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DESIGN ANALYSIS for a SMALL SCALE ENGINE. by Tim van Wageningen. Contents - Motivation - Concepts Performance Analysis Conclusions Questions. ±40 min. 2 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS . Nature Technology. small. large. scale →. Atalanta

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DESIGN ANALYSIS for a SMALL SCALE ENGINE


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    1. DESIGN ANALYSISfor a SMALL SCALE ENGINE by Tim van Wageningen

    2. Contents • - Motivation • - Concepts • Performance Analysis • Conclusions • Questions ±40 min 2 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS

    3. Nature Technology small large scale → Atalanta project 3 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS

    4. Micro Air Vehicle Flapping Wing Mechanism MAV • Designed by Casper Bolsman • 0.6 gram • Performance estimate: • 0.5 W power output • Needed power density of • system: 125 W/kg • 6 minutes of flight time with • 5% efficiency 4 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS

    5. MAV in Action 5 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS

    6. Hydrogen Peroxide • - Master thesis of ArjanMeskers at the PME • department, TU Delft • Chemical energy: high energy density • - Monopropellant • - Clean products: oxygen and water vapor • - Example catalysts: -Manganese oxide • -Silver • -Platinum 6 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS

    7. Catalytic Reaction in Action 7 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS

    8. Thesis Assignment • Find an engine concept that: • is suitable for the MAV • 125 W/kg • 5% efficiency • uses hydrogen peroxide as fuel 8 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS

    9. Possibilities 9 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    10. 3 different approaches Turbine Piston Cylinder + + + + + 10 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    11. Concept I: Tesla Turbine Engine • + Easy implementation • + Theory of Tesla Turbine • predicts good efficiency at • small scale • Conversion from rotation • to linear motion + + 11 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    12. Concept I: Tesla Turbine Engine + + 12 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    13. Concept II: Otto Engine • + Proven concept on regular • scale • Projects in literature show • bad performance because of • fluid leakage problem • - Implementation difficult + 13 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    14. Concept II: Otto engine + 14 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    15. Concept III: Hot Air Engine • + Easy implementation • + Promising scaling aspects • because heat transfer is more • effective • Poor performance on regular • scale + + 15 MOTIVATIONS - CONCEPTS – PERFORMANCE I / II / III - CONCLUSIONS

    16. Concept III: Hot Air Engine + + 16 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    17. Performance • - What influences the performance of • these concepts? • - Concept I • - Concept II • - Concept III • Are the concepts suited for the MAV? • Power density • Efficiency 17 MOTIVATIONS - CONCEPTS - PERFORMANCEI / II / III - CONCLUSIONS

    18. Concept I: Tesla Turbine Engine 18 MOTIVATIONS - CONCEPTS - PERFORMANCEI / II / III - CONCLUSIONS

    19. Concept I: Tesla Turbine Engine: model Assumptions: Laminar flow No entrance effects Incompressible fluid 19 MOTIVATIONS - CONCEPTS - PERFORMANCEI / II / III - CONCLUSIONS

    20. Power Efficiency Pressure difference Length of belts (radius of discs) Height of gap (spacing between discs) 20 MOTIVATIONS - CONCEPTS - PERFORMANCEI / II / III - CONCLUSIONS

    21. Measurements with small scale Tesla turbines Pressure difference: ~20 kPa Measured Performance 45 mW 18% efficiency Estimated power density: 2 W/kg [2] V.G. Krishnan et al. A micro Tesla turbine for power generation from low pressure heads and evaporation driven flows. Transducers, 11:1851 – 1854, June 2011. 21 MOTIVATIONS - CONCEPTS - PERFORMANCEI / II / III - CONCLUSIONS

    22. Concept I, Tesla Turbine Engine: conclusions • Power density is too low: • pressure difference • must be increased • considerably • Simple model + measurements • show that TTE is not suitable for the • current size MAV 22 MOTIVATIONS - CONCEPTS - PERFORMANCEI / II / III - CONCLUSIONS

    23. Concept II: Otto Engine 23 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    24. Concept II, Otto Engine: combining 3 models Catalytic Reaction Exhaust Flow Heat Loss + + 24 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    25. Catalytic Reaction: model Drop on a catalytic surface Similar conditions as during experiments Energy Balance: 25 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    26. Catalytic Reaction: model [1] A.J.H. Meskers. High energy density micro-actuation based on gas generation by means of catalyst of liquid chemical energy. Masters thesis, TU Delft, 2010. 26 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    27. Catalytic Reaction: high fuel concentrations 27 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    28. Exhaust Flow: model Compressible flow through a round nozzle Based on momentum equation 28 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    29. Heat transfer Heat is transferred via -conduction -convection -radiation 29 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    30. Concept II, Otto Engine: combining models + + = • Dealing with model uncertainties: 30 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    31. Otto Engine: observations -Reaction times are fast enough -Trade off for fuel used per cycle -Condensation in cylinder 31 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    32. Concept II, Otto Engine: Results • Model shows performance above • the current requirements of the • MAV (125 W/kg @ 5% efficiency) 32 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    33. Concept II, Otto Engine: considerations • Model neglects: • fluid leakage through cylinder/piston gap • fluid friction at exhaust • fuel delivery system • Condensation in cylinder problem • needs to be addressed 33 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    34. Concept III: Hot Air Engine 34 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    35. Concept III, Hot Air Engine: models Catalytic Reaction Heat Reservoirs Heat Loss + + 35 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    36. Concept III, Hot Air Engine: Catalytic Reaction Constant temperature Mass balance 36 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    37. Concept III, Hot Air Engine: Heat Reservoirs Under reversible conditions Estimate for heat transfer rates Schematic • Using definition • Fouriers law • Optimistic and • pessimistic value 37 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    38. Model Results + + = Resulting performance of model 38 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    39. Considerations for Small Scale Hot Air Engine • Model neglects losses of • fluid flow between piston cylinder gap • heat leakage of Decomposition Unit to • the working fluid 39 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    40. Conclusions for Small Scale Hot Air Engine • Heat transfer is not yet fast enough • on this scale, which results in low • performance • Concept III is not suited for the MAV 40 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    41. Overall Conclusions • Of the considered possibilities, the • small scale Otto engine is the best • option for the MAV: • Power density at 5% efficiency: • Concept 1: << 2 W/kg • Concept 2: 245 – 440 W/kg • Concept 3: 0.5 – 8 W/kg 41 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    42. Overall Conclusions • Actual implementation • of concept II requires • more detailed analysis: • - Solving the fluid leakage problem • - Fuel pump • Exhaust port • Condensation 42 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS

    43. Thank You! 43 MOTIVATIONS - CONCEPTS - PERFORMANCE I / II / III - CONCLUSIONS -END

    44. Detailed slides 44 DETAILED SLIDES

    45. Scaling? Engine 2 S = 0.5 L = 5 A = 2.5 V = 1.25 Engine 1 S = 1 L = 10 A = 10 V = 10 Scaling factor Length Area Volume 16 PERFORMANCE

    46. Approach of others? 6 PREMILAIRY RESEARCH

    47. Possibilities 7 PREMILAIRY REASEARCH

    48. Power Efficiency Pressure difference Length of belts (radius of disks) Height of gap (spacing between disks) 40 PERFORMANCE

    49. Energy flow in concepts Carnot cycle = 7 CONCEPTS

    50. Carnot Cycle zero power output! 8 PERFORMANCE