scholarly journals Characterization of aerodynamic performance of ducted wind turbines: A numerical study

Wind Energy ◽  
2019 ◽  
Vol 22 (12) ◽  
pp. 1655-1666 ◽  
Author(s):  
Vinit V. Dighe ◽  
Gael Oliveira ◽  
Francesco Avallone ◽  
Gerard J. W. Bussel
Keyword(s):  
Wind Turbines ◽  
Numerical Study ◽  
Aerodynamic Performance

scholarly journals Multi-element ducts for ducted wind turbines: A numerical study

2019 ◽  
Author(s):  
Vinit V. Dighe ◽  
Francesco Avallone ◽  
Ozer Igra ◽  
Gerard van Bussel
Keyword(s):  
Viscous Flow ◽  
Wind Turbines ◽  
Deflection Angle ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Viscous Effects ◽  
Duct Geometry ◽  
Total Thrust ◽  
Flap Deflection ◽  
Radial Gap

Abstract. Multi-element ducts are used to improve the aerodynamic performance of ducted wind turbines (DWTs). Steady-state, two-dimensional computational fluid dynamics (CFD) simulations are performed for a multi-element duct geometry, consisting of a duct and a flap; goal is to evaluate the effects on the aerodynamic performance of the radial gap length and the deflection angle of the flap. Solutions from inviscid and viscous flow calculations are compared. It is found that increasing the radial gap length results in an augmentation of the total thrust generated by the DWT, whereas a larger deflection angle has an opposite effect. A reasonable to good agreement is seen between the inviscid and viscous flow calculations, except for multi-element duct configurations characterized by large flap deflection angles. The viscous effects become stronger at large flap deflection angles, and the inviscid calculations are incapable to take into account this phenomenon.

scholarly journals Multi-element ducts for ducted wind turbines: a numerical study

2019 ◽  
Vol 4 (3) ◽  
pp. 439-449 ◽  
Author(s):  
Vinit V. Dighe ◽  
Francesco Avallone ◽  
Ozer Igra ◽  
Gerard van Bussel
Keyword(s):  
Viscous Flow ◽  
Wind Turbines ◽  
Deflection Angle ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Viscous Effects ◽  
Duct Geometry ◽  
Total Thrust ◽  
Flap Deflection ◽  
Radial Gap

Abstract. Multi-element ducts are used to improve the aerodynamic performance of ducted wind turbines (DWTs). Steady-state, two-dimensional computational fluid dynamics (CFD) simulations are performed for a multi-element duct geometry consisting of a duct and a flap; the goal is to evaluate the effects on the aerodynamic performance of the radial gap length and the deflection angle of the flap. Solutions from inviscid and viscous flow calculations are compared. It is found that increasing the radial gap length results in an augmentation of the total thrust generated by the DWT, whereas a larger deflection angle has an opposite effect. Reasonable to good agreement is seen between the inviscid and viscous flow calculations, except for multi-element duct configurations characterized by large flap deflection angles. The viscous effects become stronger at large flap deflection angles, and the inviscid calculations are incapable of taking this phenomenon into account.

scholarly journals Ducted wind turbines in yawed flow: A numerical study

2019 ◽  
Author(s):  
Vinit Dighe ◽  
Dhruv Suri ◽  
Francesco Avallone ◽  
Gerard van Bussel
Keyword(s):  
Wind Turbines ◽  
Urban Areas ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Flow Conditions ◽  
Actuator Disc ◽  
Duct Geometry ◽  
Yaw Angle ◽  
Surface Discontinuities

Abstract. Ducted Wind Turbines (DWTs) can be used for energy harvesting in urban areas where non-uniform flows are caused by the presence of buildings or other surface discontinuities. For this reason, the aerodynamic performance of DWTs in yawed flow conditions must be characterized. A numerical study to investigate the characteristics of flow around two DWT configurations using a simplified duct-actuator disc (AD) model is carried out. The analysis shows that the aerodynamic performance of a DWT in yawed flow is dependent on the mutual interaction between the duct and the rotor; an interaction that changes with duct geometry, AD loading and operating conditions. It is found that the duct cross-section camber not only offers insensitivity to yaw, but also a gain in performance up to a specific yaw angle; thereafter any further increase of yaw results in a performance drop.

