TYPES OF DOCKS

DRAG REDUCTION THROUGH AIR LUBRICATIONJAY PRAKASH JHA2015AMX155509

1

SCOPE OF PRESENTATION:Background of the projectFrictional Drag: ReviewWays for reduction of FDRAdvantages of ALS Techniques of ALSFuture projectsOutcomes TimelineReferences

2

BACKGROUND

The use of air lubrication has been the goal of naval architects for many years (patents from the 1800s).Stepped Hulls have been employed on planing craft and amphibious aircraft since the 1920s.But, gas injection for drag reduction has found practical application on some high speed moving vehicles.And, its use on surface ships is under active development.

3

FRICTIONAL DRAG: A BRIEF REVIEWVelocity of the fluid on the surface is same as the velocity of the surface due to no-slip conditionMomentum is transferred from free stream to near-wall-region by structures in the boundary layer and they shear

4

REDUCTION OF FRICTIONAL DRAGProven ways to reduce frictional drag: 1. Reduce density or viscosity of fluid (air lubrication) 2. Alter the momentum transport in the boundary layer 3. violate the no slip condition (encountered in MEMS scale devices)

5

ADVANTAGES OF AIR LUBRICATION:POTENTIAL DRAG REDUCTION BENEFITS

INCREASED SHIP PERFORMANCEREDUCED FUEL USAGE AND COST

REDUCE CO2 AND OTHER EMISSIONS (NOX AND SOX)

6

AIR REDUCTION FDR TECHNIQUES:BUBBLE DRAG REDUCTION(BDR)AIR LAYER DRAG REDUCTION(ALDR)PARTIAL CAVITY DRAG REDUCTION(PCDR)

7

FUTURE PROJECTSAir lubrication systemBubbles generated by blower reduce the frictional resistance between the vessels bottom and the sea water.

Estimated CO2 Reduction : 10%Already installed on heavy lift vessels YAMATAI built by Mitsubishi Heavy Industries. Will also undergo verification tests on a bulk carrier. C/O MHIM/V Yamatai, M/V Yamato

Length overall: 162.0m Beam: 38.0m Max. draught: 6.34m Gross ton: 14,538GT Deadweight: 19,500 DWT

8

9

MECHANISM OF OPERATION

10

OUTCOMES OF THE PROJECT1. Study of the types of AIR LUBRICATION TECHNIQUES and their methodology2. Calculation of Drag Percentage Reduction taking a conventional ship and comparing the results3. Basic CFD studies of a vessel fiited with ALS4. Calculation of increase in efficiency and savings using empirical methods.5. Calculation of cost benefit analysis6. Energy saving calculation7. Life cycle cost estimate8. Calculation on a present WARSHIP OUTCOMES BASED ON NUMERICAL, THEORETICAL AND BASIC COMPUTATIONAL STUDIES

11

TIMELINE

12

TIMELINE

13

TIMELINE

14

TIMELINE

15

REFERENCES:1. Ceccio, S.L. "Friction Drag Reduction of External Flows with Bubble and Gas Injection," Annual Review of Fluid Mechanics, Vol. 42

2. Ceccio, S.L., Perlin, M. and Elbing, B.R., A cost-benefit analysis for air layer drag reduction Proc. Int. Conf. On Ship Drag Reduction- SMOOTH-SHIPS, Istanbul, Turkey. 2010

3. Gokcay, S., Insel, M., and Odabasi, A.Y. Revisiting artificial air cavity concept for high speed craft. Ocean Engineering, 31

4. Hoang, C. L., Toda, Y., and Sanada, Y. Full scale experiment for frictional resistance reduction using air lubrication method, Proc. of the Nineteenth International Offshore and Polar Engineering Conference, 812-817, 2009

5. Kodama, Y., Kakugawa, A., Takahashi, T., and Kawashima, H. Experimental study on microbubbles and their applicability to ships for skin friction reduction. International Journal of Heat Fluid Flow, 21:58288. 2000

6. Latorre, R., Ship hull drag reduction using bottom air injection. Ocean Engineering, 24(2),. 1997

7. Mizokami, S., Kawakita, C., Kodan, Y., Takano, S., Higasa, S., & Shigenaga, R. "Experimental Study of Air Lubrication Method and Verification of Effects on Actual Hull by Means of Sea Trial." Mitsubishi Heavy Industries Technical Review, 47(3), 41-47, 2010.

8. Proceedings of the International Symposium on Seawater drag reduction. Newport, Rhode Island. 22-23 July, 1998

16

THANK YOU