scholarly journals CNN-Based Flow Control Device Modelling On Aerodynamic Airfoils

2021 ◽  
Author(s):  
Koldo Portal-Porras ◽  
Unai Fernandez-Gamiz ◽  
Ekaitz Zulueta ◽  
Alejandro Ballesteros-Coll ◽  
Asier Zulueta
Keyword(s):  
Flow Control ◽  
Flow Characteristics ◽  
Control Device ◽  
Computational Time ◽  
Cfd Simulations ◽  
Turbine Performance ◽  
Flow Control Devices ◽  
Flow Control Device ◽  
Computational Fluid Dynamics Cfd ◽  
Control Devices

Abstract Wind energy has become an important source of electricity generation, with the aim of achieving a cleaner and more sustainable energy model. However, wind turbine performance improvement is required to compete with conventional energy resources. To achieve this improvement, flow control devices are implemented on airfoils. Computational Fluid Dynamics (CFD) simulations are the most popular method for analyzing this kind of devices, but in recent years, with the growth of Artificial Intelligence, predicting flow characteristics using neural networks is becoming increasingly popular. In this work, 158 different CFD simulations of a DU91W(2)250 airfoil are conducted, with two different flow control devices, rotating microtabs and Gurney flaps, added on its Trailing Edge (TE). These flow control devices are implemented by using the cell-set meshing technique. These simulations are used to train and test a Convolutional Neural Network (CNN) for velocity and pressure field prediction and another CNN for aerodynamic coefficient prediction. The results show that the proposed CNN for field prediction is able to accurately predict the main characteristics of the flow around the flow control device, showing very slight errors. Regarding the aerodynamic coefficients, the proposed CNN is also capable to predict them reliably, being able to properly predict both the trend and the values. In comparison with CFD simulations, the use of the CNNs reduces the computational time in four orders of magnitude.

The Development of Active Flow Control Devices From Shape Memory Alloys for the Convective Cooling of Heated Surfaces

2008 ◽  
Author(s):  
Mohd S. Aris ◽  
Ieuan Owen ◽  
Chris J. Sutcliffe
Keyword(s):  
Heat Transfer ◽  
Flow Control ◽  
Heated Surface ◽  
Active Flow Control ◽  
Control Device ◽  
Flow Control Devices ◽  
Flow Control Device ◽  
Control Devices ◽  
Channel Configuration ◽  
Active Flow

This paper is concerned with the convective heat transfer of heated surfaces through the use of active flow control devices. An investigation has been carried out into the use of two flow control design configurations manufactured from Shape Memory Alloys (SMAs) which are activated at specified temperatures. In this design, a high surface temperature would activate rectangular flaps to change shape and protrude at a 45° angle of attack. This protrusion would generate longitudinal vortices and at the same time allow air to flow into cooling channels underneath the flaps, cooling a heated surface downstream of the flow control device. One- and two-channel flow control configurations were explored in this work. The flow control device was made from pre-alloyed powders of SMA material in a rapid prototyping process known as Selective Laser Melting (SLM). It was tested for its heat transfer enhancement in an open test section wind tunnel supplied with low velocity air flow. Infrared thermography was used to evaluate the surface temperatures of the downstream heated surface. Promising results were obtained for the flow control design when the heated surface temperatures were varied from 20 °C to 85 °C. In the one-channel configuration, the flow control device in its activated shape increased heat transfer to a maximum of 50% compared to its deactivated shape. The activated flow control device in the two-channel configuration experienced a heat transfer enhancement of up to 90% compared to when it is deactivated.

Optimizing of Flow Control Devices in a Single Strand Continuous Casting Tundish

2011 ◽  
Vol 284-286 ◽  
pp. 1209-1215 ◽  
Author(s):  
Lei Lei Zhang ◽  
Deng Fu Chen ◽  
Qiang Liu ◽  
Min Zhang ◽  
Xin Xie ◽  
...  
Keyword(s):  
Flow Field ◽  
Continuous Casting ◽  
Flow Control ◽  
Control Device ◽  
Flow Control Devices ◽  
Flow Control Device ◽  
Continuous Casting Tundish ◽  
Control Devices ◽  
Water Simulation ◽  
Orthogonal Optimization

