Abstract

The effect of the swirl clocking on three-dimensional nozzle guide vane (NGV) is investigated using computational fluid dynamics. The research reports the loss characteristics of leaned and swept NGVs and the influence of swirl clocking. The three-dimensional NGVs are built by stacking the same 2D profile along different linear axes, characterized by different angles with respect to the normal or radial direction: ε = −12° ~ +12° for the leaned and γ = −5° ~ +10° for the swept airfoils. A total of 40 models are analyzed to study the effects of lean and sweep on aerodynamic performance. To investigate the influence of swirl clocking, the analysis cases include the center of the swirl that was positioned at the leading edge as well as the middle of the passage. The prediction results show that the relationship of the changes in mass flow rate and throat area are not monotonic. Further observation confirms the redistribution of loading and flow angle under different lean and sweep angles; thus, three-dimensional design is a key influencing factor on aerodynamic performance. In the presence of swirl clocking, NGV performance is changed significantly and the findings offer new insight and opportunities to improve three-dimensional NGV airfoil design.

Highlights

  • The Nozzle Guide Vane (NGV) of a turbine experiences a highly turbulent combustion flow with a complicated swirl structure [1,2]

  • The results of straight lean with sweep are collected in Figure 8a, and compound lean with sweep are shown in Figure 8b, respectively

  • The dash-dotted line line is used to represent the alignment of the swirl center in the middle of passage

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Summary

Introduction

The Nozzle Guide Vane (NGV) of a turbine experiences a highly turbulent combustion flow with a complicated swirl structure [1,2]. The influence of lean, sweep and swirl on the three-dimensional aerodynamics of turbine passage is of great interest to researchers. Didlimitation not consider the lean and present study ai developed [21,22] It has been almost twenty years since the advanced computational gate the influence of the three-dimensionality of NGV on the turbine stag fluid dynamics (CFD) and experimental approach have been brought into turbomachinery more realistic operation conditions. While the previous research on lean and sweep reported its influence on threethe impact aerodynamics of swirl clocking onpassage, the stage. Canonsburg, PA), the addition, the study extended to include the swirl clocking by positioning the swirl core combustion gas and total to static pressure ratio are applied for theatcalculat the leading edge and passage center of NGV. 108 cases are analyzed for the present investigation

Computational
Definitions
Stage Performance with and without Swirl Clocking
Comparison
Combined Effect of Lean with Sweep
17. Comparison
Effect
The combustor exit swirl remains strong aligned theiscenter ofat passage
Downstream of NGV Passages and Mixing Plane
Downstream
24. Comparison
Stage Performance with Swirl Clocking
29. Comparison
Compound Lean with Swirl Clocking
Conclusions
Full Text
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