On Forced Vibration of Shrouded Turbine Blades

2003 ◽  
Author(s):  
J. Szwedowicz ◽  
W. Sextro ◽  
R. Visser ◽  
P. A. Masserey
Keyword(s):  
Forced Vibration ◽  
Close Agreement ◽  
Turbine Blades ◽  
Normal Vector ◽  
Blade Design ◽  
Air Jet ◽  
Numerical Predictions ◽  
Linear Behavior ◽  
Frictional Damping ◽  
Frictional Effects

Numerical predictions of the forced vibration of a disc assembly including frictional effects between the shrouds are presented concerning engineering needs for the blade design process. Assuming a tuned disc assembly, numerical static, free and then forced vibration analyses of a shrouded turbine blade measured in the spin pit are performed systematically. For the excitation forces of an air jet evaluated from the fairly linear behavior of the experimental blade resonance peaks, the reliability of the proposed approach is validated through the very close agreement of the computed and measured resonant peaks. These resonant peaks demonstrate either a fairly linear behavior or a non-linear one like the jump effect of blade resonance amplitudes, or elastic impacts between the shrouds. Also, the damping performance for different contact configurations between the shrouds is numerically analyzed. These numerical results indicate that the shrouds generate higher frictional damping for small angles (0–30 deg) between the circumferential direction and the normal vector to the contact surface.

Optimization of Supersonic Axial Turbine Blades Based on Surrogate Models

2020 ◽  
Author(s):  
Markus Waesker ◽  
Bjoern Buelten ◽  
Norman Kienzle ◽  
Christian Doetsch
Keyword(s):  
Reynolds Number ◽  
Turbine Blade ◽  
Surrogate Model ◽  
Cfd Simulation ◽  
Turbine Blades ◽  
Energy System ◽  
Design Parameters ◽  
Blade Design ◽  
Axial Turbine ◽  
Velocity Coefficient

Abstract Due to the transition of the energy system to more decentralized sector-coupled technologies, the demand on small, highly efficient and compact turbines is steadily growing. Therefore, supersonic impulse turbines have been subject of academic research for many years because of their compact and low-cost conditions. However, specific loss models for this type of turbine are still missing. In this paper, a CFD-simulation-based surrogate model for the velocity coefficient, unique incidence as well as outflow deviation of the blade, is introduced. This surrogate model forms the basis for an exemplary efficiency optimization of the “Colclough cascade”. In a first step, an automatic and robust blade design methodology for constant-channel blades based on the supersonic turbine blade design of Stratford and Sansome is shown. The blade flow is fully described by seven geometrical and three aerodynamic design parameters. After that, an automated numerical flow simulation (CFD) workflow for supersonic turbine blades is developed. The validation of the CFD setup with a published supersonic axial turbine blade (Colclough design) shows a high consistency in the shock waves, separation zones and boundary layers as well as velocity coefficients. A design of experiments (DOE) with latin hypercube sampling and 1300 sample points is calculated. This CFD data forms the basis for a highly accurate surrogate model of supersonic turbine blade flow suitable for Mach numbers between 1.1 and 1.6. The throat-based Reynolds number is varied between 1*104 and 4*105. Additionally, an optimization is introduced, based on the surrogate model for the Reynolds number and Mach number of Colclough and no degree of reaction (equal inlet and outlet static pressure). The velocity coefficient is improved by up to 3 %.

Hybrid Polymer Additive Manufacturing of a Darrieus Type Vertical Axis Wind Turbine Design to Improve Power Generation Efficiency

2016 ◽  
Author(s):  
Sourabh Deshpande ◽  
Nithin Rao ◽  
Nitin Pradhan ◽  
John L. Irwin
Keyword(s):  
Power Generation ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Blade Design ◽  
Vertical Axis Wind Turbine ◽  
Wind Turbine Blades ◽  
3D Printed

