V.I. Golovitchev and L. Montorsi It is described a novel combustion (AL/H 2 O) system and high performance underwater jet engine for marine propulsion.

V.I. Golovitchev and L. Montorsi

It is described a novel combustion (AL/H2O) system and high performance underwater jet engine for marine propulsion based on the principle of the aeronautical ramjet engine and drag reduction concept, providing, as estimated, higher cruise speed (of about 100 knots) than state-of the-art marine propulsion technology together with simplicity, absence of moving underwater parts, complicated gearboxes, etc., by removal of gas turbines, diesel engine and props. The main elements of the propulsion technology are:

1. Al/H2O combustion activated by removal of Al oxides film by wet machining or SFSW (Submerged Friction Stir Welding) producing film-free surface and chips violently reacting with water. The steam and other (mostly H2) exhaust combustion products after production are directed beneath the hull

2. Friction drag reduction by using a part of exhaust products for ¨steam and gas lubrication¨ of the hull

3. The major part of exhaust products will be used to feed the underwater jet propulsor unit consisting of a nozzle assembly placed in the water under the vessel

Evaluation of Elements of New Propulsion Technology for Littoral Combat Ships, LTS

The movie (a clip from youtube.com) of the modern LTS (Visby corvette): it looks that the engine exhaust is not directed beneath a hull, but cooled and distributed along the ship boards

V.I. Golovitchev and L. Montorsi

Fundamentals of Aluminum Combustion in Water

The movie (a clip from youtube.com) is an illustration of Al/H2O combustion. In this case, the aluminum-ice, ALICE, slurry was used for rocket propulsion as it proved at Purdue University.

Aluminum has been selected as a perfect energy carrier. The chemical energy is tightly ¨packed¨ in the molecules, but Al is practically non-explosive. If aluminum is placed in the water solution, combustion turns it into aluminum hydroxide or oxide-hydroxides. The energy of this reaction can be estimated as follows:

or finally,

that is equivalent to the aluminum combustion in oxygen.

Since the aluminum is covered by the oxides film, the last one must be removed to initiate combustion. We proposed a new way how to do this in the water stream.

V.I. Golovitchev and L. Montorsi

Al/H2O Marine Propulsion SystemThermodynamic Analysis

CONU CONV PRES 10.00 ! atm TEMP 300.0 ! K REAC AL 0.150 REAC H2O(L) 0.850 TEST 2000. ! K END

INITIAL STATE: EQUILIBRIUM STATE: P (atm) 1.0000E+01 4.1329E+01 T (K) 3.0000E+02 1.3403E+03 V (cm3/gm) 1.2715E+02 1.2715E+02 H (erg/gm) -1.2542E+11 -1.2138E+11 U (erg/gm) -1.2671E+11 -1.2671E+11 S (erg/gm-K) 2.5040E+07 9.6512E+07 W (gm/mole) 1.9360E+01 2.0930E+01

Mole Fraction: initial products H2 0.0000E+00 2.4324E-01 O2 0.0000E+00 5.5410E-15 OH 0.0000E+00 7.0191E-09 H 0.0000E+00 1.5757E-07 H2O 0.0000E+00 6.7568E-01 O 0.0000E+00 4.1110E-15 H2O2 0.0000E+00 2.3122E-14 HO2 0.0000E+00 2.8559E-17 AL 1.5000E-01 1.1972E-19 AL2O3(S) 0.0000E+00 7.7162E-02 AL2O3(L) 0.0000E+00 3.9192E-03 Al2O3(g) 0.0000E+00 3.3873E-32 H2O(L) 8.5000E-01 1.5165E-21

Constant volume and energy problem

Combustion composition

V.I. Golovitchev and L. Montorsi

Al/H2O Marine Propulsion SystemThermodynamic Analysis

Parametric Analysis of Combustion

a) b)

a) Adiabatic flame temperature and b) fraction of hydrogen released by the aluminum oxidation with water for different initial pressures

V.I. Golovitchev and L. Montorsi

Al/H2O Marine Propulsion System

Examples of wet a) SFW, b) grinding of Al ; after (I suggested in 1993) P.Fleming and K.Uehara et al.

b)

a)

V.I. Golovitchev and L. Montorsi

Al/H2O Marine Propulsion System

The sketch of the AL/H2O combustion chamber

a)b)

a) View and b) concept behavior of a preliminary design of energy conversion system based on the aluminum combustion in water: the oxide films are removed

by machining

V.I. Golovitchev and L. Montorsi

Al/H2O Marine Propulsion System

Conventional vs. jet drive (The Pursuit Marine Drive, UK) units comparison

V.I. Golovitchev and L. Montorsi

Al/H2O Marine Propulsion System

Tested jet drive unit configuration of the Pursuit Marine Drive, UK

Steam and gas

Pursuit Marine Drive, UK, pump-jet unit,

Experimental set-up

Pursuit Marine Drive, UK, pump-jet unit operation driven by steam condensation

V.I. Golovitchev and L. Montorsi

Hull Drag Reduction Concept by ¨Gas Lubrication¨

The schematic of the injection system on planing catamarans Cucci (1992)

V.I. Golovitchev and L. Montorsi

Hull Drag Reduction Concept by ¨Gas Lubrication¨

Table: Illustration of ¨gas lubrication¨ efficiency

The Table for different hulls was taken from ¨Ship hull drag reduction using bottom air injection¨ by R. Latorre, Ocean Engng., vol, 24. 2, pp. 161-175, 1997

V.I. Golovitchev and L. Montorsi

Al/H2O Marine Propulsion System

Conclusions

We propose to integrate all three elements of the propulsion technology described above in a novel configuration of the LCS with the high propulsion efficiency and highly reduced vulnerability. The later feature is achieved by a removal of attributes of conventional marine propulsion system, i.e. jet engines, and hydrocarbon fuel tanks (kerosene and diesel oil) replaced by Al rods (or tubes)