1. What is a ship piping system? What kinds of piping systems are there?
Answer: Ship pipeline system is the general name of pipelines, mechanical equipment and testing instruments specially used by ships to transport and discharge liquids or gases in order to complete certain tasks, and is usually referred to as ship pipeline system for short. Ship pipelines are divided into power pipelines and ship systems. The power pipeline includes: a fuel pipeline; Lubricating oil pipeline; Cooling pipe; Compressed air pipeline; Exhaust pipe Ship system can be divided into: bilge water system; Ballast water system; Fire fighting system; Ventilation system; Water supply system; Refrigeration and air conditioning system; Cargo oil system, etc.
2. What are the quality indicators of fuel?
Answer: The quality indicators of fuel are: cetane number; Density; Viscosity; Freezing point, cloud point and pour point; Mechanical impurities and moisture; Calorific value; flash(ing) point
3. Draw a picture to illustrate the function of fuel pipeline.
Draw a picture to illustrate the structural characteristics of the daily fuel tank.
5. On the basis of theoretical calculation, what other factors should be considered in the total volume of oil tanks?
Answer: the volume coefficient Cr 1. 1~ 1.2, the reserve coefficient Cc 1. 1, and the wind wave coefficient Cf 1.05~ 1.2.
6. Briefly describe the requirements of ship design for fuel pipeline.
Answer: 1 cabinets should be connected by pipes, and there should be stop valves on the pipes to ensure normal oil supply when the ship inclines. Large and medium-sized ships are equipped with independently driven oil pumps, and small ships are equipped with hand pumps to ensure continuous oil supply. Stop valves or cocks on the oil supply pipelines of each oil tank should be directly installed on the tank wall, and quick-closing valves should be installed on the outlet pipelines of daily-use oil tanks of deep oil tanks, so that they can be quickly closed outside in case of fire or crisis. 4 The fuel pipeline must be isolated from other pipelines and shall not be arranged on high temperature or electrical equipment. 5. Sedimentation tanks and fuel tanks or daily oil tanks specially equipped with sedimentation tanks shall be equipped with self-closing drain valves or cocks. Large ships burning two kinds of fuels should be equipped with two sets of oil supply pipelines and a fuel oil return collection cylinder to collect oil return, which can be used for mixing and replacing two kinds of fuels.
7. Briefly describe the function, composition and types of oil pipelines.
A: Function: The lubricating oil pipeline system provides enough lubricating oil that meets the quality requirements for marine power plant equipment such as diesel engines and superchargers, so as to ensure that the relevant friction pairs are in a good lubrication state, avoid dry friction, and take away some heat during lubrication, thus playing a certain cooling role. Composition: Lubricating oil pipeline system generally consists of lubricating oil storage tank, Huayou circulating tank, lubricating oil pump, purification equipment and lubricating oil cooler. Type: Lubricating oil pipeline system can be divided into wet bottom shell type and dry bottom shell type according to the structural type of diesel engine.
8. Briefly describe the requirements of ship design for oil pipelines.
Answer: 1 The layout of lubricating oil pipeline system should maintain reliable oil supply within a certain range of ship's pitch and pitch. 2 Layout of lubricating oil circulating pump The length of suction pipe should be as short as possible, so the oil pump should be as close as possible to diesel engine or circulating oil tank. In order to reduce pipeline resistance and pipeline vibration, the number of elbows in the pipeline from lubricating oil circulating pump to filter should be as small as possible, and the length of the pipeline should be shortened. The oil filter is generally arranged in front of the oil cooler, and pressure gauges should be installed before and after the filter, and a low-pressure alarm is also mapped in the pipeline. 5. The lubricating oil storage tank should be close to the deck oil inlet and have a certain height, so as to replenish lubricating oil to the circulation tank or enter the barge pump by gravity. 6 If the supercharger adopts forced circulation pressure lubrication, a supercharger lubricating oil gravity box is set as an emergency, and the height of the gravity box must be about 12m above the supercharger axis.
9. Briefly describe the functions and forms of cooling pipes.
Answer: Function: It is to provide enough fresh water, river water, seawater or cooling oil for the main and auxiliary diesel engines, main and auxiliary oil coolers, fresh water coolers and other heat exchangers, gear boxes, bearings, tail shaft pipes in shafting and other equipment that need heat dissipation, so as to ensure their reliable operation within a certain temperature range. Form: open cooling pipe and closed cooling pipe.
