The Numerical Simulation and Performance Assessment of Rim-Driven Turbine Akezhan Zholdybayev 2nd Year Master in Mechanical and Aerospace Engineering Supervisor: Associate Professor Basman Elhadidi Co-Supervisor: Associate Professor Luis Rojas-Solórzano Outline Introduction Background Hypothesis Literature Review Aim and objectives Methods Results & Analysis Conclusion and Future work References 2 Introduction The rising global temperature is pushing countries to seek alternative sources of energy One of the solutions is green energy sources However, less than 20% of the world energy is produced from these sources Nevertheless, there a great hydro energy potential which can be implemented in various ways One of them is the application of rim-driven turbines(RDT) 3 Background 4 The working principle of RDT turbines is similar to that of regular turbines with central hub The flow of water through the blades moves the blades converting kinetic energy of the fluid to electric energy Figure 1. Application areas (Hochhaus, 2010) Background. Why RDT turbines? 5 Figure 2. Advantages of RDT Application Areas 6 Water transfer system Sewage water flow Figure 3. Application areas Hypothesis 7 Doubling number of blades increase Power Output (PO) PO Lifetime? Figure 4. Effects of blades on PO & Lifetime Literature Review. Experimental studies 8 Focus on design of electromagnetic parts (Gieras et al., 2008; Kim et al., 2013; Djebarri et al., 2012; Djebarri et al., 2015). Rim turbine design is applied as a thruster (Kim et al., 2020), marine turbine (Djebarri et al., 2012; Xu et al., 2017; Kim et al., 2013), tidal turbine (Djebarri et al., 2014, 2015) Thus, there is a research gap on RDT turbines Figure 6. Experimental setup for RDT (Djebarri, 2015) Literature Review. Experimental Studies 9 Studies investigating the relationship of rpm and performance was done on Kaplan hydroturbines (Santoso et al., 2017). Results show that peak efficiency is achieved at 260 rpm with 60% load. 2 works focused on effect of polymer coatings. (Mineshima et al., 2019; Fialova et al., 2016). Results show that hydrophilic coating has better results in preventing blade erosion compared to hydrophobic coating Figure 7. RDT vs regular turbines(Song, 2022) Literature Review. Numerical studies 10 The experimental studies on turbines: Ka 4-70 duct propeller To study the effects of gap fluid (Jiang, 2022) on performance Conducted CFD with performance analysis(Song et al., 2021, 2022) Authors indicate, that the RDT have less cavitation inception. Yet, there are lack of studies confirming that Figure 8. Power curves (Song, 2022) Figure 9. Performance output vs time-step Literature Review. Numerical studies 11 The numerical studies on RDT design also focuses on thrusters. For instance, the CFD study comparing DT and RDT was conducted using k-omega model with MRF approach (Liu et al., 2021) They conclude that, the gap flow significantly reduces the RDT thrusters, showing worse performance numbers than DP thrusters Figure 10. Thrust coefficient vs Advance coefficient Literature Review: Conclusions and gaps 12 The shaftless design was applied in thrusters, tidal turbine, marine turbines, Kaplan hydroturbines, indicating the lack of study on RDT turbines. It was found that the following factors affect the power output: Blade design Operational velocities (RPM, TSR) The fluid flow through the center gap (Turbine case need to be checked) Literature material imply importance of blade erosion without addressing it in methods The current literature did not access RDT as a turbine given its installation flexibility Hypothesis 13 Series installation reduce pressure load on blades distributing it among turbines increasing lifetime Figure 5. Application areas Aim and objectives The aim of this work is to assess the RDT in generating electricity for a given inlet conditions. It will be achieved by the following objectives: Develop accurate numerical simulation Evaluate the results and draw conclusion Confirm hypothesis 14 Methods Generate a mesh for a turbine blade. Initially OpenProp tool will be used for training