Effects of Suction and Injection Purge-Flow on the Secondary Flow Structures of a High-Work Turbine

Schuepbach, P.; Abhari, Reza S.; Rose, Martin G.; Germain, T.; Raab, I.; Gier, Jochen

doi:10.1115/gt2008-50471

Cited by 13 publications

(14 citation statements)

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“…The result showed that the tangential difference of the mainstream and cooling flow was the main reason for flow loss, and pre-swirling was helpful to reduce the negative effect. Similar results were also found by Schuepbach et al 17 and Cui and Tucker. 18 Numerical simulation of Andreini et al 19 indicated that the cooling flow decreased the tangential speed of the mainstream, which consequently reduced the incidence angle of the downstream rotor near the turbine hub wall.…”

Section: Introductionsupporting

confidence: 91%

Experimental study on the aerodynamic influence of purge flow in a turbine cascade with different mainstream incidence angles

Zhao

2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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Demand for high reliability and long life of modern turbine requires that turbine components should be cooled adequately. The cooling flow purged into the rotor-stator disk cavity will inevitably interact with the mainstream. The current paper mainly focuses on the aerodynamic influence of cooling flow on the secondary flows in the mainstream. Both particle image velocimetry and blade wall pressure measurement were utilized to study the flow field within the turbine blade passage under different mainstream incidence angles and purge flow rates. The purge flow was found to promote the development of the passage vortex by inducing vortices which can enhance the vorticity of the passage vortex. In addition, the mainstream incidence angle also has an impact on the development of the passage vortex through affecting the blade loading and the horseshoe vortex. Furthermore, the transient results demonstrate that the time-averaged vortex is the superposition of large number of transient vortices, and the purge flow causes more transient vortices with large size and high strength.

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Section: Introductionsupporting

confidence: 91%

Experimental study on the aerodynamic influence of purge flow in a turbine cascade with different mainstream incidence angles

Zhao

2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…7 They determined that the hub secondary flo ws have a larger radial exten t if the seal air mass flow is increase fro m 0.14% MF to 0.9%MF. In addition the total-to-total efficiency drops by 0.6% if the seal air mass flow is increased.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Interaction between Rim Seal and Main Annulus Flow in a Four Stage Low-Pressure Axial Turbine

tao¹

2015

22nd AIAA Computational Fluid Dynamics Conference

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A steady three-di mensional numerical calculation is performed in order to investigate the effect of rim sealing flow in a four-stage low pressure axial turbine. Mesh generati on of the main flow domai n and the sealing fl ow domain is performed with the structured multi -bl ock grid. The fini te vol ume flow s ol ver ANS YS CFX 15.0 with SST k-ω turbulence model together with the transitional fl ow model is employed. The numerical approach is vali dated by comparing the results of calcul ati ons to measurement data on the design poi nt. The fl ow field and secondary fl ow in the turbine wi th and without the sealing flow injection from rim seals are studied numerically. The results suggest that the sealing flow pl ays a major role in turbine performance and main structure of flow fields. It leads to a decreased turbine efficiency, to altered inci dence angles and to an intensificati on of secondary flow structure. The rim seal leakage vortex generating at the ri m seals interface enhances the passage vortex and results in the added fl ow l oss. This proves that the effects of the sealing flow on turbine rotor performance are very l arge and shoul d be considered in turbine design. In addi tion, an enhanced understanding of the interaction between the sealing flow and the main annulus flow are obtained.Nomenclature IR = injection rat io MF = mass fraction [kg/kg] Ma = Mach number m = mass flow [kg/s] m s = sealing mass flo w [kg/s] m m = mainstream mass flow [kg/s] R = rotor S = stator t = tangential direction U = rotor speed [m/s] V = absolute velocity [m/s] W = relative velocity [m/s] x = axial d irection y+ = non-dimensional wall d istance η = efficiency

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“…The effectiveness, and hence mixing, in the rim seal region was shown to be principally dependent on the sealing mass flow rate, regardless of the seal configuration used inboard to protect the wheelspace. Schuepbach et al 13 conducted an experimental study to show the flow mechanisms that were caused by injection through the rim seal. The injection caused the turbine efficiency to deteriorate by about 0.6%.…”

Section: Introductionmentioning

confidence: 99%

“…Schuepbach et al. 13 conducted an experimental study to show the flow mechanisms that were caused by injection through the rim seal. The injection caused the turbine efficiency to deteriorate by about 0.6%.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the flowfield on a vaneless counter-rotating turbine with seal cavity flow ejection

Sui

Zhao

Xiang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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The sealing of the rotor-rotor gap and rotor disk cooling are vital to the safe operation of the vaneless counter-rotating turbine(VCRT). In order to quantifies the influence of the wheel-space cavity flow on the VCRT aerodynamic performance, and to improve turbine efficiency of the VCRT at certain rim seal ejection rates, numerical studies which considered the effects of rotor-rotor rim seal flow ejection are carried out in this paper. The three dimensional unsteady computational fluid dynamic analysis of a VCRT at the engine conditions are performed, and the seal flow ejected downstream of the high pressure rotor row at six sealing flow rate are modeled. The interaction among the high pressure rotor trailing shock wave, the downstream secondary flow and the seal flow has been studied and quantitatively characterized as a function of the purge ejection rate. Numerical results show that seal flow- mainstream flow interaction is entirely dominated by the high pressure rotor trailing edge shock at the hub, low pressure hub passage vortex and the mixing of the sealing flow from wheelspace and mainstream. When the mass flow rate of the coolant is smaller than some threshold value, the shock loss of the high pressure rotor and hub secondary flow loss of the low pressure rotor are decreased with the increasing of the coolant mass flow rate. It causes that the VCRT efficiency is gradually increased. On condition that the amount of the seal flows is beyond the threshold value, the key roles in modification of the VCRT performance are changed. The increment of the hub secondary flow loss and the mixing loss are gradually larger than the decrement of the shock loss. As a result, the turbine efficiency gradually decreases.

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Effects of Suction and Injection Purge-Flow on the Secondary Flow Structures of a High-Work Turbine

Cited by 13 publications

References 0 publications

Experimental study on the aerodynamic influence of purge flow in a turbine cascade with different mainstream incidence angles

Experimental study on the aerodynamic influence of purge flow in a turbine cascade with different mainstream incidence angles

Numerical Simulation of the Interaction between Rim Seal and Main Annulus Flow in a Four Stage Low-Pressure Axial Turbine

Investigation of the flowfield on a vaneless counter-rotating turbine with seal cavity flow ejection

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