Utilizing the advantages of additive manufacturing methods, redesigning, building and testing of an existing integral Savonius / Darrieus “Lenz2 Wing” style vertical axis wind turbine is predicted to improve power generation efficiency. The current wind turbine blades and supports made from aluminum plate and sheet are limiting the power generation due to the overall weight. The new design is predicted to increase power generation when compared to the current design due to the lightweight spiral Darrieus shaped hollow blade made possible by 3D printing, along with an internal Savonius blade made from aluminum sheet and traditional manufacturing techniques. The design constraints include 3D printing the turbine blades in a 0.4 × 0.4 × 0.3 m work envelope while using a Stratasys Fortus 400mc and thus the wind turbine blades are split into multiple parts with dovetail joint features, when bonded together result in a 1.2 m tall working prototype. Appropriate allowance in the mating dovetail joints are considered to facilitate the fit and bonding, as well as angle, size and placement of the dovetail to maximize strength. The spiral shape and Darrieus style cross section of the blade that provides the required lift enabling it to rotate from the static condition are oriented laterally for 3D printing to maximize strength. The bonding of the dovetail joints is carried out effectively using an acetone solution dip. The auxiliary components of the wind turbine which include the center support pole, top and bottom support, and center Savonius blades are manufactured using lightweight aluminum. Design features are included in the 3D printed blade parts so that they can be assembled with the aluminum parts in bolted connections. Analysis of the 3D CAD models show that the hybrid aluminum and hollow 3D printed blade construction provides a 50% cost savings over a 3D printed fully solid blade design while minimizing weight and maximizing the strength where necessary. Analysis of the redesign includes a detailed weight comparison, structural strength and the cost of production. Results include linear static finite element analysis for the strength in dovetail joint bonding and the aluminum to 3D printed connections. Additional data reported are the time frame for the design and manufacturing of the system, budget, and an operational analysis of the wind turbine with concern for safety. Results are analyzed to determine the advantages in utilizing a hybrid additive manufacturing and aluminum construction for producing a more efficient vertical axis wind turbine. Techniques used in the production of this type of wind turbine blade are planned to be utilized in similar applications such as a lightweight hovercraft propeller blade design to be tested in future research projects.

An Experimental Study of the Enhancement of Air-Cooling Limits for Telecom/Datacom Heat Sink Applications Using an Impinging Air Jet

2005 ◽  
Vol 128 (2) ◽  
pp. 166-171 ◽  
Author(s):  
Eric Sansoucy ◽  
Patrick H. Oosthuizen ◽  
Gamal Refai-Ahmed
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Heat Sink ◽  
Target Surface ◽  
Junction Temperature ◽  
Air Cooling ◽  
Nusselt Numbers ◽  
Air Jet ◽  
Numerical Predictions ◽  
Nozzle Plate

An experimental study was conducted to investigate the heat transfer from a parallel flat plate heat sink under a turbulent impinging air jet. A horizontal nozzle plate confined the target surface. The jet was discharged from a sharp-edged nozzle in the nozzle plate. Average Nusselt numbers are reported for Pr=0.7, 5000⩽Re⩽30,000, L∕d=2.5, and 0.833 at H∕d=3 where L, H, and d define the length of the square heat source, nozzle-to-target spacing, and nozzle diameter, respectively. Tests were also conducted for an impinging flow over a flat plate, flush with the top surface of the target plate. The average Nusselt numbers from the heat sink were compared to those for a flat plate to determine the overall performance of the heat sink in a confined impingement arrangement. The experimental results were compared with the numerical predictions obtained in an earlier study. Although the average Nusselt numbers obtained from numerical simulations differed from the experimental measurements by 18%, the disagreement is much less significant when related to the junction temperature. Under typical conditions, it was shown that such discrepancy in the Nusselt number lead to an error of 6% in the prediction of the junction temperature of the device.

