1. WATER COOLING SYSTEM

2. 1.HEAT SOURCES  Burning of fuel  Heat developed by compression of air  Frictional heat

3. 1.HEAT SOURCES  Burning of fuel  Heat developed by compression of air  Frictional heat 2. HEAT DISTRIBUTION  1/3 = converted into useful work ( transferred into mechanical energy / BHP.  1/3 = lost as exhaust gases  1/3 = lost for cooling / absorbed by metallic walls of the combustion chamber.

4. 1.HEAT SOURCES  Burning of fuel  Heat developed by compression of air  Frictional heat 2. HEAT DISTRIBUTION  1/3 = converted into useful work ( transferred into mechanical energy / BHP.  1/3 = lost as exhaust gases  1/3 = lost for cooling / absorbed by metallic walls of the combustion chamber. 3. OVERHEATING  Breakdown of L.O. film  Loss in material strenght  Excessive stresses due to unequal temperatures  Faliure to maintain proper clearances between running parts.

5. 4. COOLANTS  Fresh water  Luboil

6. 4. COOLANTS  Fresh water  Luboil 5. COOLING WATER TEMPERATURE 5.1 The temperature should be kept as high as possible. 5.2 If to high, it will cause boiling of water and formation of scale deposits ( incrustration ) 5.3 If to low, it will lead to condensation of combustion gases on the liner surfaces. 5.3.1 Product of condensation may:  contain acids causing corrosion  cause so called cold sludge in the L.O. increasing wear in all moving parts

7. 6. COOLING WATER TREATMENT & CONSEQUENCES  If the cooling water is not properly treated, the closed cooling systems may undergo fouling, formation of deposits ( preventing or disturbing the heat transfer ). The deposit consists of loose sludge and solid particles.  Removal: mechanically ( first brushed or rinsed off with water ) or chemically.  Narrow spaces are chemically cleaned.  Limestone deposits can be cleaned with acid solution.

8. 6. COOLING WATER TREATMENT & CONSEQUENCES  If the cooling water is not properly treated, the closed cooling systems may undergo fouling, formation of deposits ( preventing or disturbing the heat transfer ). The deposit consists of loose sludge and solid particles.  Removal: mechanically ( first brushed or rinsed off with water ) or chemically.  Narrow spaces are chemically cleaned.  Limestone deposits can be cleaned with acid solution. 7. WATER COOLING SYSTEMS  Large slow speed, two stroke engines have 2 separate closed cooling circuits.  A header or expansion tank allows venting of the system. The header has connections from engine discharge & pump suction line.  A heater is fitted with by pass to warm the engine when necessary.

9.  Cylinder jacket system Water → lower end of the jacket → cylinder cover → exhaust valve cages → turbocharger → turbine cooling spaces → air separator → main discharge.  The piston cooling system Water → piston cooling tank → piston water cooler → piston cooling connections → return by gravity to supply tank