Marine impulse thruster (MIT) from Efficiency, linearity and Effectiveness point of view

1. Marine impulse thruster (MIT) fromEfficiency, linearity and Effectiveness point of view Dr. James C. Huan OptiMax Dynamic, LLC August , 2014

2. Overview • Why Impulsive or Unsteady Propulsion? • Marine animals chose it over millions of years of natural selection; • Theory and laboratory tests proved its superiorities; • Athletes manually use it in boat racing. • Why Not Impulsive Propulsion for All Marine Vehicles? • Man-made device to achieve a simple and efficient cycle for Impulsive Propulsion for marine vehicles is the challenge! • Patented Side-Intake Concept for MIT Overcame the Challenge! • Working principle of the Side-Intake MIT; • MIT examined from Efficiency, Linearity and Effectiveness perspectives; • Development plan for MIT. • A View for the Future

3. Why Impulsive or Unsteady Propulsion? A fundamental feature of Impulsive Propulsion is the impulsive jet flow characterized by well-structured large thrust vortices such as vortex rings. • Marine animals Chose it Over Millions of Years of Natural Selection reverse Karman vortex street Caudal Fin • Fish impulsively sweep its caudal fin to • generate a wavy impulsive jet (see Fig.-1); • DPIV revealed chain-connected inclined • vortex rings in the jet flow from fish. chain-connected inclined vortex rings Fig.-1 • Squid contracts body muscle to generate • impulsive jet through its siphon; • Squid is able to generate perfect vortex rings. reverse Karman street For the size of a giant squid and how quick it acts for its prey, watch TV news clip at: a perfect vortex ring https://www.youtube.com/watch?v=bK5IdL23AMs

4. Why Impulsive or Unsteady Propulsion? • First-order Theoretical Analysis Vinf Vjet steady propulsion jet flow (unstable vortices turn into turbulence) T from JojnDabiri, CalTech Jet or Ideal Efficiency! • Energy losses in steady propulsion devices • (propellers or impeller-driven pump jets): • viscous shear loss (vorticity instability and turbulence) • cavitation loss • slip losses including axial and tangential impulsive propulsion jet flow • Impulsive Jet from piston-cylinder setup: • minimum loss from vorticity instability and turbulence; • axial slip loss only, meaning achieving ideal efficiency. a perfect jet model (only axial flow velocity !)

5. Why Impulsive or Unsteady Propulsion? • Piston-cylinder setup is ideal for optimum Vortex Ring generation • resulting in a momentum augmentation in jet flow through: • ambient mass entrenchment into the Vortex Ring; • over-pressure at jet exit to accelerate the Vortex Ring (Gharib, JFM, 1998). • Findings from Experimental Studies on Impulsive Jet Flow • Impulsive Jet could increase propulsive efficiency up to • 50% over the steady jet (Ruiz, Whittlesey & Dabiri, JFM, • 2011). “A Universal Time Scale for Vortex Ring Formation” by Gharib, M.,et al., JFM, (1998). a VRT model from JojnDabiri, CalTech VRT Krieg & Mohseni, (J of Oceanic Eng.,2008) vortex ring from piston-cylinder setup

6. Why Impulsive or Unsteady Propulsion? • Oar cycle achieves efficient impulsive • propulsion, but manually: • impulsively expel water to maximize • the reverse Karman vortex for thrust; • recover oar through air for minimum • energy waste; moving direction • Athletes Manually Use Impulsive Propulsion in Boat Racing • Analysis shows using piston-cylinder • setup to expel water will be more • efficient than oars (see analysis): Assume: (1) force, ‘N’, in blade normal dir.; (2) no friction. a practical example of reverse Karman street ! Slip velocity: Power loss on blade: Power Input: Propulsive efficiency: an oar analysis model ideal efficiency only at !

