Use of Magnus Effect Rotors as Wind Turbines for Solar Chimney Power Plants

Transcription

1 Use of Magnus Effect Rotors as Wind Turbines for Solar Chimney Power Plants Presented by: Mohammed Abdul Hamid Abdul Latif Advisor: Prof. Mohamed Amr Serag El-Din

2 Outline Introduction Objectives Methodology Results Conclusions Recommendations Acknowledgments

3 Introduction Solar Chimneys Parameters: Collector Area (Power Input) Absorber Specific Heat Capacity (Storage) Tower Length (Acceleration) Diameter (Output Velocity) Turbine Operating Conditions (Power Output) Efficiency (Power Output) Figure 1: Solar Chimney Power Plant Principle of Operation

4 Introduction Solar Chimneys Research to Reduce Costs: Improvements in Construction: Solar Chimneys on Mountains. Floating Solar Chimney. Cheaper Turbines Improvements in Performance: Turbine Layout Turbine Configurations

5 Introduction Magnus Effect Proposal: Use Magnus Effect Rotors as Turbine. Magnus Effect: Figure 5: Effect of Increasing Cylinder rotational speed on lift force

6 Introduction Magnus Effect Applications: Flettner Ships Magnus Generator Figure 6: Flettner Ship using Magnus rotors for thrust Figure 7: Turbine Utilizing Magnus Effect

7 Introduction Figure 8: Top View of Proposed System Figure 9: Solid model of Proposed System

8 Introduction Magnus Effect Rotors Vs. Airfoils: Manufacturing costs reduction Maintenance costs reduction Ease of Control Power Consumption

9 Objectives Investigate possibility of proposed system. Study input variables: Cylinder and disc diameters Cylinder and disc rotational speeds Number of cylinders Free stream velocity Identify most dominant variable and its effect on the performance. Study performance through variables: Lift and drag forces generated Pressure drop across the turbine Power output.

10 Methodology Experimental: Inaccurate results due to scaling Tedious Expensive Numerical model using Fluent: Navier-Stokes Equations Finite Difference Method

11 Methodology Non-Dimensional Analysis: Similarity Reduction of Variables Input: Variables Cylinder Radius (r) Disc Radius (R) Cylinder Tangential Velocity (ω)( Disc Tangential Velocity (Π)( Number of Cylinders (n) Airspeed (v) Coefficients Cylinder Tangential Velocity to Airspeed Ratio (ωr( r / v) (CAR) Disc Tangential Velocity to Airspeed Ratio (ΠR( R / v) (DAR) Number of Cylinders (n) Ratio of Cylinder to Disc radii (r / R) Table 1: Variables and Coefficients used in the System

12 Methodology Output: Lift Coefficient Drag Coefficient Pressure Drop Coefficient Efficiency Input Variable Variations: Number of Cylinders (n):

13 Methodology Cylinder to Disc Radii (r / R) CAR: DAR:

14 Methodology

15 Methodology Fluent Parameters: Rotating Frame Equations Viscosity: k-εk Turbulence Model: Robust Economic Accurate Renormalization Group (RNG): Accuracy in Swirling and Strained Flows Updated Values according to Analytical Equations

16 Methodology Wall Treatments: Enhanced Near Wall: Accurate with flows experiencing: High Reynolds Number Swirl Severe Pressure Gradients Solver: Segregated Implicit Discretization Scheme: QUICK High Accuracy with quadrilateral meshes Pressure Discretization: PREssure STaggering Option (PRESTO!): High swirling and high speed rotating flows

17 Methodology Gradient Evaluation: (Node Based Derivatives): Triangular or Tetrahedral Meshes Accuracy. Pressure Velocity Coupling: Semi-Implicit Method For Pressure Linked Equations Consistent (SIMPLEC): Complicated flows due to Under-Relaxation. Reliable with minimum computational effort. Termination Accuracy = 1 X 10-6

18 Methodology Mesh Accuracy: y+ < 5 10 cells in viscosity-affected near-wall region (Re Y < 200). Mesh Validation: Solve simple configuration analytically.

19 Results Fluent Output: Relative and absolute velocity vectors and the streamlines depicting the flow. Static pressure distribution over the rotating cylinder. Force component parallel to the free stream (radial to disc). Force component perpendicular to the free stream (tangential to disc). Pressure difference at locations before and after the turbine. Shear forces acting on the cylinder due to its rotation.

20 Results

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31 Conclusions Max. Efficiency = 86 %: DAR = 1 CAR = 2Π2 Number of Cylinders: No Effect on Force. Increases Power Output. Minimum Gap.

32 Conclusions Disc and Cylinder Radii: Cylinder Radius increased Force. Tangential Velocity components. System Efficiency depends strongly on Parameters.

33 Recommendations 1. Advanced Optimization Schemes. 2. Include Height:

34 Recommendations 3. Staggered Cylinder Arrangement. 4. Analyze proposed Turbine coupled with Solar Chimney. 5. Experimental Validation.