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

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

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

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  1. Evaluation of Elements of New Propulsion Technology for Littoral Combat Ships, LTS 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: 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 Friction drag reduction by using a part of exhaust products for ¨steam and gas lubrication¨ of the hull 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 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

  2. Fundamentals of Aluminum Combustion in Water 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, 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. 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.

  3. Al/H2O Marine Propulsion System Thermodynamic Analysis Constant volume and energy problem 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 Combustion composition 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

  4. Al/H2O Marine Propulsion System Thermodynamic 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

  5. Al/H2O Marine Propulsion System a) b) Examples of wet a) SFW, b) grinding of Al ; after (I suggested in 1993) P.Fleming and K.Uehara et al.

  6. 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

  7. Al/H2O Marine Propulsion System Conventional vs. jet drive (The Pursuit Marine Drive, UK) units comparison

  8. 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

  9. Hull Drag Reduction Concept by ¨Gas Lubrication¨ The schematic of the injection system on planing catamarans Cucci (1992)

  10. 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

  11. 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)

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