Performance Modeling of Ducted Vertical Axis Turbine Using Computational Fluid Dynamics

2013 ◽  
Vol 47 (4) ◽  
pp. 36-44 ◽  
Author(s):  
Prasun Chatterjee ◽  
Raymond N. Laoulache

AbstractVertical axis turbines (VATs) excel over horizontal axis turbines in their independent flow direction. VATs that operate in an enclosure, e.g., a diffuser shroud, are reported to generate more power than unducted VATs. A diffuser-shrouded, high solidity of 36.67%, three-blade VAT with NACA 633-018 airfoil section is modeled in 2-D using the commercial software ANSYS-FLUENT®. Incompressible, unsteady, segregated, implicit, and second order in time and space solver is implemented in association with the Spalart-Allmaras turbulent model with a reasonable computational cost. The computational results are assessed against experimental data for unducted VAT at low tip speed ratios between 1 and 2 for further numerical analysis on diffuser models. Different diffuser designs are investigated using suitable nozzle size, area ratio, length-to-diameter ratio and angles between the diffuser inner surfaces. The numerical model shows that, for a specific diffuser design, the ducted VAT performance coefficient can be augmented by almost 90% over its unducted counterpart.

Author(s):  
Anders Goude ◽  
Olov A˚gren

For commercial applications of marine current turbines, it can be useful to build several turbines close to each other in a farm, similar to wind turbine parks. To create a good farm configuration, the turbines’ mutual interaction needs to be studied. Here, to obtain detailed information, several turbines were simulated together using a 2D vortex method. To limit the computational cost, the vortex method was combined with known profile section data for the blades. First, a single turbine was compared against two turbines in close proximity. The two turbines were tested both with equal and opposite rotational direction, and the two blade pitch angles 0 and 3 degrees were tested. For both a single turbine and the two turbine case, a 3 degree pitch angle gave higher power coefficients than 0 degrees. The differences between 3 and 0 degrees were more significant for the single turbine. In all cases, the two turbine system had higher power coefficient per turbine than the single turbine. A five turbine park was simulated with three different combinations, one with all turbines on a row, and two with a zigzag pattern, where the difference was that the last simulation had larger turbines than the other two. For 0 degrees incident flow angle, the turbines on the row obtained the highest power coefficient, while the larger turbines in zigzag pattern obtained higher total power. The case with the turbines on the row was most insensitive to changes in flow direction, and for a 30 degree change, the row produced the highest total power as well. By locating the turbines inside a channel, all turbines obtained higher power coefficients, and the increase was largest for the large turbines, which blocked the channel to a larger extent.


1997 ◽  
Vol 119 (3) ◽  
pp. 610-616 ◽  
Author(s):  
S. Mochizuki ◽  
A. Murata ◽  
M. Fukunaga

The objective of this study was to investigate, through experiments, the combined effects of a sharp 180 deg turn and rib patterns on the pressure drop performance and distributions of the local heat transfer coefficient in an entire two-pass rib-roughened channel with a 180 deg turn. The rib pitch-to-equivalent diameter ratio P/de was 1.0, the rib-height-to-equivalent diameter ratio e/de was 0.09, and the rib angle relative to the main flow direction was varied from 30 ∼ 90 deg with an interval of 15 deg. Experiments were conducted for Reynolds numbers in the range 4000 ∼ 30,000. It was disclosed that, due to the interactions between the bend-induced secondary flow and the rib-induced secondary flow, the combination of rib patterns in the channel before and after the turn causes considerable differences in the pressure drop and heat transfer performance of the entire channel.


2016 ◽  
Vol 179 ◽  
pp. 875-887 ◽  
Author(s):  
Min-Hsiung Yang ◽  
Guan-Ming Huang ◽  
Rong-Hua Yeh

2021 ◽  
Vol 11 (3) ◽  
pp. 1033
Author(s):  
Jia Guo ◽  
Timing Qu ◽  
Liping Lei

Pitch regulation plays a significant role in improving power performance and achieving output control in wind turbines. The present study focuses on a novel, pitch-regulated vertical axis wind turbine (VAWT) with inclined pitch axes. The effect of two pitch parameters (the fold angle and the incline angle) on the instantaneous aerodynamic forces and overall performance of a straight-bladed VAWT under a tip-speed ratio of 4 is investigated using an actuator line model, achieved in ANSYS Fluent software and validated by previous experimental results. The results demonstrate that the fold angle has an apparent influence on the angles of attack and forces of the blades, as well as the power output of the wind turbine. It is helpful to further study the dynamic pitch regulation and adaptable passive pitch regulation of VAWTs. Incline angles away from 90° lead to the asymmetric distribution of aerodynamic forces along the blade span, which results in an expected reduction of loads on the main shaft and the tower of VAWTs.


2015 ◽  
Author(s):  
Nilima C. Joshi ◽  
Ayaz J. Khan

ost of the flow phenomena important to modern technology involve turbulence. Propellers generally operate in the very complex flow field that may be highly turbulent and spatially non-uniform. Propeller skew is the single most effective design parameter which has significant influence on reducing propeller induced vibration. Up to date applications of propeller skew does not has a specified criteria for any turbulent model. This paper deals with the model which explains the effect of propeller skewness on hydrodynamic performance related to study of turbulent model via mathematical and numerical modeling. The simulation work is carried out using ANSYS-FLUENT software.


2020 ◽  
Vol 2020 (0) ◽  
pp. OS09-12
Author(s):  
Keisuke KITANO ◽  
Yasutaka HAYAMIZU ◽  
Takayuki SUZUKI ◽  
Shinichi MORITA ◽  
Shigeru OHTSUKA ◽  
...  

2021 ◽  
Vol 2021.59 (0) ◽  
pp. 07a5
Author(s):  
Keisuke KITANO ◽  
Yasutaka HAYAMIZU ◽  
Takayuki SUZUKI ◽  
Shigeru OHTSUKA ◽  
Shinichi MORITA ◽  
...  

2019 ◽  
pp. 29-55
Author(s):  
Grady Koch ◽  
Elias Koch

Author(s):  
Jialun Liu ◽  
Robert Hekkenberg ◽  
Bingqian Zhao

Ships that equipped with flapped rudders have better manoeuvring performance than ships fitted with traditional spade rudders. Moreover, this advantage is achieved without significantly affecting the ship’s resistance during normal cruising. Flapped rudders are, therefore, favourable for ships that require high manoeuvring performance and sail long distance. Nowadays, there is a trend of using twin flapped rudders on newly built inland vessels in the Yangtze River. To properly design these ships and analyse their manoeuvring performance, the hydrodynamic characteristics of the flapped rudders are required. In this paper, a RANS study is performed to analyse the impacts of the three main properties of a flapped rudder on its hydrodynamic coefficients. The target properties are the rudder profile, the flap-linkage ratio (the flapped angle relative to the rudder chord line divided by the applied rudder angle), and the flap-area ratio (the sectional area of the flap divided by the total sectional area). The RANS simulations are carried out with commercial meshing tool ANSYS Meshing and CFD solver ANSYS Fluent.


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