Computation of flow and heat transfer through channels with periodic dimple/protrusion walls using low-Reynolds number turbulence models

2019 ◽  
Vol 29 (3) ◽  
pp. 1178-1207 ◽  
Author(s):  
Mohammad Fazli ◽  
Mehrdad Raisee
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Correction Term ◽  
Turbine Blades ◽  
Turbulence Models ◽  
Internal Cooling ◽  
Recirculation Bubble ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Numerical Predictions

PurposeThis paper aims to predict turbulent flow and heat transfer through different channels with periodic dimple/protrusion walls. More specifically, the performance of various low-Rek-ε turbulence models in prediction of local heat transfer coefficient is evaluated.Design/methodology/approachThree low-Re numberk-εturbulence models (the zonalk-ε, the lineark-εand the nonlineark-ε) are used. Computations are performed for three geometries, namely, a channel with a single dimpled wall, a channel with double dimpled walls and a channel with a single dimple/protrusion wall. The predictions are obtained using an in house finite volume code.FindingsThe numerical predictions indicate that the nonlineark-εmodel predicts a larger recirculation bubble inside the dimple with stronger impingement and upwash flow than the zonal and lineark-εmodels. The heat transfer results show that the zonalk-εmodel returns weak thermal predictions in all test cases in comparison to other turbulence models. Use of the lineark-εmodel leads to improvement in heat transfer predictions inside the dimples and their back rim. However, the most accurate thermal predictions are obtained via the nonlineark-εmodel. As expected, the replacement of the algebraic length-scale correction term with the differential version improves the heat transfer predictions of both linear and nonlineark-εmodels.Originality/valueThe most reliable turbulence model of the current study (i.e. nonlineark-εmodel) may be used for design and optimization of various thermal systems using dimples for heat transfer enhancement (e.g. heat exchangers and internal cooling system of gas turbine blades).

scholarly journals Non-Hydrostatic Modeling of Waves Generated by Landslides with Different Mobility

2019 ◽  
Vol 7 (8) ◽  
pp. 266 ◽  
Author(s):  
Ryan P. Mulligan ◽  
W. Andy Take ◽  
Gemma K. Bullard
Keyword(s):  
Momentum Flux ◽  
Water Surface ◽  
Laboratory Experiments ◽  
Close Agreement ◽  
Short Communication ◽  
High Mobility ◽  
Numerical Predictions ◽  
New Research ◽  
The Waves ◽  
Transfer Momentum

Tsunamis are generated when landslides transfer momentum to water, and these waves are major hazards in the mountainous coastal areas of lakes, reservoir, and fjords. In this study, the influence of slide mobility on wave generation is investigated using new: (i) experimental observations; (ii) theoretical relationships; and (iii) non-hydrostatic numerical predictions of the water surface and flow velocity evolution. This is accomplished by comparing landslides with low and high mobility and computing the momentum flux from landslides to water based on data collected in laboratory experiments. These slides have different materials, different impact velocities, different submarine runout distances, and generate very different waves. The waves evolve differently along the length of the waves’ flume, and the experimental results are in close agreement with high-resolution phase-resolving simulations. In this short communication, we describe new research on landslide generated waves conducted at Queen’s University, Canada, and presented at Coastlab18 in Santander, Spain.

Accelerated 3D Aerodynamic Optimization of Gas Turbine Blades

2014 ◽  
Author(s):  
Philipp Amtsfeld ◽  
Michael Lockan ◽  
Dieter Bestle ◽  
Marcus Meyer
Keyword(s):  
Turbine Blades ◽  
Three Dimensional ◽  
Optimization Process ◽  
Design Parameters ◽  
Blade Design ◽  
Aerodynamic Optimization ◽  
Multi Stage ◽  
Design Variables ◽  
Real Flow ◽  
Blade Model

State-of-the-art aerodynamic blade design processes mainly consist of two phases: optimal design of 2D blade sections and then stacking them optimally along a three-dimensional stacking line. Such a quasi-3D approach, however, misses the potential of finding optimal blade designs especially in the presence of strong 3D flow effects. Therefore, in this paper a blade optimization process is demonstrated which uses an integral 3D blade model and 3D CFD analysis to account for three-dimensional flow features. Special emphasis is put on shortening design iterations and reducing design costs in order to obtain a rapid automatic optimization process for fully 3D aerodynamic turbine blade design which can be applied in an early design phase already. The three-dimensional parametric blade model is determined by up to 80 design variables. At first, the most important design parameters are chosen based on a non-linear sensitivity analysis. The objective of the subsequent optimization process is to maximize isentropic efficiency while fulfilling a minimal set of constraints. The CFD model contains both important geometric features like tip gaps and fillets, and cooling and leakage flows to sufficiently represent real flow conditions. Two acceleration strategies are used to cut down the turn-around time from weeks to days. Firstly, the aerodynamic multi-stage design evaluation is significantly accelerated with a GPU-based RANS solver running on a multi-GPU workstation. Secondly, a response surface method is used to reduce the number of expensive function evaluations during the optimization process. The feasibility is demonstrated by an application to a blade which is a part of a research rig similar to the high pressure turbine of a small civil jet engine. The proposed approach enables an automatic aerodynamic design of this 3D blade on a single workstation within few days.

