众文网1.我是交通运输专业,求一篇铁路相关的英文文献及其中文翻译,英文
Summary: How to obtain good sound comfort on trains？总结：如何获得良好的列车声音舒适度？
SPL 65-70 dBA
Acoustically well designed vehicle / 声学上设计良好的车辆
No rattling noise from interiors / 内装无噪音
Fasten interiors properly (dampers can be used) / 内装件安装牢固（可采用减震器）
Avoid tonal noise from fans or drive system / 避免传动系统风机的音调噪音
Acoustically optimized and vibration isolated auxiliary and drive systems / 声学上经过优化的和振动隔离的辅助及传动系统
High frequencies > ~2 kHz shall be very well damped / > ~2 kHz的高频噪音应得到较好的吸收
Increased absorption in compartment / 客室内增强了振动吸收
Privacy in vehicle throughout journey / 旅途中车辆的私密性
Use of HVAC system as a masking sound at standstill / 列车静止时运转HVAC系统作为掩蔽声
这是一篇关于车辆降噪的，可以吗？
2.离心泵叶轮 英文文献 5000字左右
Centrifugal is the inertia of the body, such as water droplets on the umbrella, when umbrellas slow rotation, water droplets will follow an umbrella rotation, this is because the umbrella and the centripetal force of friction as drops of water drops. But if an umbrella rotation speed up, the friction force is not enough to keep the water in circular motion, then drops out of the umbrella to the outer movements, like stones do a rope with circular motion, if the speed is too fast, rope breaks, stones will fly out. This is the so-called centrifugal. Basic structure of centrifugal pump is made up of six parts, namely: impeller, pump, pump shafts, bearings, sealing rings, stuffing. 1, the core part of the impellers are centrifugal pumps, its speed and high output power, impeller blades also played a major role, in front of the Assembly to pass the static balance of impeller experiment. Requirement inside and outside the surface smooth of the impeller to reduce flow friction loss. 2 also known as a pump, pump body, it is the body of the pump. Play a role in supporting fixed, and bays of the housings connected. 3, the role of pump shaft is connected take coupling and electric motor, the motor's torque to the impeller, it is the main part of transferring mechanical energy. 4, bearing is set on the pump shaft support component of the pump shaft, roller bearing and bearing two. Rolling bearing using butter as a lubricant oil to appropriate for the General volume of the 2/3~3/4 too much heat, too little and the noise and fever! Use of sliding bearings are transparent oils for lubricants, refueling to the oil line. Too much oil to pump seeping loss and bleaching, accidents caused by too little bearing overheating burned again! Bearing temperature in water pump is running at 85 ℃ General running at about 60 degrees, if high will find reason (whether there are impurities, oil is dark, water) and processing in a timely manner! 5, seal rings also known as a reduced ring. Clearance between the impeller inlet and pumping shells causing water pump of high pressure area in the General Assembly through this gap flow to the area of low pressure, affect the pump out of water, efficiency! Gap too small can cause friction and wear of impeller and pump shell. In order to increase return resistance decrease leakage, delay the service life of impeller and pump shell, foreign aid and impeller in the pump case is equipped with sealing ring, sealing gaps remain between the 0.25~1.10MM. 6, stuffing mainly by fillers, water seal rings, packing, product packing gland, a water pipe. Stuffing box of the role is mainly to close gaps between the pump and pump axle, do not let the water flow in pump to the outside to do not let outside air into the pump. Always keep a water pump in the vacuum! When the pump shaft and packing friction generates heat by water cooling tube-sealing water injection water circle makes packing! Maintain the normal operation of the pump. So in the pump runs during the inspection tour is special attention should be paid to the stuffing box of checks! Runs about 600 hours to replace the filler. 7 during the operation in centrifugal pumps, axial thrust balancing device, because the liquid is in low-voltage into the impeller, and outflow at high pressure, the pressure on both sides of the impeller, axial thrust of a link to the entry, will cause rotor axial moving, wear and vibrations, so you should set the axial thrust bearing, to balanced axial force.The working principle of centrifugal pump is: centrifugal pump has been able to send water out is due to the effects of centrifugal force. Water pump in front of the work, of pumps and water intake pipe must be tank filled with water to form a vacuum, when the rapid rotation of the impeller, leaf water fast rotation, rotate the water flew from the impeller in centrifugal force, pump after being thrown in the water, central part of the formation of the impeller vacuum region. Sources of water in the atmospheric pressure (or pressure) through the pipe network pressure under the action of the intake tube. This loop, you can achieve continuous pumping. This is worth mentioning: certain before the start of centrifugal pump to the pump after the shell is filled with water, can be started, otherwise the body will not complete the liquid absorption, cause of pump body heat, vibration, no water, "idle", damage to the pump ("gas up") creates the equipment accident.Many types of centrifugal pump, classification methods there are several common mode 1 by inhalation of the impeller: single-suction centrifugal pumps-double-suction centrifugal pump. 2 press the number of impeller: single stage centrifugal pump of multistage 。
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