Flow control devices (weir and dam) in a continuous casting tundish are very important to the flow field, which influences the temperature uniform and the inclusion floating. In this work, the weir and dam were firstly optimized through numerical simulation and water simulation synthetically by orthogonal optimization tests. And the optimal parameters showed that the distance from upper weir to inlet was 1000 mm, the distance of upper weir to tundish bottom was 150 mm, the distance from upper weir to dam was 600 mm, and the height of the dam was 320 mm. Then the effect of different arrangement holes on the dam was discussed through RTD curve and velocity field under the optimum flow control device. And it revealed that the hole influenced the flow pattern in that area obviously, a dam with two holes could get a better flow field.

scholarly journals Prediction of flow-control devices' noise with modified acoustic perturbation equations

2020 ◽  
Vol 22 (3) ◽  
pp. 619-627
Author(s):  
Luca Fenini ◽  
Stefano Malavasi
Keyword(s):  
Flow Control ◽  
Fluid Dynamic ◽  
International Standards ◽  
The Other ◽  
Computational Time ◽  
Noise Prediction ◽  
Acoustic Perturbation ◽  
Flow Control Devices ◽  
Control Devices ◽  
Perturbation Equations

Abstract Fluid-dynamic noise emissions produced by flow-control devices inside ducts are a concerning issue for valve manufacturers and pipeline management. This work proposes a modified formulation of Acoustic Perturbation Equations (APE) that is applicable to industrial frameworks where the interest is addressed to noise prediction according to international standards. This formulation is derived from a literature APE system removing two terms allowing for a computational time reduction of about 20%. The physical contribution of the removed terms is discussed according to the literature. The modified APE are applied to the prediction of the noise emitted by an orifice. The reliability of the new APE system is evaluated by comparing the Sound Pressure Level (SPL) and the acoustic pressure with the ones returned by LES and literature APE. The new formulation agrees with the other methods far from the orifice: moving over nine diameters downstream of the trailing edge, the SPL is in accordance with the other models. Since international standards characterize control devices with the noise measured 1 m downstream of them, the modified APE formulation provides reliable and faster noise prediction for those devices with outlet diameter, d, such that 9d < 1 m.

scholarly journals Design, Simulation, and Experiment of an LTCC-Based Xenon Micro Flow Control Device for an Electric Propulsion System

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 862 ◽  
Author(s):  
Chang-Bin Guan ◽  
Yan Shen ◽  
Zhao-Pu Yao ◽  
Zhao-Li Wang ◽  
Mei-Jie Zhang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Control ◽  
Electric Propulsion ◽  
Flow Characteristics ◽  
Control Device ◽  
Microfluidic Channels ◽  
Optimized Design ◽  
Element Analysis ◽  
Flow Control Device ◽  
Micro Flow

A xenon micro flow control device (XMFCD) is the key component of a xenon feeding system, which controls the required micro flow xenon (µg/s–mg/s) to electric thrusters. Traditional XMFCDs usually have large volume and weight in order to achieve ultra-high fluid resistance and have a long producing cycle and high processing cost. This paper proposes a miniaturized, easy-processing, and inexpensive XMFCD, which is fabricated by low-temperature co-fired ceramic (LTCC) technology. The design of the proposed XMFCD based on complex three-dimensional (3D) microfluidic channels is described, and its fabrication process based on LTCC is illustrated. The microfluidic channels of the fabricated single (9 mm diameter and 1.4 mm thickness) and dual (9 mm diameter and 2.4 mm thickness) XMFCDs were both checked by X-ray, which proved the LTCC method’s feasibility. A mathematical model of flow characteristics is established with the help of finite element analysis, and the model is validated by the experimental results of the single and dual XMFCDs. Based on the mathematical model, the influence of the structure parameters (diameter of orifice and width of the groove) on flow characteristics is investigated, which can guide the optimized design of the proposed XMFCD.

Investigation of a Passive Flow Control Device in an S-Duct Inlet at High Subsonic Flow

2021 ◽  
Author(s):  
Courtney Rider ◽  
Asad Asghar ◽  
William D. E. Allan ◽  
Grant Ingram ◽  
Robert Stowe ◽  
...  
Keyword(s):  
Flow Control ◽  
Control Strategy ◽  
Total Pressure ◽  
Subsonic Flow ◽  
Control Device ◽  
Test Rig ◽  
Flow Distortion ◽  
Cfd Simulations ◽  
Flow Control Device ◽  
High Subsonic Flow