7. Why not Impulsive Propulsion for All Marine Vehicles ? • Give a Summary: • Impulsive Propulsion is proved to be superior over Steady Propulsion. • Piston-cylinder setup is ideal for Impulsive Propulsion. • Then, why not Impulsive Propulsion? • Man-made device to achieve a simple and efficient cycle for • Impulsive Propulsion for all marine vehicles is the challenge ! • Patented Side-Intake concept for MIT for the first time overcame the • challenge ! Take a break here if you want !

8. Patented Side-Intake Concept for MIT valve opened • Working Principle of the Side-Intake MIT System • open intake holes near discharging end. • require a valve to open and close intake holes. • separate cylinder with a dry and a wet compartment during piston motion. • achieve oar-like cycle, but under water. • need two cylinders for continuing water flow from inlet to jet exit. Intake process valve closed Discharge process Continuous flow during a cycle

9. Patented Side-Intake Concept for MIT • Side-Intake MIT Actual Configuration jet nozzle; (2) 4 cylinders; (3) 4 inner ring rotational valves; (4) ball bearings; (5) permanent magnets; (6) 4 electrical coil winding pats; (7) 4 pistons; (8) 4 absorbing springs, one for each piston; (9) baffle cap. MIT is similar to Axial Piston Pump, but for flow rate and momentum producing.

10. Patented Side-Intake Concept for MIT • MIT examined from Efficiency, Linearity and Effectiveness perspectives • MIT can have a more than 30% efficiency increase over the best marine • propulsor in use today • PD efficiency is nearly a constant; • PD efficiency is much higher than ND; • ND efficiency is a nonlinear ‘‘bell curve’’. For MIT: flow all in axial direction ! having swirl loss ! control volume for MIT (even without considering momentum augmentation from Vortex Ring) control volume for propeller

11. Patented Side-Intake Concept for MIT • MIT examined from Efficiency, Linearity and Effectiveness perspectives(cont’d) • MIT is a linear performer, which is extremely important for vehicle’s • acceleration and maneuverability ! • because MIT is a PD pump and its is nearly a constant • regardless of changes to a vehicle’s load condition (e.g. during • acceleration or maneuvering). • MIT is more effective than the most effective pump jet ever designed • Effectiveness of a power machine is a power density question. • For a propulsor, ideally to have the most compact system to generate • a given thrust power without sacrificing its efficiency. Let’s look at the thrust equation: • To Increase for larger T leads to larger slip loss and so • sacrifices efficiency, not good ! • Ideally, it is to increase flow rate, , for larger T. • However, is proportional to a propulsor’s size. • The effectiveness question is to answer: among the same size of • propulsors, which propulsor can produce the most flow rate, ? Let’s do an analysis!

12. Patented Side-Intake Concept for MIT • MIT is more effective than the most effective pump jet ever designed (cont’d) • The capacity coefficient, where: n is RPM, D is the diameter of the propulsor • determines the effectiveness or compactness of a propulsor ! • For the same diameter and RPM, the larger, CQ , the more effective or compact. • Axial-flow pump jet is the most • compact propulsor in use ! • For Axial-flow pump, CQ is not a const. • because Q and n is in a very nonlinear • relation. • The highest CQ ever found is in ONR AxWJ-2 Pump Jet, CQ, ONR =0.85 ! • For MIT, CQ is a constant and equals to MIT cylinder d and system D A typical axial-flow pump curve. The best efficiency CQ is around 0.55 Pump Jet D and MIT d relation: Using D instead of d: For i.e. just make MIT can be more effective ! Besides, because CQ, MIT is const., we can always increase n for large Q !

13. Patented Side-Intake Concept for MIT • Development plan for MIT (This slide is purposely blanked ! Interested readers can obtain the information through direct contacting us.)

14. A View for the Future • MIT is a disruptive technology in maritime industry. • As a jet engine is the heart for an airplane, MIT is the heart for a • marine vehicle. • MIT powered by advanced electric drive will bring about a new • revolution in the industries of shipbuilding and maritime • transportation. Q & A