Presentation on theme: "OptiMax Dynamic, LLC Dr. James C. Huan OptiMax Dynamic, LLC August, 2014."— Presentation transcript:
OptiMax Dynamic, LLC Dr. James C. Huan OptiMax Dynamic, LLC August, 2014
OptiMax Dynamic, LLC 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
OptiMax Dynamic, LLC Marine animals Chose it Over Millions of Years of Natural Selection Caudal Fin A fundamental feature of Impulsive Propulsion is the impulsive jet flow characterized by well-structured large thrust vortices such as vortex rings. 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. Squid contracts body muscle to generate impulsive jet through its siphon; Squid is able to generate perfect vortex rings. https://www.youtube.com/watch?v=bK5IdL23 AMs For the size of a giant squid and how quick it acts for its prey, watch TV news clip at: reverse Karman street a perfect vortex ring Fig.-1 chain-connected inclined vortex rings reverse Karman vortex street
OptiMax Dynamic, LLC First-order Theoretical Analysis 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 steady propulsion jet flow (unstable vortices turn into turbulence) impulsive propulsion jet flow from Jojn Dabiri, CalTech V inf V jet T Jet or Ideal Efficiency! 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 !)
OptiMax Dynamic, LLC Findings from Experimental Studies on Impulsive Jet Flow “A Universal Time Scale for Vortex Ring Formation” by Gharib, M.,et al., JFM, (1998). 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). Impulsive Jet could increase propulsive efficiency up to 50% over the steady jet (Ruiz, Whittlesey & Dabiri, JFM, 2011). from Jojn Dabiri, CalTech VRT Krieg & Mohseni, (J of Oceanic Eng.,2008) a VRT model vortex ring from piston-cylinder setup
OptiMax Dynamic, LLC Athletes Manually Use Impulsive Propulsion in Boat Racing moving direction a practical example of reverse Karman street ! 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; Analysis shows using piston-cylinder setup to expel water will be more efficient than oars (see analysis): Slip velocity: Power loss on blade: Power Input: Propulsive efficiency: Assume: (1) force, ‘N’, in blade normal dir.; (2) no friction. ideal efficiency only at ! an oar analysis model
OptiMax Dynamic, LLC Take a break here if you want ! 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 !
OptiMax Dynamic, LLC 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 Discharge process Continuous flow during a cycle valve opened valve closed
OptiMax Dynamic, LLC Side-Intake MIT Actual Configuration (1)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.
OptiMax Dynamic, LLC 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 control volume for MIT control volume for propeller PD efficiency is nearly a constant; PD efficiency is much higher than ND; ND efficiency is a nonlinear ‘‘bell curve’’. flow all in axial direction ! having swirl loss ! For MIT: (even without considering momentum augmentation from Vortex Ring)
OptiMax Dynamic, LLC 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!
OptiMax Dynamic, LLC 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, C Q, the more effective or compact. Axial-flow pump jet is the most compact propulsor in use ! For Axial-flow pump, C Q is not a const. because Q and n is in a very nonlinear relation. The highest C Q ever found is in ONR AxWJ-2 Pump Jet, C Q, ONR =0.85 ! MIT cylinder d and system D A typical axial-flow pump curve. The best efficiency C Q is around 0.55 For MIT, C Q is a constant and equals to Pump Jet D and MIT d relation: Fori.e. just makeMIT can be more effective ! Besides, because C Q, MIT is const., we can always increase n for large Q ! Using D instead of d:
OptiMax Dynamic, LLC Development plan for MIT (This slide is purposely blanked ! Interested readers can obtain the information through direct contacting us.)
OptiMax Dynamic, LLC 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