Effect of Inlet Flow Angle on the Erosion of Radial Turbine Guide Vanes

1990 ◽  
Vol 112 (1) ◽  
pp. 64-70 ◽  
Author(s):  
H. Eroglu ◽  
W. Tabakoff
Keyword(s):  
Particle Size ◽  
Incidence Angle ◽  
Particle Dynamics ◽  
Particulate Flow ◽  
Inlet Flow ◽  
Flow Angle ◽  
Guide Vanes ◽  
Radial Turbine ◽  
The Impact ◽  
Radial Turbines

The results of an investigation of the particle dynamics and the blade erosion at the impact locations in radial turbine guide vanes are presented. Attention is focused in particular on the effect of inlet flow angle on the erosion of the blades, since the flow entering the guide vanes usually has an incidence angle due to the upstream scroll geometry. The total erosion per blade is calculated as a function of inlet flow angle for three different particle diameters, which are 5, 15, and 60 μm, respectively. According to the results of this investigation, for each particle size there is an inlet flow angle for minimum erosion of the guide vanes. This fact has to be accounted for in the design of radial turbines operating in particulate flow environments.

scholarly journals Effect of Inlet Flow Angle on the Erosion of Radial Turbine Guide Vanes

1989 ◽  
Author(s):  
Hasan Eroglu ◽  
Widen Tabakoff
Keyword(s):  
Particle Size ◽  
Incidence Angle ◽  
Particle Dynamics ◽  
Particulate Flow ◽  
Inlet Flow ◽  
Flow Angle ◽  
Guide Vanes ◽  
Radial Turbine ◽  
The Impact ◽  
Radial Turbines

The results of an investigation of the particle dynamics and the blade erosion at the impact locations in radial turbine guide vanes are presented. The attention is focused in particular on the effect of inlet flow angle on the erosion of the blades, since the flow entering the guide vanes usually has an incidence angle due to the upstream scroll geometry. The total erosion per blade is calculated as a function of inlet flow angle for three different particle diameters which are 5, 15 and 60 microns respectively. According to the results of this investigation, for each particle size there is an inlet flow angle for minimum erosion of the guide vanes. This fact has to be accounted for in the design of the radial turbines operating in particulate flow environments.

Effect of Incidence Angle on Gas Turbine First-Stage Nozzle Guide Vane Leading Edge and Gill Region Film Cooling

2012 ◽  
Author(s):  
Yang Zhang ◽  
Xin Yuan
Keyword(s):  
Film Cooling ◽  
Incidence Angle ◽  
Leading Edge ◽  
Inlet Flow ◽  
Flow Angle ◽  
Cooling Performance ◽  
Guide Vanes ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes ◽  
Compound Angle

The nonuniformity of the Hp turbine inlet flow field put forward higher requirements for NGV (Nozzle Guide Vanes) leading edge and gill region film cooling. The assumption of design condition in most of the experiments couldn’t reflect the true operation environment in the Hp turbine NGV. The factor of off-design condition was incorporated into the experiment in this research. The GE-E3 Hp turbine nozzle guide vanes were used in the experiment to investigate the cooling performance of injection from leading edge and gill region with inlet Reynolds numbers of Re = 3.5×105 and inlet Mach number of Ma = 0.1. The compound angle fan-shaped film cooling hole configuration was applied. The cooling characteristics at off-design condition were analyzed and compared in the paper. The leading edge and gill region film cooling performance was assessed with the incidence angle varying from i = −10deg to i = +10deg. The blowing ratio varying from M = 0.7 to M = 1.3, was also selected as an experimental variable. Film cooling effectiveness distribution was measured using PSP (Pressure Sensitive Paint) technique. The film cooling performance of the compound angle fan-shaped holes was assessed at both design and off-design conditions. The object of this research is to change the concept that NGV leading edge film cooling experiment only needs the data at design condition. Through the comparative analysis of experimental results at different inlet flow angle, the influence of off-design condition on NGV leading edge and gill region film cooling could be illustrated at a reasonable level.

Scaling of Incidence Variations With Inlet Distortion for a Transonic Axial Compressor

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
D. J. Hill ◽  
J. J. Defoe
Keyword(s):  
Total Pressure ◽  
Incidence Angle ◽  
Computational Cost ◽  
Force Model ◽  
Flow Angle ◽  
Total Enthalpy ◽  
Transonic Compressor ◽  
Inlet Distortion ◽  
Scaling Relationships ◽  
The Impact