Abstract This paper reports the investigation of a flow control strategy for an S-duct diffusers. The method incorporates stream-wise tubercles, and aims to enhance the performance of S-duct inlets by reducing the size and intensity of separated flow. These devices, bioinspired from humpback whale flippers’ leading edge protuberances, have been shown to be effective in increasing post-stall coefficients of lift of airfoils. In S-duct diffusers, the presence of convex curvature next to the separated region provides an ideal location for the installation of a tubercle-like device. The flow control effectiveness was evaluated by test-rig measurements and computational fluid dynamics (CFD) simulations of the flow in an S-duct at high subsonic flow conditions (Ma = 0.80). The S-ducts were rapid prototyped in plastic using 3D printing. Static surface pressure along the length and total pressure at the exit revealed pressure recovery, total pressure loss, swirl, and the nature of flow distortion at the S-duct exit. CFD simulations used ANSYS FLUENT with a RANS solver closed with the RKE turbulence model. The CFD simulation compared well with the test-rig data and provided useful information on flow mechanism and for understanding flow features. The performance of the baseline and variant with the flow control device was compared and flow control strategy was evaluated.

scholarly journals The flow past a flatback airfoil with flow control devices: Benchmarking numerical simulations against wind tunnel data

2020 ◽  
Author(s):  
George Papadakis ◽  
Marinos Manolesos
Keyword(s):  
Wind Tunnel ◽  
Flow Control ◽  
Control Device ◽  
Root Region ◽  
Flow Past ◽  
Flow Control Devices ◽  
Control Devices ◽  
Rans Simulations ◽  
Experimental Findings ◽  
Flatback Airfoil

Abstract. As wind turbines grow larger, the use of flatback airfoils has become standard practice for the root region of the blades. Flatback profiles provide higher lift and reduced sensitivity to soiling at significantly higher drag values. A number of flow control devices has been proposed to improve the performance of flatback profiles. In the present study, the flow past a flatback airfoil at a chord Reynolds number of 1.5 × 106 with and without trailing edge flow control devices is considered. Two different numerical approaches are applied, Unsteady Reynolds Averaged Navier Stokes (RANS) simulations and Detached Eddy Simulations (DES). The computational predictions are compared to wind tunnel measurements to assess the suitability of each method. The effect of each flow control device on the flow is examined based on the DES results on the finer mesh. Results agree well with the experimental findings and show that a newly proposed flap device outperforms traditional solutions for flatback airfoils. In terms of numerical modelling, the more expensive DES approach is more suitable if the wake frequencies are of interest, but the simplest 2D RANS simulations can provide acceptable load predictions.

Flow Control Devices in Steam Assisted Thermal Applications: A Way to Optimize Both Steam Injection and Fluids Production

2021 ◽  
Author(s):  
Da Zhu ◽  
Alberto Uzcategui
Keyword(s):  
High Pressure ◽  
Flow Control ◽  
Fluid Dynamic ◽  
Steam Injection ◽  
Control Device ◽  
Flow Loop ◽  
Pressure Drops ◽  
Steam Flooding ◽  
Flow Control Devices ◽  
Control Devices

Abstract Flow Control Device (FCD) completions in steam assisted thermal applications have been implemented in several places: Canada, California, China, Oman and Colombia, among others. Such completion configurations have been more common in recent years to mitigate or avoid uneven and/or improper steam placement and steam breakthrough, which are some of the critical issues operators have experienced in these developments. This study presents different FCD technologies designed to optimize the steam injection and fluids production for diverse steam assisted applications including SAGD, CSS and Steam Flooding. Three FCD technologies are introduced: (i) supersonic steam injection FCD, (ii) steam choking FCD and (iii) multi-directional FCD. Extensive Computational Fluid Dynamic (CFD) simulations, analytic near-wellbore simulations and flow loop testing were conducted to evaluate the performance of the three technologies: (i) the supersonic steam injection FCD showed a high pressure recovery (therefore, less upstream pressure requirements) and a reduction of the cumulative steam-oil ratio, (ii) the steam choking FCD demonstrated the highest steam choking capability for these type of devices and (iii) the multi-directional FCD showed promising results for CSS applications to allow for supersonic steam injection during the injection phase and steam choking capabilities during the production phase Common FCD deployment risks such as erosion, scaling potential and high pressure drops were reviewed to provide the reader with a high level understanding of the factors which could induce these issues. Finally, field data where FCD completions have been installed is presented to compare the FCD wells performance versus conventional well designs and illustrate the success of these completions strategies. Keywords: flow control devices, supersonic steam injection, steam choking

scholarly journals Review of Flow‐Control Devices for Wind‐Turbine Performance Enhancement

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1268
Author(s):  
Md. Zishan Akhter ◽  
Farag Khalifa Omar
Keyword(s):  
Flow Control ◽  
Wind Turbine ◽  
Performance Enhancement ◽  
Turbine Blades ◽  
Control Mechanisms ◽  
Power Sources ◽  
Turbine Performance ◽  
Flow Control Devices ◽  
Cost Of Energy ◽  
Control Devices

