1998 Turbomachinery Committee Best Paper Award: An Experimental Study of Tip Clearance Flow in a Radial Inflow Turbine

Dambach, R.; Hodson, H. P.; Huntsman, I.

doi:10.1115/1.2836716

Cited by 31 publications

(4 citation statements)

References 11 publications

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“…The rotor tip clearance loss is evaluated by the model presented by Dambach [29], which considers the interaction of axial clearance flow and radial clearance flow, as Equation 8,…”

Section: Automated Preliminary Design Methodologymentioning

confidence: 99%

An Integrated Design and Optimization Approach for Radial Inflow Turbines—Part I: Automated Preliminary Design

Deng

Shao²,

et al. 2018

Applied Sciences

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An integrated design and optimization approach was developed for radial inflow turbines, which consists of two modules, an automated preliminary design module, and a flexible three-dimensional multidisciplinary optimization module. In this paper, the first module about the automated preliminary design approach was presented in detail and validated by the experimental data. The approach employs a genetic algorithm to explore the design space defined by the loading coefficient, flow coefficient, and rotational speed. The aim is to obtain the best design scheme with high aerodynamic performance under specified constraints and to reduce the dependency on human experiences when designing a radial inflow turbine. The validation results show that the present approach is able to get the optimal design and alleviate the dependence on the designer’s expertise under specified constraints at the preliminary design stage. Furthermore, the optimization results indicate that using the present optimization approach the total-to-static efficiency of the optimized T-100 radial inflow turbine can be increased by 1.0% under design condition and the rotor weight can be decreased by 0.35 kg (26.7%) as compared with that of the original case.

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“…The rotor tip clearance loss is evaluated by the model presented by Dambach [29], which considers the interaction of axial clearance flow and radial clearance flow, as Equation 8,…”

Section: Automated Preliminary Design Methodologymentioning

confidence: 99%

An Integrated Design and Optimization Approach for Radial Inflow Turbines—Part I: Automated Preliminary Design

Deng

Shao²,

et al. 2018

Applied Sciences

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“…Despite the additional endwall losses from the separation, the stage performance was still improved due to the reduction of the tip leakage losses. However, as mentioned in [15], the tip leakage mechanism in an RFT is different from an axial turbine because of the variation of radius on the shroud side. Therefore, there is no guarantee that such improvement in [14] will also be seen in an RFT.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Performance Impact of Stator Tilting Endwall Designs on a Mixed Flow Turbine

Fridh

Morrison

Ren

et al. 2021

IJTPP

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This paper numerically investigates stator endwall designs for a mixed flow turbine. One key design parameter studied is the tilting angle of the stator endwall. By examining stator designs with different tilting angles, the aim of this paper is to improve the efficiency of the studied mixed flow turbine at low velocity ratio working conditions. The performance curve at the design speed was chosen for the comparison between the baseline design and the tilted endwall designs. First, the numerical predictions for the baseline design were validated with experimental data. Then, to understand the mechanism of the performance variation between the different designs, the internal flow field was analyzed in detail. It was found that the tilting stator endwall could form a geometric “kink” in the endwall profiles. On the shroud side, certain designs with such kink caused local flow separations upstream the rotor leading edge. This separation could have the effect of reducing the intensity of the tip leakage vortex and the exit kinetic energy losses at the rotor outlet and may also improve the performance of the exhaust diffuser. As a result, the peak of the efficiency curve shifted toward lower velocity ratio. If the turbine stage incorporated a downstream exhaust diffuser, the optimal design in this study showed a shift of the velocity ratio of the peak efficiency point from 0.62 to 0.60 compared with the baseline. The maximum efficiency improvement was 1.3% points, which occurred at low velocity ratio. Meanwhile, the peak efficiency was 0.2% points higher than the baseline. If the exhaust diffuser was removed, a similar shift of the efficiency curve was observed but less efficiency gain was achieved at the low velocity ratio condition. A preliminary unsteady simulation was also conducted for the optimal design in this study.

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“…A large number of studies have developed flow models and loss models for tip leakage in axial turbine to better understanding the nature of tip leakage flow. 1,2 And tip leakage mass flow rate and leakage flow loss has been quantified. 3,4 The flow loss caused by tip clearance in a turbine accounts for more than one-third of the total loss.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigations on leakage performance and flow mechanism of spiral groove seal for shrouded blade in axial turbine

Xiong

Zhu

Wang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Flow field of shroud leakage flow for a single-stage axial turbine has been investigated in this article. The spiral groove seal (SGS) is adopted for shrouded rotor blade to reduce tip leakage and improve turbine aerodynamic performance. A series of three-dimensional (3D) computational fluid dynamics (CFD) simulations are performed to investigate leakage characteristics and flow mechanism of various configurations with different angle, depth, width, and grooves number of the SGS. The original staggered labyrinth seal (LS) is also calculated for comparison. The results illustrate that small spiral groove angle can create more axial flow resistance; meanwhile, it will increase grooves number existing in the axial direction. Groove depth and tooth width will influence the number, shape, and strength of vortex in the groove. The leakage mass flow can be reduced by 36% and isentropic efficiency of the turbine can be increased by 0.26% when spiral groove angle, depth, and width of the SGS are 1.5°, 1.8 mm, and 0.8 mm, respectively. Overall, the optimal SGS can influence vortex generation and enhance energy dissipation in shroud cavity to reduce the leakage and suppress mixing loss of leakage flow with the main flow to some extent. It can be attributed to the combination of throttling effect and pumping effect of the SGS that realize leakage reduction and efficiency improvement. As a result, the SGS can effectively improve tip leakage flow of shrouded blade in axial turbine.

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1998 Turbomachinery Committee Best Paper Award: An Experimental Study of Tip Clearance Flow in a Radial Inflow Turbine

Cited by 31 publications

References 11 publications

An Integrated Design and Optimization Approach for Radial Inflow Turbines—Part I: Automated Preliminary Design

An Integrated Design and Optimization Approach for Radial Inflow Turbines—Part I: Automated Preliminary Design

Numerical Investigation of the Performance Impact of Stator Tilting Endwall Designs on a Mixed Flow Turbine

Numerical investigations on leakage performance and flow mechanism of spiral groove seal for shrouded blade in axial turbine

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