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船舶-水下测试

船舶-水下测试
船舶-水下测试

Measurement 24(1998)43–54

Vibration measurements on blades of a naval propeller rotating in

water with tracking laser vibrometer

P.Castellini,C.Santolini

Department of Mechanics,University of Ancona,via Brecce Bianche,I-60131Ancona,Italy

Abstract

The application of laser Doppler vibration measurements is a powerful technique for monitoring and analysing mechanical systems.Frequently experiments in operative conditions may be a useful tool for analysing the real behaviour of an object.However,in several applications we may ?nd that the object is rotating during its work and in these conditions the measurement with traditional techniques becomes di ?cult.For these reasons a system for the tracking of rotating objects has been developed in order to perform vibration measurements.

In the present work the application of the tracking laser scanning vibrometer on an operative condition problem is shown.A tracking laser scanning vibrometer has been used for measuring the vibration of a map of points on the object surface during a complete circular motion.The analysed object was a model of a naval propeller working in water.A comparison has been found with the static analysis,in water and air,of the same propeller.Some results are shown.?1998Elsevier Science Ltd.All rights reserved.

Keywords:Laser vibrometry;Naval propeller;Rotating machinery;Speckle noise

1.Introduction

vibration can play an important role in preventing failures due to fatigue.The resolution of this kind of problem is of signi?cant economic importance,In machinery,the continuous trend is to generate more power per pound of equipment with a lower linked to the availability and service life of such equipment [1].

consumption.In recent years,the interest of the mechanical engineer has been oriented towards the In mechanical applications,the rotating machinery represents a large part of interest in development of devices with reduced acoustic emis-sions for low acoustic pollution.In order to obtain mechanical systems.The rotating ‘‘disk’’is a fun-damental component of modern rotating these results,the machines must work with closer tolerances at higher speeds.

machinery:a disk is a good model of many di ?erent elements of complex systems such as Another important task for the researcher is to improve the reliability of machines.This study magnetic and optical computer memory units,automotive components,propellers,fans,etc.In determines the need for control of static and dynamic deformation of moving parts,i.e.analysis the case of naval propellers,the problems are also correlated to the behaviour of water where high of the vibration behaviour of the machine in operative conditions.In a number of cases,compo-variation of pressure is induced.Cavitation is a very important problem a ?ecting the reliability nent failures are caused principally by vibration-related fatigue stresses.Monitoring of component and acoustic emission of propulsion systems in

0263-2241/98/$–see front matter ?1998Elsevier Science Ltd.All rights reserved.PII:S0263-2241(98)00044-X

44P.Castellini,C.Santolini/Measurement24(1998)43–54

civil and military ships,where comfort and Another type of vibration is that induced by ‘‘stealth’’capabilities are respectively requested.

clearance,i.e.a reduced space between the hull Several important sources of vibration transmit-and the propeller.This problem,very evident in

hulls with heavy displacement,is due to the genera-ted to the hull are due to the propulsion system.

The propeller produces an excitation of the boat,tion of pulses by the water?ow,which is forced principally by the passage of each blade in front

to pass in a reduced space.These pulses are to sternpost and by transmission,through shaft transmitted to the poop of the hull.

and bearing,of vibration of blades.Dynamic and

Traditional contact sensors,such as accelerome-hydrodynamic e?ects,i.e.due to solid or liquid ters,are not able to resolve this kind of problem.

In fact,solid sensors alter the?uid-dynamic?eld masses,can generate vibrations.

A knowledge of the pressure?eld on blades around the object and are subjected to centrifugal could allow us to calculate the excitation forces

loads.The mass of these devices can change the on the propulsion system,and this should be very behaviour of analysed blades and their volume the important in order to analyse the vibrational

?ow around.The extraction of a signal from a behaviour of the propeller.rotating device can be di?cult,and the use of

telemetry or other techniques can be necessary.

