carried out by the authors [13-16] on penny cavity leakage flow effects with experimental data for different penny gap sizes.

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“…The distributions of averaged circumferential static pressure coefficient, C p , at five spanwise points of the rotor and stator for the prototype and model A at design point are shown in Figures 5 and 6. C p is defined as C p = P P total,in (11) where P and P total,in denote the surface static pressure and the total pressure at inlet. The static pressure distributions of numerical results of prototype and model A are shown in Figure 5.…”

Section: Comparison Of the Prototype And Scaled-up Low-speed Model Amentioning

confidence: 99%

“…Lyes optimized the high-pressure compressor through research on blade bending and sweeping based on a low-speed model [7], which was also used for sweep and dihedral blading studies by RR Company and Cambridge University [8,9]. Besides, Boos and Lange also carried out a high loaded blading investigation on this large-scale, low-speed compressor [10,11]. Zhang to reached performance optimization of a low-speed axial rotor by three-dimensional (3D) optimization with numerical computation, and then the experiments were carried out for validation of the numerical results [12,13].…”

Section: Introductionmentioning

confidence: 99%

Research on the Application of Partial Similarity for a 1-1/2 Axial Compressor

2020

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In this paper, a method based on the partial similarity principle is presented to improve the aerodynamic design with low cost and high accuracy for a 1-1/2 axial compressor. By means of this method, during the process of a similar design, the machine Mach number and flowrate coefficient are maintained. The flow similarity between the prototype and its large-scaled alternative was observed, according to a detailed analysis of flow fields of rotor and stator. As well, the relative discrepancies of isentropic efficiency and pressure ratio between two models are 1.25% and 0.4% at design point, respectively. Besides, their performance curves agreed very well in the whole operating range. Moreover, it was also found that the flow similarity between the two models can be maintained under unsteady working conditions. Thereafter, in order to investigate the impact of stability optimization method on the similarity principle, casing treatment with single circumferential groove was applied to these two models. The flow similarity was still maintained and the flowrate near the stall was reduced about 1.1% with negligible deterioration of the overall performance.

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An Experimental Verification of a New Design for Cantilevered Stators With Large Hub Clearances

Cited by 17 publications

References 10 publications

Using forward end-sweep to reduce transonic cantilevered stator losses to improve compressor performance

Using forward end-sweep to reduce transonic cantilevered stator losses to improve compressor performance

Variable Stator Vane Penny Gap Aerodynamic Measurements and Numerical Analysis in an Annular Cascade Wind Tunnel

Research on the Application of Partial Similarity for a 1-1/2 Axial Compressor

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