1 / 20

Propulsion Train & Shaft Line Components

Propulsion Train & Shaft Line Components. Introduction. Reduction Gears - fast to slow Lubrication System - overcome friction Shaft components - turbines to the working medium (ocean) Propeller - transform rotational energy into thrust. Reduction Gears. Purposes

pilialoha-sean
Download Presentation

Propulsion Train & Shaft Line Components

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Propulsion Train & Shaft Line Components

  2. Introduction • Reduction Gears - fast to slow • Lubrication System - overcome friction • Shaft components - turbines to the working medium (ocean) • Propeller - transform rotational energy into thrust

  3. Reduction Gears • Purposes • Allow turbine and propeller to operate at most efficient speeds • Combine two turbines to common shaft

  4. Reduction Gears • Gear Types • Straight • excessive vibration • low power-transfer ability • Helical • Reduces vibration, quieter • Higher power transfer ability • Excessive axial thrust • Double Helical • Two sets of teeth cut at opposite angles • Eliminates axial thrust

  5. Reduction Gears • Reduction Process • Pinion (small) gear drives reduction (large) gear • Reduction ratio = turns of pinion : turns of reduction gear • Double-reduction: reduction in 2 steps (more compact design) • For naval reduction gears, normally 30:1

  6. Reduction Gears • Locked Train • Two sets of gears and shafts • Torque transmitted equally • Increases ability to transmit torque using smaller components • Turbine shafts connected to reduction gears by flexible couplings to allow for thermal expansion

  7. Shaft Turning/Jacking Gear • Electric motor that rotates reduction gears, turbines, and shaft w/o using steam • Cool down turbines after operation • Prior to startup for even heating • Position for maintenance • Can be used to lock shaft in place • In event of casualty (i.e., loss of lube oil)

  8. Shaft Bearings • Designed to support the moving parts of: • Shaft • Turbines • Thrust bearings • Absorb axial forces • Ex: Kingsbury Thrust bearing • Radial (Journal) bearings • Absorb radial forces

  9. Lube Oil System • Provide lubrication and remove heat generated by bearings in overcoming friction • Major components: • Sump • Pump • Strainer • Cooler • Bearings Cooler SW Moving Parts Strainer Pump Sump

  10. Lube Oil System • Lube oil can be kept in service for a long time if kept pure (two methods) • Batch Purification • In-port only • Uses heated settling tank • Continuous Purification • At-sea method • Centrifugal purifier separates oil & contaminants

  11. Propulsion Shaft • Shaft is hollow: reduces weight & increases resiliency • Consists of four sections • Thrust shaft - from thrust bearing in reduction gears to end of engineroom • Line shaft - located in shaft alley (supported by line shaft bearings) • Stern shaft - part of shaft which penetrates hull (supported by Stern Tube bearings) • Propeller shaft - shaft connected to propeller (supported by Strut Bearings)

  12. Propulsion Shaft • Different sections needed for easy installation, removal, & maintenance

  13. Propeller • Made of hub and blades & creates the thrust necessary to propel the ship through the water • Terms: • Pitch: axial distance advanced during one complete revolution of screw • Face: the pressure side • Back: the suction side

  14. Propeller Types • Constant vs. Variable Pitch • Variable has the twisted look • Adv: more efficient over wide range of speeds • Fixed vs. Controllable Pitch • In controllable, blades can rotate on hub to change pitch (change direction) • Right vs. Left Hand Screw • Viewed from aft of ship • Twin-screw ships have one of each

  15. CRP System

  16. Propeller • Cavitation • Formation and subsequent collapse of bubbles as propeller turns • Occurs at critical speed • Effects • Excessive noise • Erosion of blades • Decreased efficiency

  17. Propeller Power vs. Shaft RPM • Flow a RPM; Thrust (head) a RPM2; Power a RPM3 • So, if 10% power yields 100 RPM, how much power will produce 200 RPM? 10% x% 1003 2003 x = 10 * (200/100)3 = 80% power

  18. Sample Problems • Shaft hP • shp=2πNT/33,000 • Effective hP • Propulsive efficiency • Slip ratio

  19. Questions?

More Related