If the e?ects of solid masses(shaft and blades)

can be scheduled and analysed through analytical In order to study the axial vibration pattern on techniques,the vibrations induced by the hydrody-

a rotating disk,two non-contact approaches can namic e?ect are very di?cult to predict.In fact,be used,the Lagrangian or the Eulerian one,i.e. the e?ects of the water are linked to the real

either with the measurement point following the position of blades with respect to the hull and moving point or with the measurement point

steady and the surface moving in front of it.In small di?erences in project parameters can induce

large problems.both cases,it is possible to extract modal informa-Hydrodynamic excitation sources are mainly the

tion on the vibrating structures.

variation of wake upstream,the cavitation and the In Reinhard et al.’s work[1],the measurement turbulence in the abaft of the propeller.The?rst

is obtained using a stationary laser interferometer is due to the non-stationary condition of?ow observing di?erent points at di?erent times.The

rotational speed can be about7000rpm,but a around the propeller.It induces low frequency

vibrations and very often a transient response of good?nishing of the surface of the analysed object the propeller due to the passage of a crest in

is requested to avoid speckle e?ects.A complex the wake.data analysis in the post-processing step is neces-Cavitation occurs when a large pressure varia-

sary to extract modal information[2]from these tion on the blade surface is present,due to the measurements when the shape of the rotating

device is complex.In any case it is not possible to high-speed water?ow,determining a separation

between water and steam or gases dissolved in extract the time history of the vibration in a single them.

point of the structure.

The abrupt variation of pressure,due to the Moreover,if laser interferometry is used,the generation and collapse of bubble clouds in the

Eulerian approach shows some problems;the‘‘in-proximity of the blade surface,induces a very plane’’component of the surface velocity generates intensive excitation at the highest frequencies.The

a very tedious noise due to the laser speckle.When separation and attachment of?ow cause a large component wavelets of an incident laser beam are variation of load at lower frequencies,too.In

dephased on scattering from an optically rough particular,when the speed of the hull is increasing,target,a speckle pattern is generated.When the the propeller cavitation can become a big problem.

target motion causes changes in the speckle pattern Vibrations are the turbulence in the abaft of the on the photodetector,the resulting noise cannot propeller,which determine a geometrical distortion

be distinguished from genuine vibration and it of the wake.The excitation obtained is in a represents a‘‘pseudo-vibration’’[3].The scattered medium range of frequency.

light pattern due to the interaction between the

P.Castellini,C.Santolini/Measurement24(1998)43–54

45 laser and the surface roughness moves while the the laser to trace a circle on the surface of the

projection.The signal generation clock is con-surfaces are moving and gives a signal which is

not correlated to the vibration,while it is corre-trolled by the pulse-train signal from the encoder. lated to rotational speed.It is not possible to

An incremental encoder measures the instantan-separate the component that hides the vibration eous angle of the shaft.The resolution in the angle signal.

determination is0.5°.

For the solution of this kind of problem,Felske The measurement and control system consists [4]and Fieldhouse and Newcomb[5]proposed

of the PC with a National Instruments AT-MIO the use of a laser Doppler interferometer,or a16E-10board.This board generates the signal to holographic interferometer,used with an image

drive the scanning mirror of the vibrometer head derotator,i.e.a device which is capable of freezing and to acquire the signal of the instantaneous the rotation of a component.A derotator is based

position of the laser beam,a reference signal and on the observation of the rotating object through the vibration signal.The signal drives the mirrors

through a closed loop control circuit,which allows a roof edge prism that is rotating at half the

angular speed of the component.This condition us to improve the dynamic response of the mirrors. makes the image of the component stationary,

CADA-X software,from LMS International,is regardless of its rotational velocity.With this also used for the modal analysis of a propeller in solution,a very complex and high-cost measure-

air and in water.

ment system is obtained.In the practical applica-

tion of this technique it is di?cult to obtain a

good alignment of di?erent components,and then 3.The test performed

the application on the?eld becomes di?cult,too.

In the work carried out by Bucher et al.[6],a The aim of the work is to perform an analysis technique for the Lagrangian approach to the

of the vibration behaviour of a propeller rotating vibration measurements of a disk is presented.The in water.In this case it is not possible to apply a measurement laser spot is steady in the disk?xed

classical modal model in order to analyse the co-ordinate system.Some analytical considerations vibration behaviour of the object,since the excita-

tion conditions do not respect the required hypoth-about the experimental results obtained are shown.

The present work shows the application of a esis of localised application of input forces.The system for the acquisition of vibration with the

movement of the blade in the water determines tracking of each rotating point[7],in a grid in the?uid-dynamical forces,varying randomly in time disk?xed co-ordinate system.The performances

for the presence of turbulence,cavitation and other of this system have been tested on a vibration forces and applied on the whole surface of the

propeller.

analysis of a model of a naval propeller rotating

in water.In the work carried out by Wu and Moslehy

[8],the possibility of obtaining some modal infor-

mation also in distributed excitation conditions is 2.The measurement system

shown.In these cases a complete modal analysis

is not possible.

