scholarly journals Assessment of current rotor design comparison practices based on high-fidelity CFD methods

2020 ◽  
Vol 124 (1275) ◽  
pp. 731-766
Author(s):  
T. Fitzgibbon ◽  
M. Woodgate ◽  
G. Barakos
Keyword(s):  
High Speed ◽  
Performance Metrics ◽  
Rotor Blades ◽  
High Fidelity ◽  
Rotor Design ◽  
Performance Predictions ◽  
Accurate Performance ◽  
Cfd Method ◽  
Drag Ratio ◽  
Design Comparison

ABSTRACTThis paper provides an assessment of current rotor design comparison practices. First, the employed CFD method is validated for a number of rotor designs and is shown to achieve accurate performance predictions in hover and high-speed forward flight. Based on CFD results, a detailed investigation is performed in terms of comparing different rotor designs. The CFD analysis highlighted the need of high fidelity methods due to the subtle aerodynamics involved in advanced planforms. Nevertheless, the paper suggests that the correct basis for comparison in terms of performance metrics must be used to inform decisions about the suitability of the rotor blades designs for specific applications. In particular, when comparing blades of advanced planforms, direct torque and thrust comparisons are better than the commonly used lift to drag ratio and figure of merit.

Computational aeroelastic analysis of slowed rotors at high advance ratios

2014 ◽  
Vol 118 (1201) ◽  
pp. 297-313 ◽  
Author(s):  
J. de Montaudouin ◽  
N. Reveles ◽  
M. J. Smith
Keyword(s):  
High Speed ◽  
Rotor Blades ◽  
Vortex Interaction ◽  
Blade Loading ◽  
Blade Vortex Interaction ◽  
Aeroelastic Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Advance Ratio ◽  
Cfd Method ◽  
Model Rotor

Abstract The aerodynamic and aeroelastic behaviour of a rotor become more complex as advance ratios increase to achieve high-speed forward fight. As the rotor blades encounter large regions of cross and reverse flows during each revolution, strong variations in the local Mach regime are encountered, inducing complex elastic blade deformations. In addition, the wake system may remain in the vicinity of the rotor, adding complexity to the blade loading. The aeroelastic behaviour of a model rotor with advance ratios ranging from 0·5 to 2·0 has been evaluated with aerodynamics provided via a computational fluid dynamics (CFD) method. Significant radial blade-vortex interaction can occur at a high advance ratio; the advance ratio at which this occurs is dependent on the rotor configuration. This condition is accompanied by high vibratory loads, peak negative torsion, and peak torsion and in-plane loads. The high vibratory loading increases the sensitivity of the trim model, so that at some high advance ratios the vibratory loads must be filtered to achieve a trimmed state.

scholarly journals Getting High: High Fidelity Simulation of High Granularity Calorimeters with High Speed

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Erik Buhmann ◽  
Sascha Diefenbacher ◽  
Engin Eren ◽  
Frank Gaede ◽  
Gregor Kasieczka ◽  
...  
Keyword(s):  
Particle Physics ◽  
High Speed ◽  
Deep Neural Networks ◽  
High Fidelity ◽  
High Fidelity Simulation ◽  
Physical Processes ◽  
Electromagnetic Showers ◽  
Information Bottleneck ◽  
First Time ◽  
Processing Network

AbstractAccurate simulation of physical processes is crucial for the success of modern particle physics. However, simulating the development and interaction of particle showers with calorimeter detectors is a time consuming process and drives the computing needs of large experiments at the LHC and future colliders. Recently, generative machine learning models based on deep neural networks have shown promise in speeding up this task by several orders of magnitude. We investigate the use of a new architecture—the Bounded Information Bottleneck Autoencoder—for modelling electromagnetic showers in the central region of the Silicon-Tungsten calorimeter of the proposed International Large Detector. Combined with a novel second post-processing network, this approach achieves an accurate simulation of differential distributions including for the first time the shape of the minimum-ionizing-particle peak compared to a full Geant4 simulation for a high-granularity calorimeter with 27k simulated channels. The results are validated by comparing to established architectures. Our results further strengthen the case of using generative networks for fast simulation and demonstrate that physically relevant differential distributions can be described with high accuracy.