Abstract This paper numerically explores the manner in which blade row inlet incidence variation scales with various distortion patterns and intensities. The objectives are to (1) identify the most appropriate parameter whose circumferential variation can be used to assess scaling relationships of a transonic compressor and (2) use this parameter to evaluate two types of non-uniform inflow patterns, vertically stratified total pressure distortions and radially stratified total enthalpy and total pressure distortions. A body force model of the blade rows is employed to reduce computational cost; the approach has been shown to capture distortion transfer and to be able to predict upstream flow redistribution with inlet distortion. Diffusion factor is shown to be an inadequate proxy for streamline loss generation in non-uniform flow, leading to the choice of incidence angle variations as the metric for which we assess scaling relationships. Posteriori scaling of circumferential flow angle variation based on the maximum incidence excursion for varying distortion intensity yields an accurate method for prediction of the impact for other distortion intensities; linear regression of the maximum variation in incidence around the annulus as a function of distortion intensity had R2 > 0.97 for all spanwise locations examined in both the rotor and stator for both vertically and radially stratified distortions. However, changes to far upstream distortion shape yield highly non-linear incidence variation scaling; the results suggest that the pitchwise gradients of far upstream total pressure govern the degree of linearity for incidence variation scaling.

Aerodynamic Investigation of a Nozzle Clearance Effect on Radial Turbine Performance

2012 ◽  
Author(s):  
M. Roumeas ◽  
S. Cros
Keyword(s):  
Blade Angle ◽  
Axial Fan ◽  
Flow Angle ◽  
Turbine Performance ◽  
Radial Turbine ◽  
The One ◽  
Cooling Air ◽  
The Impact ◽  
Aerodynamic Investigation ◽  
Nozzle Blade

Liebherr Aerospace designs and develops cooling air systems, with notably axial fan and radial turbine or compressor. The development of new architectures (especially electrical system) now requires improving the turbine performances on the whole operating range. To reach that industrial request, a variable nozzle area can be used, performed by changing the nozzle blade angle for a given blade height. For the blades to be moveable, tip and hub clearances must be present (and thus modeled) in the nozzle. The impact of that clearance on the turbine performance, and moreover on the flow field, is studied here by 3D numerical way. The clearance mass flow leads to the development of a marginal vortex along the nozzle blade chord that tends to increase the total pressure loss in the nozzle on the one hand, and to modify the flow angle on the rotor inlet on the other hand. The vortex development induces an efficiency loss that must be taken into account during the design.

scholarly journals Experimentally Measured Effects of Incidence Angle on the Adiabatic and Overall Effectiveness of a Fully Cooled Turbine Airfoil With Shaped Showerhead Holes

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Kyle Chavez ◽  
Thomas N. Slavens ◽  
David Bogard
Keyword(s):  
Incidence Angle ◽  
Density Ratio ◽  
Leading Edge ◽  
Inlet Flow ◽  
Flow Angle ◽  
Stagnation Line ◽  
Film Cooling Effectiveness ◽  
Adiabatic Effectiveness ◽  
Inlet Conditions ◽  
Overall Effectiveness

Manufacturing and assembly variation can lead to shifts in the inlet flow incidence angles of a rotating turbine airfoil row. Understanding the sensitivity of the adiabatic film cooling effectiveness to a range of inlet conditions is necessary to verify the robustness of a cooling design. In order to investigate the effects of inlet flow incidence angles, adiabatic and overall effectiveness data were measured in a low speed linear cascade at 0 deg and 10 deg of the designed operating condition. Tests were completed at an inlet Reynolds number of Re = 120,000 and a turbulence intensity of Tu = 5% at the leading edge of the test article. Particle image velocimetry was used to verify the incident flow angle for each angle studied. The test section was first adjusted so that the pressure distribution and stagnation line of the airfoil matched those predicted by an aerodynamic computational fluid dynamics (CFD) model. IR thermography was then used to measure the adiabatic effectiveness levels of the fully cooled airfoil model with nine rows of shaped holes of varying construction and feed delivery. Measurements were taken over a range of blowing ratios and at a density ratio of DR = 1.23. This process was repeated for the two incidence angles measured, while the inlet pressure to the airfoil model was held constant for these incidence angle changes. Differences in laterally adiabatic effectiveness across the airfoil model were most evident in the showerhead, with changes as large as 0.2. The effect persisted most strongly at s/D = ±35 downstream of the stagnation row of holes, but was visible over the whole viewable area of 160 s/D. The effect was due to the stagnation line affecting the film at the showerhead row. Due to this effect, the showerhead was investigated in detail, including the effects of the stagnation line shift as well as the influence of the incidence angle on the overall effectiveness of the showerhead region. It was found that the stagnation line has the tendency to dramatically increase the near-hole adiabatic effectiveness levels when positioned within the breakout footprint of the hole. The effect persisted for the overall effectiveness study, since the hole spacing for this particular configuration was wide enough that the through hole convection was not completely dominant. This is the first study to present measured effectiveness values over both the pressure- and suction-side surfaces of a fully cooled airfoil for appreciably off-nominal incidence angles as well as examine adiabatic and overall effectiveness levels for a conical stagnation row of holes.