10. Draw a picture to illustrate the principle and characteristics of open cooling pipes.
Answer: Principle: The seawater pump 4 sends seawater from the submarine gate 1 to the temperature regulator 5 through the seawater valve 2 and the filter 3, and then enters the oil cooler and the main engine cooling related components, and then collects in the main pipeline, and then pushes the one-way valve to be discharged overboard. The temperature regulator automatically regulates the flow of cooling water, so that the oil temperature and water temperature entering the diesel engine are within the allowable range. Features: few open cooling pipes, simple pipes, convenient maintenance and abundant water sources. However, the quality of cooling water is poor, and impurities cause blockage or adhesion on the cooling surface, or corrode the metal wall, which makes the heat transfer condition worse and damages the metal wall due to overheating; The outboard water temperature changes greatly, which is directly affected by seasons and regions, and the change range is large, which is not conducive to entering the diesel engine for cooling. It is only suitable for cooling small diesel engines and various heat exchangers, air compressors, exhaust pipes and tail shafts. The requirements for cooling water are not strict.
1 1. Draw a picture to explain the principle and characteristics of closed cooling pipes.
Answer: Principle: Fresh water pump 1 sucks fresh water from fresh water cooler 8, enters diesel engine 3 to cool high-temperature components, and then returns to fresh water cooler 8 for closed cycle. Seawater circulates in an open way, but the pipeline includes a fresh water cooler. Features: The fresh water quality is good, which will not cause channel blockage and salting-out, with less scaling, and it is easy to control the inlet and outlet temperatures of diesel engines. However, this kind of pipeline is widely used in large and medium-sized ships because of its many equipment, complicated pipeline and inconvenient maintenance and management.
12. Briefly describe the function of expansion tank.
Answer: An expansion tank is set in the closed cooling pipeline to adapt to the volume change of fresh water in the pipeline with temperature change; The exhaust pipe is connected to the upper part of the expansion tank at the highest position of the diesel engine, so that the gas separated from fresh water escapes to the atmosphere; The expansion tank is placed at a certain height above the suction inlet of the fresh water pump to keep the suction pipeline at a certain water pressure to prevent vaporization; It's like replenishing fresh water in a pipeline.
13. Why do ships have high and low subsea doors? What are the requirements?
A: There are at least two submarine doors in the engine room of the ship, which are arranged on the left and right sides of the ship respectively. The low diving door is located at the bottom of the engine room and the high diving door is located at the stern. For the stern engine room of large ships, the submarine door should be arranged in the front of the engine room as far as possible to avoid inhaling air and sewage. The underwater gate should be provided with a grid or orifice plate to prevent larger sludge impurities from entering the seawater pipeline. Seawater tanks should be equipped with ventilation pipes, compressed air pipes and steam pipes to blow away dirt and ice particles.
14. What are the characteristics of submarine gate structure?
15. What are the requirements for the temperature of cooling water entering and leaving the diesel engine? Why?
16. Draw a picture to illustrate the function of the thermostat.
17. Briefly describe the requirements for cooling pipes in ship design.
Answer: 1 There are at least two submarine doors in the engine room of the ship, which are respectively arranged on the left and right sides of the ship. The low underwater door is located at the bottom of the engine room and the high underwater door is located at the stern. 2. Underwater doors should be equipped with grids or orifice plates to prevent large sludge impurities from entering seawater pipelines. Seawater tanks should be equipped with ventilation pipes, compressed air pipes and steam pipes to blow away dirt and ice particles. The drainage pipe for discharging used sewage is usually arranged behind the submarine door or suction port, as far away as possible. In addition to the main engine's own water pump, there must be an independently driven standby pump, and small ships can be replaced by other pumps with sufficient displacement. The bottom layout of seawater pipeline should meet the requirements of bottom pressure and temperature parameters of various equipment, and strive for low equipment energy, short pipeline and convenient operation and maintenance. 6 When closed cooling is used, each main engine should have an independent closed cooling pipeline, and a connecting pipe should be set between seawater pipeline and fresh water pipeline. There is a cut-off valve in the middle. When the pipeline of the closed cooler fails, it can be directly cooled, and seawater can be used for cooling. When ships sailing in the ocean are directly cooled by seawater, anti-corrosion measures such as inserting zinc rods into the cooling water jacket must be taken.