Our work is divided into several steps,to decom-The measurement system consists of a Polytec

OFV050optical scanning head,an OFV3000pose the problem for more accurate analysis.The vibrometer controller and a PC(Fig.1).On the

?rst step in the analysis of propeller behaviour has vibrometer head two oscillating mirrors are been a modal analysis of steady disk in free–free mounted,used in the standard con?guration to

constraint conditions,performed both in air and obtain scanning of a steady surface over a regu-in water.The excitation is performed with an lar grid.

electrodynamic shaker driven by a narrow band In this arrangement,the mirrors are driven random noise.These results have been used in the respectively by a sine and cosine signal:this causes

following part of the work to understand better

46P.Castellini,C.Santolini/Measurement24(1998)43–54

Fig.1.Experimental set-up.

the vibratory phenomena in more complex condi-this kind of force applied in the propeller support,

since the low density of air and the reduced speed tions.The input forces,applied at a single point,

and free–free condition of constraints allow us to of rotation lower the aerodynamic excitation level. perform a classical modal analysis and to compute

The natural frequencies and the modal shapes natural frequencies and modal shapes.The e?ects obtained in rotation are comparable to the results of the presence of water are observed and the

of steady modal analysis.

virtual mass is computed.To verify the e?ects of installation of propeller The second step has been analysis with a propel-

on the shaft and stern tube and of rotation with ler rotating in air.The test has been performed known input signal,analysis of vibration using an with a rotational speed variable between0and

impact hammer and an acoustic excitation was 9rps.In fact,the naval propeller employed in the performed.The?rst is a traditional procedure for

structure excitation in modal analysis of a steady research is working at a speed lower than10rps

and higher frequencies are not of interest in this structure.This is a powerful technique because it application.This test has been carried out in order

allows us to put structures with a well-known to verify the capabilities of the tracking system to input force in vibration,but shows some limitation follow each point of the disk?xed grid.The results

in rotating propeller application.In fact,it is have shown the good capabilities of the system to possible to operate with this technique when the

speed is only about a few revolutions per second. analyse the vibration of the propeller during a

rotation.This analysis has also been performed to On the other hand,the acoustic excitation does determine and eliminate the e?ects of the mechan-

not allow us to know the excitation level and to ical excitation due to the shaft support,the bearing,measure the frequency transfer functions,but it the motor and the transmission device.In this case

allows us to directly excite the blades during high-the vibration of the propeller is induced only by speed rotation,too.With acoustic excitation it is

47

P.Castellini,C.Santolini/Measurement24(1998)43–54

possible to analyse the behaviour of the system at access for laser acquisition with the test bench the highest frequency,where forces generated by

shown in Fig.1.

the rotation do not give enough energy.When water is present,there are several prob-The excitation has been performed with an

lems in obtaining good measurements.The?rst impact hammer with23g mass and with a loud-problem is due to the refraction index of water. speaker of about40W power driven by a narrow

Therefore it is necessary to correct the velocity band white noise signal between800and1000Hz.data and to adapt the grid directly on the blades In Fig.2the comparison between FRFs

in the experimental set-up.The laser beam,in fact, obtained by impact hammer excitation when the is deviated in each interface between the transmis-propeller is steady and when it is rotating at1rps

sion materials on the optical path.Then,during is shown.The low speed of rotation does not the rotation,the angles between the laser beam induce variations in the behaviour of the structure

and the Perspex surface do not change and no because the test is performed in air and the centrif-other adjustment is necessary.

ugal forces are very low.Therefore,the good

The second problem is related to the formation correspondence of FRFs and in particular of of gas bubbles in water.The low head over the coherence functions shows a good capability of

propeller facilitates the cavitation and the absorp-the tracking system to perform measurements also tion of air from the surface,also with low rota-in operative conditions.

tional speed.This phenomenon and the high level In Fig.3the comparison between some results of turbulence determine the formation of bubbles obtained with acoustic excitation of a propeller

of gas around the blade surface.When the beam rotating at9rps is shown.In these tests the798Hz meets a bubble,it is deviated and,for some peak is excited in the modal analysis:in operating

instants,the measurement is not possible on the conditions,the higher sti?ness of the system analysed surface.The solution in order to avoid increases the natural frequency of the propeller.

this problem at the desired speed is to perform a Finally,the measurement has been performed large number of triggered averages(about40in in operative conditions:the propeller is rotating in

the present tests)in the power spectrum signal, water in a tank of Perspex in order to allow optical which cancel the e?ects of signal spikes.

https://www.doczj.com/doc/d76639380.html,parison between FRF obtained with impact hammer excitation on blade1:(a)propeller steady;(b)propeller rotating at1rps.