Uncertainty Quantification of Aero-Thermal Performance of a Blade Endwall Considering Slot Geometry Deviation and Mainstream Fluctuation

2021 ◽  
pp. 1-48
Author(s):  
Zhi Tao ◽  
Zhendong Guo ◽  
Liming Song ◽  
Jun Li
Keyword(s):  
Uncertainty Quantification ◽  
Thermal Performance ◽  
Gas Turbines ◽  
Incidence Angle ◽  
Uncertain Parameters ◽  
Inlet Flow ◽  
Flow Angle ◽  
Actual Performance ◽  
Film Cooling Effectiveness ◽  
Input Uncertainties

Abstract With the ever-increasing aerodynamic and thermal loads, the endwalls of modern gas turbines have become critical areas that are susceptible to manufacturing and operational uncertainties, making them highly prone to thermal failures. Therefore, it is of vital importance to quantify the impacts of input uncertainties on the aero-thermal performance of endwalls. Firstly, based on the Kriging surrogate, an efficient uncertainty quantification (UQ) method suitable for expensive CFD problems is proposed. Using this method, the impacts of slot geometry deviations (slot width, endwall misalignment) and mainstream condition fluctuations (turbulence intensity, inlet flow angle) on the aero-thermal performance of endwalls are quantified. Results show that the actual performance of endwalls has a high probability of deviating from its nominal value. The maximum deviations of aerodynamic loss, area-averaged film cooling effectiveness, and area-averaged Nusselt number reach 0.33%, 45%, and 5.0%, respectively. The critical regions that are most sensitive to the input uncertainties are also identified. Secondly, a global sensitivity analysis method is also performed to pick out the significant uncertain parameters and explore the relationship between input uncertainties and performance output. The inlet flow angle is proved to be the most significant parameter among the four input uncertain parameters. Besides, a positive incidence angle is found to be detrimental to both the aerodynamic performance and the thermal management of endwalls. At last, the influence mechanisms of the inlet flow angle on endwall aero-thermal performance are clarified by a fundamental analysis of flow and thermal fields.

A Contribution to the Study of Exit Flow Angle in Radial Turbines

1991 ◽  
Author(s):  
Edward A. Brizuela
Keyword(s):  
Experimental Data ◽  
Relative Motion ◽  
Centrifugal Forces ◽  
Hydraulic Radius ◽  
Flow Angle ◽  
Velocity Gradients ◽  
Radial Turbine ◽  
New Models ◽  
Mathematical Relationships ◽  
Radial Turbines

The emergence and evolution of relative whirling motions in the exducer region of an Inward Flow Radial Turbine is discussed. Existing models of relative motion are reviewed and expanded by consideration of the effect of centrifugal forces differences arising from velocity gradients. It is shown that the often observed phenomenon of outlet overturn/underturn is inherent to the use of straight-helix exducers. Explicit mathematical relationships between exit velocities and radius are not available. If, however, such relationships could be considered linear, it is shown that two new reference radii may be identified such that the net outlet properties can be measured or computed at these locations as lump parameters. These radii are different from the often used hydraulic radius. The new models and reference radii are verified using published experimental data.

A Direct Performance Comparison of Vaned and Vaneless Stators for Radial Turbines

2006 ◽  
Vol 129 (1) ◽  
pp. 53-61 ◽  
Author(s):  
S. W. T. Spence ◽  
R. S. E. Rosborough ◽  
D. Artt ◽  
G. McCullough
Keyword(s):  
Performance Comparison ◽  
Performance Model ◽  
Operating Conditions ◽  
One Dimensional ◽  
Turbine Performance ◽  
Radial Turbine ◽  
Surface Finishes ◽  
The Impact ◽  
Radial Turbines ◽  
Extensive Performance

An extensive performance investigation has been conducted on a radial turbine with three different vaneless volutes and three corresponding vaned stators. Previously published comparisons have been based on turbines with unmatched flow rates, meaning that the impact of stator losses was not isolated from rotor and exit losses. Each vaned stator configuration tested in this investigation matched the flow rate of the corresponding vaneless volute to within 1%. The volutes and the vaned stators were all machined in order to achieve high quality and comparable surface finishes. At all operating conditions, the vaneless volutes were shown to deliver a significant efficiency advantage over the vaned stators. However, the vaneless volute turbines did not demonstrate any greater tolerance for off-design operating conditions than the vaned stator configurations. Full performance data are presented for the six different turbine configurations tested and a one-dimensional turbine performance model is evaluated as a means of predicting and extrapolating turbine performance.