18. What are the uses of compressed air on board?
Answer: Starting, reversing and control of diesel engine; Clutch and gearbox control; The pressure cabinet is inflated (fresh water, seawater); Purge underwater doors, residual oil tanks, etc. ; Whistles and fog whistles roar; Energy source of remote control and automatic control system; Drive the injection of extinguishing agent; Miscellaneous purposes, pneumatic tools, etc. Fire weapons from warships.
19. What accessories are there on the air bottle? What are their respective roles?
Answer: 1 air bottle: used to store compressed air for standby, start air bottle, whistle air bottle, sundries air bottle, etc. 2 air compressor: used to start the main engine, generally there are two, one of which is driven by power other than the main engine; 3 steam-water separator; 4 air pressure reducing valve; Safety valve: automatically open when the working pressure exceeds the specified value, and automatically close after the pressure is restored to protect the pipeline and equipment.
20. Briefly describe the requirements of ship design for compressed air pipeline.
Answer: The 1 main engine started by compressed air pipeline must have an independent air compressor. Air bottles can be placed vertically or horizontally, usually in the solid parts of the hull structure. Gas-water separator should be installed on the pipeline where the air compressor inflates the gas cylinder. Pressure gauges and safety valves shall be installed on the outlet pipelines of air compressors, gas cylinders, coolers and pressure reducing valves. 4 compressed air pipeline generally adopts centralized gas supply.
2 1. Briefly describe the working principle of gas-water separator.
Answer: The air discharged from the air compressor enters between the two filter plates through the elbow, then passes through the filter plates and is sent to the air bottle through the outlet elbow 3. By sharply changing the direction of air flow, oil-water particles drop into the bottom of the separator due to their inertial collision and are regularly discharged through the part 6.
22. What is the function of the exhaust pipe? How many forms are there?
Answer: The function of the exhaust pipe is to discharge the exhaust gas from the main and auxiliary diesel engines and auxiliary boilers to the atmosphere outside the engine room, so as to keep the engine room in a good environment. In addition, we should also consider reducing exhaust noise and using waste heat to meet special requirements (extinguishing sparks in exhaust gas). The exhaust forms of diesel engines are water exhaust and underwater exhaust. Underwater exhaust is widely used in military ships. Form: 1 Exhaust gas from diesel engine is directly discharged into the atmosphere through exhaust pipe and muffler; Install a thermal expansion compensator between the muffler and the diesel engine gas collector to compensate the pipeline deformation caused by the heating of the exhaust pipeline; The pipeline is equipped with an exhaust gas boiler, and the exhaust gas of the diesel engine is discharged into the atmosphere through the expansion joint and the exhaust gas boiler; 4. In the form of the above 3, the bypass pipeline is not equipped with a muffler; 5 In the above form 3, the exhaust gas boiler is replaced by an exhaust gas-oil mixed boiler, and the steam output of the boiler is controlled by an exhaust gas regulating valve.
23. What are the characteristics of the layout design of bilge water system?
Answer: The pipeline system at the bottom of the whole cabin should be arranged according to the characteristics and safety requirements of the ship to ensure the effective pumping of bilge water. The pipeline layout shall ensure that when the ship floats or inclines to no more than 5 to any side, it can discharge the accumulated water in the bilge, and it is not allowed for outboard water or water in any water tank to enter the cabin through this system. Therefore, in the pipeline of bilge water, only one-way flow of water is allowed, which means "only getting out but not getting in".
24. What requirements should the bilge oil-water separator meet?
Answer: Bilge water contains a lot of dirty oil, which will pollute navigation waters and ports if it is directly discharged overboard, so a bilge oil-water separator must be installed. Marine bilge oil-water separator meets the following requirements: bilge water should meet the specified discharge standards after treatment; It can still work normally at an inclination angle of 15 degrees; Can automatically discharge oil; Simple structure, small volume, light weight and easy maintenance.
25. What are the main functions of the ballast system?
Answer: The function of ballast water pipeline system is to inject or discharge pressure into ballast water tank.