Wind Turbine Blade Design and Analysis With Tubercle Technology

2012 ◽  
Author(s):  
Sourabh Kumar ◽  
R. S. Amano
Keyword(s):  
Wind Turbine ◽  
Flow Pattern ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Cad Model ◽  
Blade Design ◽  
Cfd Analysis ◽  
Straight Blade ◽  
Turbine Blade Design ◽  
Insight Into

The objective of this project is to construct a CAD model for tubercle wind turbine. Once the model is developed a complete CFD analysis of the flow pattern around the wind turbine will be carried out. The main objective of the study is to analyze and compare the performance of the tubercle wind turbine with the usual wind turbine. The power developed by both the turbine blades can be compared to support the use of tubercle. The tubercles are very effective for increasing the lift without stalling. The main objective of this project is to study the aerodynamic advantages of tubercle turbine blade. The effort will be to compare the obtained results with the straight blade of the same airfoil. This will provide insight into the advantages of using the tubercle blade. This technology being new the study is done numerically to study the overall effect of the tubercle.

Seagull in Wind Turbine Airfoil Blade Design Application Bionic

2013 ◽  
Vol 380-384 ◽  
pp. 4336-4339
Author(s):  
Hua Xin ◽  
Chun Hua Zhang ◽  
Qing Guo Zhang ◽  
Ping Wang
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Simulation Analysis ◽  
Turbine Blades ◽  
Clean Energy ◽  
Aerodynamic Performance ◽  
Blade Design ◽  
Wind Turbine Blades ◽  
Bionic Blade ◽  
Turbine Blade Design

Wind energy is an inexhaustible, an inexhaustible source of renewable and clean energy. Present due to the energy crisis and environmental protection and other issues, the use of wind more and more world attention. The wind turbine is the best form of wind energy conversion. Wind turbine wind turbine blades to capture wind energy is the core component of the blade in a natural environment to run directly in contact with air, with seagulls wings generate lift conditions are similar, so the gull wings airfoil and excellent conformation, with wind turbine blade design designed by combining the bionic blades. Through numerical simulation analysis found bionic blade aerodynamic performance than the standard blade aerodynamic performance has improved.

An Optimum Aero-Design Process of Turbine Blades

2002 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Design Process ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Optimization Procedure ◽  
Compressor Blade ◽  
Advanced Technology ◽  
Test Case ◽  
Blade Design

With the development of the advanced technology, the combustion temperature is raised for increased efficiencies. At the same time, the turbine and compressor pressure ratio and the mass flow rate rise; thus causing turbine and compressor blades turning and blade lengths increase. Moreover, the high efficiency requirements had made the turbine and compressor blade design difficult. A turbine airfoil has been custom designed for many years, but an optimization for the section design in a three-dimensional consideration is still a challenge. For a compressor blade design, standard section cannot meet the modern compressor requirements. Modern compressor design has not only needs a custom designed section according to flow situation, but also needs three-dimensional optimizations. Therefore, a good blade design process is critical to the turbines and compressors. A blade design of the turbomachines is one of the important steps for a good turbomachine design. A blade design process not only directly influences the overall machine efficiency but also dramatically impact the design time and cost. In this study, a blade design and optimization procedure was proposed for both turbine and compressor blade design. A compressor blade design was used as a test case. It was shown that the current design process had more advantages than conventional design methodology.

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