OptiMax Dynamic, LLC

MARINE IMPULSE THRUSTER (MIT) from

EFFICIENCY, LINEARITY and EFFECTIVENESS POINT OF VIEW

Dr. James C. Huan

OptiMax Dynamic, LLC

August , 2014

OptiMax Dynamic, LLC

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

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Why Impulsive or Unsteady Propulsion? 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=bK5IdL23AMs

For the size of a giantsquid and how quick it acts forits prey, watch TV news clip at:

reverse Karman street

a perfect vortex ring

Fig.-1

chain-connected inclined vortex rings

reverse Karman vortex street

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Why Impulsive or Unsteady Propulsion? 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)( infxjet, VVQT )2

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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 !)

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Why Impulsive or Unsteady Propulsion? 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 frompiston-cylinder setup

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Athletes Manually Use Impulsive Propulsion in Boat Racing

Why Impulsive or Unsteady Propulsion?

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):

γV sin

γVωR sinωR

ω

Slip velocity: sinVRuu ns Power loss on blade: )sin( VRNEblade

Power Input: RNEinput

Propulsive efficiency:R

V

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sin

Assume: (1) force, ‘N’, in blade normal dir.; (2) no friction.

aR

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ideal efficiency only at !

an oar analysis model2/

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Why not Impulsive Propulsion for All Marine Vehicles ?

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 !

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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.

Patented Side-Intake Concept for MIT

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Discharge processContinuous flow during a cycle

valve opened

valve closed

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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.

Patented Side-Intake Concept for MIT

OptiMax Dynamic, LLC

MIT examined from Efficiency, Linearity and Effectiveness perspectives

Patented Side-Intake Concept for MIT

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 !

ω

Propulsor to Power Input

ThrustV

Propulsor to Power Input

Power Thrust ship overall

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fluid to adddenergy kinetic totalpump efficiency electrical

and mechanical : m

For MIT: 1flow

const a and %90pump

idealjetoverallMIT

(even without considering momentum augmentation from Vortex Ring)

1m

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MIT examined from Efficiency, Linearity and Effectiveness perspectives (cont’d)

Patented Side-Intake Concept for MIT

MIT is a linear performer, which is extremely important for vehicle’s acceleration and maneuverability !

pump• 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.

)( infxjet, VVQT 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, ?

)( infxjet, VV

QQ

QLet’s do an analysis!

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Patented Side-Intake Concept for MIT MIT is more effective than the most effective pump jet ever designed (cont’d)

• The capacity coefficient,

3/nDQCQ 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 !

MIT cylinder d and system D

A typical axial-flow pump curve. The best efficiencyCQ is around 0.55

• For MIT, CQ is a constant and equals to

ratio) diameter to (stroke whereMIT Q, dLndQC // 3

)21/( DdPump Jet D and MIT d relation:

071.0/ 3nDQC MIT Q,

126.0 ONR Q,

MIT Q,

C

CFor i.e. just make 8.3 MIT can be more effective !

Besides, because CQ, MIT is const., we can always increase n for large Q !

Using D instead of d:

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Development plan for MIT

Patented Side-Intake Concept for MIT

(This slide is purposely blanked !Interested readers can obtain the information throughdirect contacting us.)

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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