Presentation is loading. Please wait.

Presentation is loading. Please wait.

Propulsion Train & Shaft Line Components Introduction Reduction Gears - fast to slow Lubrication System - overcome friction Shaft components - turbines.

Similar presentations


Presentation on theme: "Propulsion Train & Shaft Line Components Introduction Reduction Gears - fast to slow Lubrication System - overcome friction Shaft components - turbines."— Presentation transcript:

1

2 Propulsion Train & Shaft Line Components

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

4 Reduction Gears Purposes – Allow turbine and propeller to operate at most efficient speeds – Combine two turbines to common shaft

5 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

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

7 Reduction Gears Locked Train 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

8 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)

9 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

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

11 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

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

13 Propulsion Shaft Different sections needed for easy installation, removal, & maintenance

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

15 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

16 CRP System

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

18

19 Propeller Power vs. Shaft RPM Flow  RPM; Thrust (head)  RPM 2 ; Power  RPM 3 So, if 10% power yields 100 RPM, how much power will produce 200 RPM? 10% x% 100 3 200 3 x = 10 * (200/100) 3 80% power = 80% power

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

21 Questions?


Download ppt "Propulsion Train & Shaft Line Components Introduction Reduction Gears - fast to slow Lubrication System - overcome friction Shaft components - turbines."

Similar presentations


Ads by Google