PowerPoint Presentation

Numerical investigation on aerodynamic performance of darrieus H-rotor wind turbine.-PRESENTED BY,AKRAM MBHARATH N

Vertical-axis wind turbines (VAWTs)Main rotor shaft is set transverse to the wind. allows the generator and gearbox to be located close to the ground. facilitating service and repairremoves the need for wind-sensing and orientation mechanisms.

principles to extract wind power Aerofoil drag method, Aerofoil lift principle

AdvantagesCompact design.Easier connection to gears/generator. Easier blade control. Lower fatigue.

objectiveTo increase the performance of H-Rotor Darrieus turbine A detailed numerical analysis has been made without changing the geometry. it is important to prevent the negative torque that forms in the adverse direction .A new design has been put forward by introducing two barrier plates

Workflow of the model -

Generation of a simplified 2D CAD model and computational domain High quality meshing of the domain Setting the Fluent Solver and calibrating the model Optimization of the Transition Turbulence model Post-processing results.

PROBLEM FORMULATION

GEOMETRICAL MODEL

Number of blades3Blade AirfoilNACA 0021Blade length3mBlade chord (c)0.6mRadius (R)0.8mRotational speed (n)20-40 rpmWind speed (V)8 m/sTip Speed Ratio0.2-3.5

The main features of the Validation model:

COMPUTATIONAL FLUID DYNAMICS (CFD) SIMULATION

In the present study, ANSYS Fluent 15 trade software has been used .By using it, the Darrieus wind rotor with and without barrier in the static position has been analysed.To do the numerical analysis in a shorter time, the model has been formed to have 2D.The unsteady flow is solved by using the Sliding Mesh Model (SMM).

Boundary conditions

Blades-WALL. Line to the left of the box- VELOCITY INLET Line on the right of the box - PRESSURE OUTLET Lateral lines of the box- SYMMETRY The Symmetry BC is useful because it allows the solver to consider the wall as part of a larger domain. Finally it can substantially reduce the size of the box. The contact region- INTERFACE

Meshing High quality non conformal unstructured mesh ANSYS Meshing advanced sizing functionsInflation tool was used to generate 20 levels of quadrangular cellsgrowth rate of 1.1

Mesh Independent TestSeveral different two-dimensional, unstructured grids Range: 33000 up to 120345 cells test shows that more than 92450 cells lead to a relative variation of the output quantity below 1.3%

Governing Equations

Turbulence Model Validation

Problem Setup In Fluent

Verification of the Simulation Results with Published Experimental Results

DESIGN OF THE DARRIUS WIND ROTOR AND THE BARRIER ARRANGEMENT

MESH GENERATION AND BOUNDARY CONDITIONS FOR PRESENT MODEL

Aerofoils No slip WallBarriers No slip Rotating wSliding Mesh Model (SMM) realizable k turbulence model all

RESULTS AND DISCUSSION

Velocity contourPressure contour

Velocity contour with barrierPressure contour with barrier

Different Positions of Barrier1 relative to wind rotor (Angles and will be taken 80)

CONCLUSION AND FUTURE WORK

A barrier arrangement - to prevent the negative torque.A comparison between the results obtained through published experiments and numerical analysisBest performance for wind rotor is obtained at = 80 and = 80.when barrier put before wind rotor in the side ends as in position A

Future Work: Mechanical analysis will be made through wind rotor after put barrier in front of wind rotor and study stress distribution and vibration on blade after increase pressure on blade and optimize the thickness of blade

THANK YOU