Influence of Main Swirler Vane Angle on the Ignition Performance of TeLESS-II Combustor

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Bo Wang ◽  
Chi Zhang ◽  
Yuzhen Lin ◽  
Xin Hui ◽  
Jibao Li
Keyword(s):  
High Speed ◽  
Inlet Temperature ◽  
Main Stage ◽  
Ignition Process ◽  
High Speed Camera ◽  
Fuel Distribution ◽  
Fuel Droplets ◽  
Planar Laser ◽  
Cfd Method ◽  
Vane Angle

In order to balance the low emission and wide stabilization for lean premixed prevaporized (LPP) combustion, the centrally staged layout is preferred in advanced aero-engine combustors. However, compared with the conventional combustor, it is more difficult for the centrally staged combustor to light up as the main stage air layer will prevent the pilot fuel droplets arriving at igniter tip. The goal of the present paper is to study the effect of the main stage air on the ignition of the centrally staged combustor. Two cases of the main swirler vane angle of the TeLESS-II combustor, 20 deg and 30 deg are researched. The ignition results at room inlet temperature and pressure show that the ignition performance of the 30 deg vane angle case is better than that of the 20 deg vane angle case. High-speed camera, planar laser induced fluorescence (PLIF), and computational fluids dynamics (CFD) are used to better understand the ignition results. The high-speed camera has recorded the ignition process, indicated that an initial kernel forms just adjacent the liner wall after the igniter is turned on, the kernel propagates along the radial direction to the combustor center and begins to grow into a big flame, and then it spreads to the exit of the pilot stage, and eventually stabilizes the flame. CFD of the cold flow field coupled with spray field is conducted. A verification of the CFD method has been applied with PLIF measurement, and the simulation results can qualitatively represent the experimental data in terms of fuel distribution. The CFD results show that the radial dimensions of the primary recirculation zone of the two cases are very similar, and the dominant cause of the different ignition results is the vapor distribution of the fuel. The concentration of kerosene vapor of the 30 deg vane angle case is much larger than that of the 20 deg vane angle case close to the igniter tip and along the propagation route of the kernel, therefore, the 30 deg vane angle case has a better ignition performance. For the consideration of the ignition performance, a larger main swirler vane angle of 30 deg is suggested for the better fuel distribution when designing a centrally staged combustor.

scholarly journals Novel rotor design for high-speed flux reversal motor

2020 ◽  
Vol 6 ◽  
pp. 1544-1549
Author(s):  
Vladimir Dmitrievskii ◽  
Vladimir Prakht ◽  
Vadim Kazakbaev
Keyword(s):  
High Speed ◽  
Flux Reversal ◽  
Rotor Design

High-Fidelity Simulations of a High-Pressure Turbine Stage: Effects of Reynolds Number and Inlet Turbulence

2021 ◽  
Author(s):  
Yaomin Zhao ◽  
Richard D. Sandberg
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Suction Side ◽  
Rotor Blades ◽  
High Fidelity ◽  
Mean Flow ◽  
High Pressure Turbine ◽  
Flow Shear ◽  
Phase Lock ◽  
The Mean

Abstract We present the first wall-resolved high-fidelity simulations of high-pressure turbine (HPT) stages at engine-relevant conditions. A series of cases have been performed to investigate the effects of varying Reynolds numbers and inlet turbulence on the aerothermal behavior of the stage. While all of the cases have similar mean pressure distribution, the cases with higher Reynolds number show larger amplitude wall shear stress and enhanced heat fluxes around the vane and rotor blades. Moreover, higher-amplitude turbulence fluctuations at the inlet enhance heat transfer on the pressure-side and induce early transition on the suction-side of the vane, although the rotor blade boundary layers are not significantly affected. In addition to the time-averaged results, phase-lock averaged statistics are also collected to characterize the evolution of the stator wakes in the rotor passages. It is shown that the stretching and deformation of the stator wakes is dominated by the mean flow shear, and their interactions with the rotor blades can significantly intensify the heat transfer on the suction side. For the first time, the recently proposed entropy analysis has been applied to phase-lock averaged flow fields, which enables a quantitative characterization of the different mechanisms responsible for the unsteady losses of the stages. The results indicate that the losses related to the evolution of the stator wakes is mainly caused by the turbulence production, i.e. the direct interaction between the wake fluctuations and the mean flow shear through the rotor passages.

scholarly journals Aeromechanical Analysis of a Complete Wind Turbine Using Nonlinear Frequency Domain Solution Method