48P.Castellini,C.Santolini/Measurement24(1998)43–54

https://www.doczj.com/doc/d76639380.html,parison between FRF obtained with acoustic excitation.

The last problem is due to absorption of the reduce the gain and the resolution of the acquisi-

tion system and makes the observation of low light due to the presence of particles and impurities

in water.In our case,the good quality of water amplitude vibrations di?cult.

and the short distance in water allow very little

This e?ect is shown in Figs.5and6,obtained signal decay.in di?erent alignment conditions.In the vibration

map,obtained with shaft rotating in water at a

speed of9rps,it is possible to see the typical 4.Discussion and conclusion

pattern of a rigid oscillation at the rotation

frequency.The‘‘steady’’misalignment in the laser In the measurements performed,the main prob-

co-ordinate system is observed,in the disk-?xed lem observed is the misalignment between rota-co-ordinate system,as a‘‘dynamic’’?exion, tional axis and laser vibrometer,as shown in

because the measuring spot is travelling between Fig.4.In fact,this causes,during one turn of the points at di?erent distances from the propeller,a variation of the optical path from the

interferometer.

laser head.This is mistakenly understood as a In order to measure the vibration of the surface,

it is necessary to align the scanning head axis with ‘‘vibration’’of the surface,and then a sinusoidal

signal is detected with a frequency equal to the the rotational axis.The e?ect observed is a spuri-rotation frequency.This phenomenon imposes to

ous signal due to the change of distance from the

Fig.4.Misalignment of scanning and shaft axes.

49

P.Castellini,C.Santolini/Measurement24(1998)43–54

Fig.5.Pseudo-vibrations e?ect of misalignment of scanning and shaft axes.

has some practical consequences on the choice of

the vibrometer resolution and acquisition gain:in

other words,the misalignment e?ect hides the

vibration signal.

To eliminate the undesired signal the best solu-

tion seems to be the use of a variable?ltering of

the RF signal,before any processing,in order to

avoid the e?ects on the choice of acquisition

parameters.With this solution,gain and resolution

can be optimised for the vibration need,and the

noise of misalignment is eliminated.

Fig.7shows the time history acquired at

di?erent radial positions on the same blade rotat-

ing in water.The presence of the low frequency Fig.6.Time histories of vibrations:e?ects of misalignment at

di?erent rotational speeds.sinusoidal signal due to misalignment is clear.The

period is coincident with a period of rotation and

the amplitude is very large with respect to the surface point and the vibrometer head and,if the

vibration displacement.This amplitude changes error is large,to an in-plane velocity of the ana-

linearly with the radial position,because the dis-lysed surface.In fact,if a non-perfect alignment is

tance variation during a turn decreases with the realised,the distance between the laser interferom-

opening of the cone described by the laser beam. eter and the target point on the surface of the disk

The high frequency signal of vibration is super-changes with a sinusoidal law with a frequency

imposed on the noise signal.The amplitude varies corresponding to the rotation speed.The laser spot

with position because in these conditions the blade describes a circle on the surface itself,instead of

has a simple?exional deformation.The amplitude being steady in the disk-?xed co-ordinate system.

ratio between vibration and misalignment signal This e?ect is quite negligible,whereas the?rst one

is,sometimes,lower than0.8.

is more important:in fact,if the measurement is

possible also with this distance variation,this e?ect Fig.8shows the time history acquired at

50P.Castellini,C.Santolini /Measurement 24(1998)43–54

(a)

(b)

(c)

Fig.8.Velocity vibration signal at di ?erent rotational speeds.

(a)

(b)

(c)

the presence of gas bubbles around the propeller.Fig.7.Velocity vibration signal at di ?erent positions.