purpose then a commercial turbine blade will be used. Development of numerical simulation: Computational Domain with pressure & velocity inlets Meshing Solution method Post-processing 15 Methods. Computation Domain with velocity inlet 16 Figure 11. Geometry and Boundary conditions Inlet velocity, m/s D, cm L, cm , rad/s , rad/s No. of blades 1.25 24 30 11.47 126.15 3 Fluid type Density, kg/m³ Viscosity, kg/m*s Water 998.2 0.001 Table 1. Fluid details Table 2. Input details Methods. Computation Domain with pressure inlet 17 Figure 12. Geometry and Boundary conditions D, cm L, cm , Pa , Pa No. of blades MRF, rad/s 24 30 11.47 126.15 3 80.275 Table 3. Input details Methods. Meshing of 3 bladed turbine 18 Figure 13. Mesh of the domain Methods. Meshing of 6 bladed turbine 19 Figure 13. Mesh of the domain Methods. Meshing of series 3 bladed turbines 20 Figure 13. Mesh of the domain Methods. Solution Method 21 Since the case is a flow in a pipe, the pressure-velocity coupling solution method with least-squared cell based spatial discretization method is used. Solution method Pressure-Velocity Coupling Scheme Coupled Spatial Discretization Least Square Cell Based Momentum Second Order Upwind Turbulent Kinetic Energy Second Order Upwind Specific Dissipation Rate Second Order Upwind Table 4. Solution details Grid Independence Test 22 Figure 14. Grind Independence Power Curve Table 5. Test Results Mesh Density Local Minimum Size, mm Number of cells % Change Coarse 0.4 735366 0.62   Medium 0.32 807412 0.65 4% Fine 0.3 883408 0.67 3% Results & Analysis. 3 bladed single turbine 23 Figure 15. Pressure Side Figure 16. Suction Side 3 bladed single turbine. Fluid flow around blades 24 Figure 17. Flow around blades Results & Analysis. 3 bladed series turbines 25 Figure 18. Front Blade Pressure Figure 19. Back Blade Pressure Results & Analysis. 3 bladed series turbines 26 Figure 20. Front blade suction side Figure 21. Back blade suction side 3 bladed series turbine. Fluid flow around blades 27 Figure 22. Flow around blades Results & Analysis. 6 bladed single turbine 28 Figure 23. Pressure Side Figure 24. Suction Side 6 bladed single turbine. Fluid flow around blades 29 Figure 25. Fluid flow around blades Results & Analysis. Power Coefficient for velocity inlet 30 Figure 26. Power coefficient Results & Analysis. Power Coefficient 31 Figure 26. Power coefficient of each cases Results & Analysis. Generated Power 32 Figure 27. Generated Power Results & Analysis. Pressure Drop 33 Figure 28. Pressure Drop Conclusions 34 6 bladed single turbine demonstrated the highest efficiency indicating the increase in blades number positively affect turbines’ efficiency 3 bladed 2 turbines demonstrated lowest operating efficiency, yet introduction of 2nd turbine lead to significant increase Series connection of hydro turbines decrease overall pressure loads on the system approximately by 40% for the front turbine, increasing its lifespan and reducing fatigue, and cavitation Future Work Future work involving experimental setup, and CFD with sliding mesh is recommended References Kort, L., 1940. Elektrisch angertriebene schiffsschraube, German Patent : DE688114. Pierro, J. J., 1973. Gearless drive method and means. United States patent, US3708251. Edwards, I. J., 1988. Electric motor rotor comprising a propeller, British Patent, GB2200802. 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In 19th International Seminar on Hydropower Plants. 37 Thank you for your attention! www.nu.edu.kz image1.png image2.png image4.png image5.png image6.png image7.png image8.png image9.jpeg image10.jpeg image11.png image12.png image13.png image14.png image15.png image16.png image17.png image18.png image19.png image20.png image21.png image22.png image23.png image24.png image25.png image26.png image27.png image28.png image29.png image30.png image31.png image32.png image33.png image34.png image35.png image36.png image37.png image38.png image39.png image40.png image41.png image42.png image43.png image44.png image45.png image46.png image47.png image48.png image49.png image50.png image51.png image52.png image3.png