ĐỀ CƯƠNG TRANG TRÍ

ĐỀ CƯƠNG TRANG TRÍ Question 1:state concept and function of main propulsion plant equipment of Marine propulsion plant? • Concept: MMP equipment os a system of equipment that undertake speed and direction of ship • Function: - Main engine: generates mechanical energy to turn a ship’s propeller - Propulsion equipment: transforms mechanical energy of the main engine into thrust force when maneuvering - Driving equipment: it is intermediate equipment to transmit power from a main engine to a screw propeller It consist of: shafting,flanges, split muff coupling,clutch and reduction gear - Main boiler: its duty is to supply steam with high pressure and temperature to steam engine, steam turbine and other auxiliary machinery - Conveyance equipment: they are used to convey working substance to a main engine Question 2: state concept and function of auxiliary equipment of marine propulsion plant? • Concept : it supports the main propulsion plant equipment and other operations of a ship • Function: - Generator: its duty is to supply electric energy for the ship to serve many different objects, such as: illuminating loading and unloading cargoes and all other electric equipment - Compressed air system: it generates and stores compressed air with high pressure for starting and reversing the main engine, starting generators engine, cleaning parts of the engine It is also used in remote control and automatic control systems Auxiliary boiler: it supplyes steam to heat fuel,water, diesel engine( before starting) and cabins It also serves steam chanineries and equipment Question3: state the technical characteristics of steam turbine propulsion plant? - In the diesel engine propulsion plant, working substance is combustion product of air-fuel mixing formed in engine combustion chamber - Thermal efficiency is high while specific fuel consumption is low - Output is not continuously generated It should be provided with air and gas distributors suitable for suction and exhaust cycles of the main engine - When working, diesel engines generate reciprocating forces and inertial moments These inertial force and moments vibration body of engine and ship’s hull The balance of a diesel engine is depended on weight of the engine moving parts, number of cylinders and suitable arrangement of cranks - Engine parts withstand also the forces that vary cyclically These characteristic limit an increase in power and revolution of main engine - Immediate pressures and temperatures in the engine combustion chamber are very high, the engine parts have to work in high temperature and friction condition so the longevity of diesel engines are reduced - Moving rule of the pistons independ on direction of crankshaft so rotation direction of diesel engines can be easily reversed by change work order of starting mechanism - In light load conditions, diesel engine are not working economically and stably - It is flexible because of short time for starting - Heat energy go out of the engine with high temperature so we can reused Question 4: state the technical characteristics of steam turbine propulsion plant? - Working substance is high-pressure steam generated in main boiler - Output is continuous, therefore can increase revolution and power, reduce weight of turbine-steam flows continuous through turbine so rotating moment, heat and mechanical load are stable Therefore turbine has a high longevity - When working, turbine does not generate inertial forces - Turbine can generate large power - Turbine can not reverse ifself - To reverse direction of the ship, it should be provided with astern turbine - Turbine’s revolution is much higher than optimum range of propeller’s revolution, so it should be provided with reduction gear - Efficiency of the system is low because it lost of energy, efficiency about 22-26% - The propulsion plant is very dangerous as steam have high pressure and temperature It may cause danger to operators when emergency happens - It requires high quality of water in the system - It takes a long time to prepare for starting the system, so it’s not flexible Question 5: state requirement about the weight of propulsion plant for independent working ability of the ship - Total weight or displacement of the ship consist of four main component - + weight of hull,of propulsion plant, of needment and of cargoes - With a certain ship, one of the weight increases, then other component has to reduce If the weight of propulsion plant is increased then the cargoes transportation and the independent working ability of the ship is reduced So application methods to reduce the weight of propulsion plant are necessary - In fact, the ships have the same displacement but speed and power are varied, so then the weight of propulsion plant is varied In the other hand, with the same power but the weight of propulsion plant is also varied when type of propulsion plant is different Therefore, the definition of relative weight is used: + K=W/D ( with W is total weight of propulsion plant) Question 6: state requirement about dimension of the engine room - Alomost machinery is installed in the engine room So, the dimension of the engine room has to suit to all of the machinery and the equipment installed in to it Besides, it must be convenient for maintaining, repairing and safe for operating the machinery of the propulsion plant - To satisfy these requirement, the engine room is as large as possible In the other hand, if the engine room is too large, cargo holds space is reduced and it reduces the cargo transportation ability of the ship Therefore the dimension of the engine room should be calculated to satisfy the both requirements - To perform the requirement about dimension of the engine room, the definition “saturated coefficient” are used Area saturated coefficient of the engine room: the number of horsepower of the propulsion plant on unit of the engine room are Kn=∑N /S - Volume saturated coefficient of the engine room: the number of horse power of the propulsion plant in unit of the engine room space Kv=∑Ne/V Where:-∑Ne: total power of the propulsion plant - S: total area of the engine room floors - V:total volume of the engine room space Question 7: state requirement about the needments of the propulsion plant - For the MPP,main needment is fuel The more amount of fuel stored on the ship, the higher the independent working ability is However, weight of the fuel stored is also component of the displacement, if the fuel stored is too much then transportation ability of the ship will be reduced So the fuel stored should be calculated suitably with power, specific fuel consumption of the propulsion plant, the times on voyage operation area of the ship to raise the transportation ability - The fuel stored can be calculated according to the fuel consumption in all times of an independent voyage: ∑B=∑Ne.gtb.t Where:+ ∑B: Amount of the fuel consumption in all times of the voyage + ∑Ne: Total power of the propulsion plant +gtb: Average specific fuel consumption of the propulsion plant +t: the times of the independent voyage - Question8: describe structure of single acting arrangement,principle of installation,designing of the shaft? There os one or more shaft line depending on kind of ship In almost cargo ships, the shafting has only one propeller and one shaft line is used Normally, a shaft line is placed parallelly with the keel of the ship, in some case the shaft line is placed unparallelly with the keel It makes with basic line an angle α, α