The quality of rotating point tracking seems to be good;indeed there are no visible e ?ects of speckle noise on the recovered signal.

di ?erent speeds on the same point on a blade.The correspondence between the frequency and phase The variation of rotational speed can naturally cause a change of amplitude and of spatial and of the carrier signal and the rotation speed is respected in the whole range of velocity.

frequency distribution of excitation forces.In fact,the excitation forces due to turbulence and thrust When the speed is increasing the available level of vibration signal decreases.This can be explained have a random distribution,independent of the rotational speed.Other forces,like unbal-by the high dynamic range of acquisition for the variation of the amplitude due to misalignment ancements and mechanical misalignment,are narrow band excitations,but lower in amplitude.

and vibration signals,and for the e ?ects due to

51

P.Castellini,C.Santolini/Measurement24(1998)43–54

(a)

(b)

Fig.9.Modal analysis of propeller steady in water.

The hydrodynamic phenomena such as vortex in water of a steady propeller on a grid of32×32 shedding or cavitation have periodic-random char-

points are shown.

acteristics.The study of this kind of signal needs Fig.10shows vibration maps obtained with a the acquisition of very long time histories and the

propeller rotating at9rps.In this case,the grid of development of speci?c analysis tools.acquisition points is only8×8points to reduce In Fig.9some of the results of vibration analysis

the acquisition time needed,which is higher in

52P.Castellini,C.Santolini/Measurement24(1998)43–54

(a)

(b)

Fig.10.Vibration map of propeller rotating in water at v=9rps.

rotating conditions where40synchronous averages present.In any case,the di?erent acquisition are performed to highlight the contribution of

parameters induce a di?erent representation of the natural modes.vibration?eld and some di?erences can be due The comparison shows a good correspondence

not only to the reduced spatial resolution,but also between the deformation shapes,in particular at to the acquisition parameter.In fact,the presence lower frequencies,where the coarse grid used in

of the misalignment and,overall,of noise due to rotating tests can represent the smoothed modes gas bubbles,a?ects the choice of acquisition

53

P.Castellini,C.Santolini/Measurement24(1998)43–54

parameters.The quality of signal can be improved therefore increases the mass of water interested by with the use of a number of averages,but the

the blade dynamic behaviour.The mass of water acquisition time can become unacceptable.It is‘‘around’’the blades increases,and the resonance necessary to choose a compromise between the

frequencies of the system probably decrease. quality of measurement in operative conditions On the contrary,the e?ects of frequency and time consumption(spatial resolution of the

increment due to di?erent conditions of constraint grid,frequency resolution and number of averages)and to centrifugal force present in rotating systems to obtain good results.

are not important in this case.In fact,the boss is Some di?erences are also observed in the fre-a rigid body with high mass,with respect to the quency of power spectrum peaks.In particular,

blades,and has a very low displacement in free–when the propeller is rotating the natural frequen-free conditions,with no di?erences in constraint cies are lower than the same ones measured in

conditions.Moreover,the rotational speed is very steady conditions.The variation of vibration fre-low(about0.6m/s of peripheral speed)and the quencies when a structure is working in water is

mass of the very thin blades is low,too.Therefore known as the virtual mass e?ect:in fact,the?uid the centrifugal forces on the blades and the increase around the object is induced by the structure to

of sti?ness are negligible.

vibrate and it is necessary to calculate also its mass Finally,in rotating conditions the bending is to understand the modal behaviour[9].

observed as the most important vibration mode. The tests performed with the propeller rotating In fact,the low frequency of excitation and the put in evidence an e?ect which is larger than the

high torsional sti?ness of blades determine the e?ect obtained in the steady case,with an addi-high amplitude of this kind of deformation,with

low excitation energy on high frequency modes. tional reduction of vibration frequencies,as is

shown in Fig.11.The variation of virtual mass is On the other hand,Wu and Moslehy[8]demon-probably due to the hydrodynamic action of the

strate that with multiple-point distributed excita-working propeller.The thrust transmits the vibra-tion,antisymmetric modes,e.g.torsional ones,of tion of the blades through the water?ow and

geometrically symmetric structures cannot be

Fig.11.Added virtual mass incremental(AVMI)factor with propeller steady and rotating at7and9rps.