It is projected that, in the following years, the wind‐energy industry will maintain its rapid growth over the last few decades. Such growth in the industry has been accompanied by the desirability and demand for larger wind turbines aimed at harnessing more power. However, the fact that massive turbine blades inherently experience increased fatigue and ultimate loads is no secret, which compromise their structural lifecycle. Accordingly, this demands higher overhaul‐and‐maintenance (O&M) costs, leading to higher cost of energy (COE). Introduction of flow‐control devices on the wind turbine is a plausible solution to this issue. Flow‐control mechanisms feature the ability to effectively enhance/suppress turbulence, advance/delay flow transition, and prevent/promote separation, leading to enhancement in aerodynamic and aeroacoustics performance, load alleviation and fluctuation suppression, and eventually wind turbine power augmentation. These flow‐control devices are operated primarily under two schemes: passive and active control. Development and optimization of flow‐control devices present the potential for reduction in the COE, which is a major challenge against traditional power sources. This review performs a comprehensive and up‐to‐date literature survey of selected flow‐control devices, from their time of development up to the present. It contains a discussion on the current prospects and challenges faced by these devices, along with a comparative analysis centered on their aerodynamic controllability. General considerations and conclusive remarks are presented after the discussion.

scholarly journals The flow past a flatback airfoil with flow control devices: benchmarking numerical simulations against wind tunnel data

2020 ◽  
Vol 5 (3) ◽  
pp. 911-927
Author(s):  
George Papadakis ◽  
Marinos Manolesos
Keyword(s):  
Wind Tunnel ◽  
Flow Control ◽  
Control Device ◽  
Root Region ◽  
Flow Past ◽  
Flow Control Devices ◽  
Control Devices ◽  
Rans Simulations ◽  
Experimental Findings ◽  
Flatback Airfoil

Abstract. As wind turbines grow larger, the use of flatback airfoils has become standard practice for the root region of the blades. Flatback profiles provide higher lift and reduced sensitivity to soiling at significantly higher drag values. A number of flow control devices have been proposed to improve the performance of flatback profiles. In the present study, the flow past a flatback airfoil at a chord Reynolds number of 1.5×106 with and without trailing edge flow control devices is considered. Two different numerical approaches are applied, unsteady Reynolds-Averaged Navier Stokes (RANS) simulations and detached eddy simulations (DES). The computational predictions are compared against wind tunnel measurements to assess the suitability of each method. The effect of each flow control device on the flow is examined based on the DES results on the finer mesh. Results agree well with the experimental findings and show that a newly proposed flap device outperforms traditional solutions for flatback airfoils. In terms of numerical modelling, the more expensive DES approach is more suitable if the wake frequencies are of interest, but the simplest 2D RANS simulations can provide acceptable load predictions.

scholarly journals Computational Modeling of Gurney Flaps and Microtabs by POD Method

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2091 ◽  
Author(s):  
Unai Fernandez-Gamiz ◽  
Macarena Gomez-Mármol ◽  
Tomas Chacón-Rebollo
Keyword(s):  
Flow Control ◽  
Computational Cost ◽  
Aerodynamic Performance ◽  
Design Parameters ◽  
Cfd Simulations ◽  
Passive Flow Control ◽  
Gurney Flaps ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Control Devices

Gurney flaps (GFs) and microtabs (MTs) are two of the most frequently used passive flow control devices on wind turbines. They are small tabs situated close to the airfoil trailing edge and normal to the surface. A study to find the most favorable dimension and position to improve the aerodynamic performance of an airfoil is presented herein. Firstly, a parametric study of a GF on a S810 airfoil and an MT on a DU91(2)250 airfoil was carried out. To that end, 2D computational fluid dynamic simulations were performed at Re = 106 based on the airfoil chord length and using RANS equations. The GF and MT design parameters resulting from the computational fluid dynamics (CFD) simulations allowed the sizing of these passive flow control devices based on the airfoil’s aerodynamic performance. In both types of flow control devices, the results showed an increase in the lift-to-drag ratio for all angles of attack studied in the current work. Secondly, from the data obtained by means of CFD simulations, a regular function using the proper orthogonal decomposition (POD) was used to build a reduced order method. In both flow control cases (GFs and MTs), the recursive POD method was able to accurately and very quickly reproduce the computational results with very low computational cost.

Sign in / Sign up

Export Citation Format

Share Document