Carrying water to achieve: maintaining proper displacement, draft and longitudinal and lateral balance of the hull; Maintain an appropriate metacentric height; Reduce excessive bending moment and shear force; The purpose of reducing hull vibration.
26. What are the characteristics of the layout design of ballast system?
Answer: The ballast water pipeline system requires 1) that the flow of ballast water in the pipeline is "something goes in and something goes out". That is to say, the ballast water is injected into the ballast water tank through the same pipeline and then discharged from the ballast water tank. Therefore, it is not possible to set a check valve in the pipeline system, but to adjust the connection through the stop valve box. 2) On large ships, in order to prevent seawater from leaking from the ballast water pipe to the cargo hold, the ballast water pipe is laid in the pipe gallery in the center of the double bottom tank. The arrangement of suction ports in each tank should be helpful to the discharge of ballast water. 3) When the ballast water pipes in the forepeak cabin and the stern cabin pass through the forepeak cabin and the stern cabin, it is better to have gate valves that can be opened and closed on the upper deck, so as to immediately close the gate valves when the fore and aft parts of the hull are damaged, and prevent outboard water from entering the ballast water system. Layout: branch pipe type, main pipe type and pipe tunnel type.
27. How to calculate the volume of fresh water pressure tank?
Answer: The volume of the fresh water pressure tank is related to the water consumption, and it is the sum of the minimum compressed air volume V 1, the effective volume V2 and the ineffective volume (dead volume) V3. Therefore, before determining the volume of the fresh water pressure tank, it is necessary to calculate V 1V2V3.
28. How to determine the pipe diameter of the pipeline system? What factors are related to it?
Answer: The pipe diameter is determined according to the energy loss of the fluid flowing through the pipeline. When the flow rate is constant, the pipe diameter mainly depends on the flow rate of the fluid in the pipe. Influencing factors: volume flow of fluid, velocity of fluid in pipeline, mass flow of fluid and density of fluid.
29. Generally speaking, what requirements should the layout of pipelines meet?
Answer: Pipeline layout should not only consider the relative position of mechanical equipment, pipelines and their accessories in each pipeline system, but also handle the relationship between pipelines, pipelines and other mechanical equipment and the hull. In pipeline design and layout, the requirements of slow engine room layout and the working characteristics of pipeline equipment should be fully considered to ensure the reliable, convenient and economical operation of the whole power station. Reliability, operability and economy.
Chapter VI Design of Ship Power Plant
1. What are the stages of ship design? Draw its flow chart.
Answer: Preliminary design, detailed design, production design and completion document preparation.
2. Briefly explain the main contents of the marine power plant in the technical task book.
Answer: Main engine model, transmission mode, navigation area and endurance, fuel consumption or energy saving requirements, number and power of generators, over-familiar driving mode and requirements for automation and remote control of power cabin, number of deck machinery and power of ventilation, air conditioning and refrigeration equipment, etc.
3. What are the main factors that determine the position of the engine room?
Answer: 1. Requirements for general layout planning of ships; Second, the requirements of the power plant itself.
4. What are the forms of engine room layout? Compare its characteristics.
Answer: When the engine room is located in the middle, the advantage is that there will be no or little pitching when the ship is full or empty. The disadvantage is that the volume of cargo hold is reduced and the efficiency of shafting is reduced. When the engine room is located in the rear, it has the advantages of shortening the length of the transmission shaft system, reducing the construction cost and simplifying the maintenance work. The disadvantage is that it will produce a large trim when it is fully loaded or unloaded.
5. Briefly describe the principles and requirements of engine room layout.
Answer: 1 tilt and swing 2 balance and center of gravity 3 relative position between mechanical equipment 4 operation management and maintenance
6. Briefly describe the estimation method of ship power station load.
Answer: The demand coefficient method, the empirical formula method of statistical regression and the three-type load method, among which the three-type load method is more accurate.
7. The role of marine boilers
8. What are the main contents of ship power plant design? This paper discusses the present situation and development trend of marine power plant from three aspects: design angle, design method and evaluation requirements.
Answer: The main contents of marine power plant design are reliability, maneuverability and economy, vibration and noise of auxiliary boilers and power stations.