2020 ◽  
Author(s):  
Shine Win Naung ◽  
Mohammad Rahmati ◽  
Hamed Farokhi
Keyword(s):  
Wind Turbine ◽  
Frequency Domain ◽  
Solution Method ◽  
Computational Cost ◽  
Turbine Rotor ◽  
Forced Response ◽  
High Fidelity ◽  
Nonlinear Frequency ◽  
Cfd Method ◽  
Turbine Model

Abstract The high-fidelity computational fluid dynamics (CFD) simulations of a complete wind turbine model usually require significant computational resources. It will require much more resources if the fluid-structure interactions between the blade and the flow are considered, and it has been the major challenge in the industry. The aeromechanical analysis of a complete wind turbine model using a high-fidelity CFD method is discussed in this paper. The distinctiveness of this paper is the application of the nonlinear frequency domain solution method to analyse the forced response and flutter instability of the blade as well as to investigate the unsteady flow field across the wind turbine rotor and the tower. This method also enables the aeromechanical simulations of wind turbines for various inter blade phase angles in a combination with a phase shift solution method. Extensive validations of the nonlinear frequency domain solution method against the conventional time domain solution method reveal that the proposed frequency domain solution method can reduce the computational cost by one to two orders of magnitude.

scholarly journals Enhancement of WiMAX networks using OPNET modeler platform

2021 ◽  
Vol 23 (3) ◽  
pp. 1510
Author(s):  
Noor Nateq Alfaisaly ◽  
Suhad Qasim Naeem ◽  
Azhar Hussein Neama
Keyword(s):  
High Speed ◽  
Network Performance ◽  
Performance Metrics ◽  
Channel Model ◽  
Low Cost ◽  
Base Station ◽  
Multipath Channel ◽  
Coverage Area ◽  
Wimax Networks ◽  
Better Than

Worldwide interoperability microwave access (WiMAX) is an 802.16 wireless standard that delivers high speed, provides a data rate of 100 Mbps and a coverage area of 50 km. Voice over internet protocol (VoIP) is flexible and offers low-cost telephony for clients over IP. However, there are still many challenges that must be addressed to provide a stable and good quality voice connection over the internet. The performance of various parameters such as multipath channel model and bandwidth over the Star trajectoryWiMAX network were evaluated under a scenario consisting of four cells. Each cell contains one mobile and one base station. Network performance metrics such as throughput and MOS were used to evaluate the best performance of VoIP codecs. Performance was analyzed via OPNET program14.5. The result use of multipath channel model (disable) was better than using the model (ITU pedestrian A). The value of the throughput at 15 dB was approximately 1600 packet/sec, and at -1 dB was its value 1300 packet/se. According to data, the Multipath channel model of the disable type the value of the MOS was better than the ITU Pedestrian A type.

CFD Analysis of a Water Flume Design for Testing Marine and Hydrokinetics Energy Converters

2018 ◽  
Author(s):  
Akshith Subramanian ◽  
Navid Goudarzi
Keyword(s):  
Test Section ◽  
Lower Cost ◽  
Performance Metrics ◽  
Experimental Testing ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Design Parameters ◽  
Energy Technologies ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

Marine and hydrokinetic (MHK) energy resources with advantages such as predictability and less variability compared to other forms of renewable energies, have been drawing more interest in recent years. One important phase before commercialization of new MHK technologies is to conduct experimental testing and evaluate their performance in a real environment. In this work, a numerical computational fluid dynamics (CFD) method is used to study the fluid flow behavior within a designed water flume for MHK energy technologies. The water flume design parameters were given by the team collaborators at National Renewable Energy Laboratory (NREL) and Colorado School of Mines. The results from this simulation showed the flow characteristics within the test-section of the proposed water flume design. These results can be used for the follow on phases of this research that includes testing scaled MHK prototypes at different flow rates as well as optimizing either the water flume design to obtain more realistic flow characteristics within the test section or the MHK devices to obtain higher performance metrics at lower cost.

A High Fidelity Roll Dependent Aerodynamic Model for a Long Range, High Speed Missile

2022 ◽  
Author(s):  
Bradley T. Burchett ◽  
Justin L. Paul ◽  
Joseph D. Vasile ◽  
Joshua Bryson
Keyword(s):  
Long Range ◽  
High Speed ◽  
High Fidelity ◽  
Aerodynamic Model
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