scholarly journals Ducted wind turbines in yawed flow: a numerical study

2021 ◽  
Vol 6 (5) ◽  
pp. 1263-1275
Author(s):  
Vinit Dighe ◽  
Dhruv Suri ◽  
Francesco Avallone ◽  
Gerard van Bussel
Keyword(s):  
Wind Turbines ◽  
Urban Areas ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Actuator Disc ◽  
Duct Geometry ◽  
Wall Flow ◽  
Yaw Angle ◽  
Surface Discontinuities

Abstract. Ducted wind turbines (DWTs) can be used for energy harvesting in urban areas where non-uniform flows are caused by the presence of buildings or other surface discontinuities. For this reason, the aerodynamic performance of DWTs in yawed-flow conditions must be characterized depending upon their geometric parameters and operating conditions. A numerical study to investigate the characteristics of flow around two DWT configurations using a simplified duct-actuator disc (AD) model is carried out. The analysis shows that the aerodynamic performance of a DWT in yawed flow is dependent on the mutual interactions between the duct and the AD, an interaction that changes with duct geometry. For the two configurations studied, the highly cambered variant of duct configuration returns a gain in performance by approximately 11 % up to a specific yaw angle (α= 17.5∘) when compared to the non-yawed case; thereafter any further increase in yaw angle results in a performance drop. In contrast, performance of less cambered variant duct configuration drops for α>0∘. The gain in the aerodynamic performance is attributed to the additional camber of the duct that acts as a flow-conditioning device and delays duct wall flow separation inside of the duct for a broad range of yaw angles.

Numerical Study of the Roughness Influence on NACA 63-430 Profile Aerodynamic Performance

2016 ◽  
Vol 10 (4) ◽  
pp. 231
Author(s):  
Abdekarim Tebbal ◽  
Fethi Saidi ◽  
Boualem Noureddine ◽  
Bachir Imine ◽  
Benameur Hamoudi
Keyword(s):  
Numerical Study ◽  
Aerodynamic Performance

A torque matched aerodynamic performance analysis method for the horizontal axis wind turbines

Wind Energy ◽  
2013 ◽  
Vol 17 (11) ◽  
pp. 1727-1736 ◽  
Author(s):  
Ali Al-Abadi ◽  
Özgür Ertunç ◽  
Horst Weber ◽  
Antonio Delgado
Keyword(s):  
Performance Analysis ◽  
Wind Turbines ◽  
Aerodynamic Performance ◽  
Horizontal Axis ◽  
Analysis Method ◽  
Horizontal Axis Wind Turbines

Numerical Characterization of Hot Gas Ingestion Through Turbine Rim Seals

2016 ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Carl M. Sangan ◽  
James A. Scobie ◽  
Gary D. Lock
Keyword(s):  
Flow Rate ◽  
Numerical Study ◽  
Axial Flow ◽  
Radial Clearance ◽  
Buffering Effect ◽  
Hot Gas ◽  
Numerical Predictions ◽  
Wide Range ◽  
Thermal Buffering

This paper deals with a numerical study aimed at the characterization of hot gas ingestion through turbine rim seals. The numerical campaign focused on an experimental facility which models ingress through the rim seal into the upstream wheel-space of an axial-turbine stage. Single-clearance arrangements were considered in the form of axial- and radial-seal gap configurations. With the radial-seal clearance configuration, CFD steady-state solutions were able to predict the system sealing effectiveness over a wide range of coolant mass flow rates reasonably well. The greater insight of flow field provided by the computations illustrates the thermal buffering effect when ingress occurs: for a given sealing flow rate, the effectiveness on the rotor was significantly higher than that on the stator due to the axial flow of hot gases from stator to rotor caused by pumping effects. The predicted effectiveness on the rotor was compared with a theoretical model for the thermal buffering effect showing good agreement. When the axial-seal clearance arrangement is considered, the agreement between CFD and experiments worsens; the variation of sealing effectiveness with coolant flow rate calculated by means of the simulations display a distinct kink. It was found that the “kink phenomenon” can be ascribed to an over-estimation of the egress spoiling effects due to turbulence modelling limitations. Despite some weaknesses in the numerical predictions, the paper shows that CFD can be used to characterize the sealing performance of axial- and radial-clearance turbine rim seals.

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