Reducing cross-flow vibrations of underflow gates: Experiments and numerical studies

Abstract To investigate the application of ribbed cross-flow coolant channels with film hole effusion and the effects of the internal cooling configuration on film cooling, experimental and numerical studies are conducted on the effect of the relative position of the film holes and different orientation ribs on the film cooling performance. Three cases of the relative position of the film holes and different orientation ribs (post-rib, centered, and pre-rib) in two ribbed cross-flow channels (135° and 45° orientation ribs) are investigated. The film cooling performances are measured under three blowing ratios by the transient liquid crystal measurement technique. A RANS simulation with the realizable k-ε turbulence model and enhanced wall treatment is performed. The results show that the cooling effectiveness and the downstream heat transfer coefficient for the 135° rib are basically the same in the three position cases, and the differences between the local effectiveness average values for the three are no more than 0.04. The differences between the heat transfer coefficients are no more than 0.1. The “pre-rib” and “centered” cases are studied for the 45° rib, and the position of the structures has little effect on the film cooling performance. In the different position cases, the outlet velocity distribution of the film holes, the jet pattern and the discharge coefficient are consistent with the variation in the cross flow. The related research previously published by the authors showed that the inclination of the ribs with respect to the holes affects the film cooling performance. This study reveals that the relative positions of the ribs and holes have little effect on the film cooling performance. This paper expands and improves the study of the effect of the internal cooling configuration on film cooling and makes a significant contribution to the design and industrial application of the internal cooling channel of a turbine blade.

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Experimental and numerical studies on flow and torque mechanisms of open cross-flow hydraulic turbine

Energy for Sustainable Development ◽

10.1016/j.esd.2021.10.005 ◽

2021 ◽

Vol 65 ◽

pp. 107-116

Author(s):

T. Wang ◽

H. Shikama ◽

T. Yamagata ◽

N. Fujisawa

Keyword(s):

Cross Flow ◽

Hydraulic Turbine ◽

Numerical Studies

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Experimental and numerical studies on the discrete noise about the cross-flow fan with block-shifted impellers

Applied Acoustics ◽

10.1016/j.apacoust.2010.07.002 ◽

2010 ◽

Vol 71 (12) ◽

pp. 1142-1155 ◽

Cited By ~ 5

Author(s):

You Li ◽

Hua Ouyang ◽

Jie Tian ◽

Zhaohui Du ◽

Zhiming Zheng

Keyword(s):

Cross Flow ◽

Numerical Studies ◽

The Cross ◽

Cross Flow Fan

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Rotor-Tip Leakage: Part II — Design Optimization Through Viscous Analysis and Experiment

Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery ◽

10.1115/81-gt-72 ◽

1981 ◽

Cited By ~ 5

Author(s):

A. R. Wadia ◽

T. C. Booth

Keyword(s):

Stream Function ◽

Discharge Coefficient ◽

Cross Flow ◽

Turbine Rotor ◽

Leakage Flow ◽

Tip Leakage ◽

Rotating Blades ◽

Numerical Studies ◽

Coolant Injection ◽

Blade Tip

Blade tip losses represent a major efficiency penalty in a turbine rotor. These losses are presently controlled by maintaining close tolerances on tip clearances. This two-part paper outlines a new methodology for predicting and minimizing tip flows, and focuses on the control of tip leakage through minimization of the discharge coefficient to control the normal leakage flow component. Minimization of the discharge coefficient was achieved through viscous analysis and was supported by discharge-rig testing. The analysis for the discharge cross-flow used a stream function-vorticity formulation. Support testing was conducted with a newly developed water table discharge rig in which tip-coolant discharge could also be simulated. Experimental and numerical tip-leakage results are presented on a discharge coefficient parameter for five different tip configurations. In addition, numerical studies were conducted for stationary and rotating blades with and without tip coolant injection.

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Experimental Evaluation of Pure In-Line Vortex Induced Vibration (VIVx) of Low Mass-Damping Ratio Cylinder

Volume 2: CFD and VIV ◽

10.1115/omae2016-54374 ◽

2016 ◽

Author(s):

Mohammad Mobasher Amini ◽

Antonio Carlos Fernandes

Keyword(s):

Reynolds Number ◽

Circular Cylinder ◽

Damping Ratio ◽

Cross Flow ◽

Current Channel ◽

Number Range ◽

Vortex Induced Vibration ◽

Numerical Studies ◽

Lower Amplitude ◽

Low Mass

Numerous experimental and numerical studies have been carried out to better understand and to improve prediction of cylinder VIV (vortex Induced Vibration) phenomenon. The behavior of cylinder due to in-line vibration (VIVx) has been neglected in the earlier studies because of its lower amplitude in comparison with cross flow vibration (VIVy). However, some researchers have studied VIVx in 2DOF along with VIVy. Recent investigations show that response amplitude of structure caused by VIVx is large enough to bring it to consideration. This study focuses on understanding the origin and prediction of VIVx amplitude exclusively in 1DOF and subcritical flow regime. The experiments were performed in current channel on bare circular cylinder with low mass-damping ratio in Reynolds number range Re = 10000 ∼ 45000.

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Internal Flow and Noise Investigations About the Cross-Flow Fan With Different Blade Angles

Volume 7: Turbomachinery, Parts A, B, and C ◽

10.1115/gt2010-23280 ◽

2010 ◽

Author(s):

You Li ◽

Hua Ouyang ◽

Jie Tian ◽

Zhiming Zheng ◽

Zhaohui Du

Keyword(s):

Relative Velocity ◽

Numerical Solutions ◽

Cross Flow ◽

Internal Flow ◽

Flow Patterns ◽

Far Field ◽

Numerical Studies ◽

Aerodynamic Performances ◽

Field Noise ◽

Cross Flow Fan

The experimental and numerical studies have been carried out to investigate the flow and the noise characters of the three impellers with different blade angles in a cross-flow fan (CFF). Firstly, the aerodynamic performances of the fan with these impellers are obtained experimentally and the averaged flow patterns inside the impellers are measured by the three-hole probe. Secondly, the far-field noise generated by CFF with different impellers has been measured in a semi-anechoic chamber under different throttling conditions. Thirdly, the two-dimensional unsteady CFD simulations have been performed by commercial software. The internal flow patterns influenced by the different blade angles have been summarized through the computational results. The accuracy of the calculations is validated by the corresponding experimental ones. The detail analysis has been carried out on the unsteady vortex flow properties of the three impellers, which is considered to be the main factor that influences the aerodynamic and aeroacoustic performance of the CFF. Finally, the relative far field noise generated by different impellers are evaluated by an empirical formula based on the assumption that the total sound pressure levels are proportional to the sixth power law of the relative velocity on the outer and inner circumferences of the impeller. The circumferential distributions of relative velocity are provided from the numerical solutions. The varying trends of predicted results agree well with the actual relative noise of the CFF with three different impellers.

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