scholarly journals Turbine Design and Optimization for a Supercritical CO2 Cycle Using a Multifaceted Approach Based on Deep Neural Network

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7807
Author(s):  
Muhammad Saeed ◽  
Abdallah S. Berrouk ◽  
Burhani M. Burhani ◽  
Ahmed M. Alatyar ◽  
Yasser F. Al Wahedi
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Design Parameters ◽  
Speed Ratio ◽  
Inlet Flow ◽  
Flow Angle ◽  
Multifaceted Approach ◽  
Design And Optimization ◽  
Radial Turbine ◽  
Turbine Design

Turbine as a key power unit is vital to the novel supercritical carbon dioxide cycle (sCO2-BC). At the same time, the turbine design and optimization process for the sCO2-BC is complicated, and its relevant investigations are still absent in the literature due to the behavior of supercritical fluid in the vicinity of the critical point. In this regard, the current study entails a multifaceted approach for designing and optimizing a radial turbine system for an 8 MW sCO2 power cycle. Initially, a base design of the turbine is calculated utilizing an in-house radial turbine design and analysis code (RTDC), where sharp variations in the properties of CO2 are implemented by coupling the code with NIST’s Refprop. Later, 600 variants of the base geometry of the turbine are constructed by changing the selected turbine design geometric parameters, i.e., shroud ratio (rs4r3), hub ratio (rs4r3), speed ratio (νs) and inlet flow angle (α3) and are investigated numerically through 3D-RANS simulations. The generated CFD data is then used to train a deep neural network (DNN). Finally, the trained DNN model is employed as a fitting function in the multi-objective genetic algorithm (MOGA) to explore the optimized design parameters for the turbine’s rotor geometry. Moreover, the off-design performance of the optimized turbine geometry is computed and reported in the current study. Results suggest that the employed multifaceted approach reduces computational time and resources significantly and is required to completely understand the effects of various turbine design parameters on its performance and sizing. It is found that sCO2-turbine performance parameters are most sensitive to the design parameter speed ratio (νs), followed by inlet flow angle (α3), and are least receptive to shroud ratio (rs4r3). The proposed turbine design methodology based on the machine learning algorithm is effective and substantially reduces the computational cost of the design and optimization phase and can be beneficial to achieve realistic and efficient design to the turbine for sCO2-BC.

On the Effect of Volute Tongue Design on Radial Turbine Performance

2012 ◽  
Author(s):  
Jan F. Suhrmann ◽  
Dieter Peitsch ◽  
Marc Gugau ◽  
Tom Heuer
Keyword(s):  
Flow Field ◽  
Gas Turbines ◽  
Preliminary Design ◽  
Turbine Stage ◽  
Turbine Wheel ◽  
Inlet Flow ◽  
Flow Angle ◽  
Flow Parameters ◽  
Radial Turbine ◽  
The One

With an increasing need for gas turbines with rather low flow rates in many industrial applications, e.g. decentralized power generation, aircrafts or automotive turbochargers, the development of small size radial turbines becomes more and more important. A major step in the development of a radial turbine stage is the preliminary design, which is the definition of basic geometrical features and the calculation of general turbine flow parameters at the design point and within the operating range. These are mainly the rotational speed, the expansion ratio, the flow rate and in particular the expected turbine efficiency. In a radial turbine stage, the volute component delivers the flow to the rotor wheel and according to the geometrical form it defines major flow parameters like the mass flow parameter or the absolute rotor inlet flow angle. Amongst others, the way the flow enters the turbine wheel represents one of the most important loss generating factors. Thus, on the one hand an approach is necessary for the calculation of the optimum rotor inlet flow angle, in order to avoid dispensable losses due to secondary flow in the turbine wheel region. On the other hand, the volute tongue generates flow non-uniformity which has an effect on the overall circumferential averaged rotor inlet flow angle. Furthermore, the local flow pattern downstream of the volute tongue can generate suboptimal flow conditions for the turbine wheel. Hussain and Bhinder [1] measured the flow field at the outlet of a vaneless volute at different circumferential positions and detected a variation of the outlet angle of about Δα = 10°. The authors conclusion was, that the influence on the stage performance of flow non-uniformity generated by the volute could exceed the one of pressure losses through the volute. In this paper, the effect of different geometrical volute parameters on the flow condition especially at the turbine wheel inlet area is investigated. Experimental data of the influence of different volute tongue geometries on the flow field is difficult to generate. Hence, comprehensive numerical investigations are made using steady 3D-CFD calculations of the turbine volute as well as calculations of complete turbine stages including a turbine wheel geometry. Based on the numerical results, a design guideline is developed to estimate the influence of the geometric volute parameters on the flow and to raise the quality of the preliminary design process.

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