54P.Castellini,C.Santolini/Measurement24(1998)43–54

ning laser Doppler vibrometer for modal testing,14th Int. determined.Therefore the excitation due to hydro-

Modal Analysis Conf.,Dearborn,1996,pp.816–836. dynamic e?ects,gas bubbles or cavitation hardly

[3]S.J.Rothberg,N.A.Halliwell,Vibration measurement on induces torsion on the blade structure.

rotating machinery using laser Doppler velocity,J.Vibr.

Acoust.116(1994)326–331.

[4]A.Felske,Studying source of brakes noise with coherent

optical and holographic measuring techniques,Proc.Int.

Symp.on Transportation Noise,Pretoria,1981,pp.1–14. Acknowledgements[5]J.D.Fieldhouse,T.P.Newcomb,Double pulsed holography

used to investigate noisy brakes,https://www.doczj.com/doc/d76639380.html,ser.Eng.25 The authors thank Ing.G.Zepponi,Professor

(1996)455–495.

[6]I.Bucher,P.Schmiechen,D.A.Robb,D.J.Ewins,A laser-

G.Messina and INSEAN for their support of this

based measurement system for measuring the vibration on research.

rotating discs,1st Int.Conf.on Vibration Measurements

by Laser Techniques,SPE,Ancona,1994,pp.398–408.

[7]P.Castellini, C.Santolini,Vibration measurements on

blades of naval propeller rotating in water,2nd Int.Conf.

on Vibration Measurements by Laser Techniques,Ancona, References

1996,pp.186–194.

[8]J.Wu,F.A.Moslehy,On modal testing using speaker for

[1]A.K.Reinhardt,J.R.Kadambi,R.D.Quinn,Laser

excitation,13th Int.Modal Analysis Conf.,Nashville,

vibrometry measurements of rotating blade vibrations,8th1995,pp.24–29.

Congress and Exposition on Gas Turbine Institute,IGTI,

[9]M.Amabili,G.Dal Piaz,C.Santolini,Free-edge circular

New York,1994,pp.453–461.plates vibrating in water,Modal Anal.10(3)(1995)

[2]A.B.Stanbridge,D.J.Ewins,Using a continuously-scan-

187–202.

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《餐饮船舶生活污水污染物排放标准》

《餐饮船舶生活污水污染物排放标准》 编制说明 (报批稿) 《餐饮船舶生活污水污染物排放标准》编制组 二O一O年十月

目录 前言 (1) 1、项目背景 (1) 1.1项目来源 (1) 1.2工作过程 (1) 2重庆市餐饮船舶业基本情况 (1) 2.1餐饮船舶的来历与定义 (1) 2.2重庆市餐饮船舶发展概况 (2) 2.3重庆市餐饮船舶水污染状况 (3) 2.4餐饮船舶污水治理状况 (8) 2.5餐饮船舶污染管理状况 (8) 3其他地区餐饮船舶发展与污染控制 (9) 4船舶污水治理技术分析 (9) 5国内外餐饮船舶污染物排放相关标准沿革及比较 (11) 5.1餐饮船舶污染控制的现行标准 (11) 5.2现行标准产生的背景 (11) 5.3国内外相关标准的发展状况 (12) 5.4现行标准存在的问题 (13) 6标准制定的必要性 (14) 6.1保障饮用水源水质安全 (14) 6.2更好地贯彻执行相关法律法规 (15) 6.3适应和促进船舶水污染控制技术发展 (15) 6.4建全污染物排放标准体系 (16) 7标准主要技术内容 (16) 7.1指导思想 (16) 7.2法律地位及适用范围 (16) 7.3标准的基本构架 (16) 7.4术语及定义的来源 (17) 7.5标准控制指标和限值确定 (17) 8本标准与国内外相关标准的比较 (22) 8.1本标准与其他国家、地区及国际组织相关标准比较 (22) 8.2本标准与国内相关标准比较 (23) 9标准实施的环境效益及经济技术分析 (23) 9.1环境效益分析 (23) 9.2经济效益分析 (24) 10对实施本标准的建议 (25) 重庆市环境科学研究院Ⅰ

船舶电工试题

试题一(红色字母是答案) 1、=_______A=_______μA。 A.50/5×10-5 B.5×10-5/5 C.5×10-3/50 D.5×10-5/50 2、电场力推动电荷移动而做功,衡量电场力做功能力大小的物理量是______。 A.电压B.电容C.电流D.电动势 3、不论电路如何复杂,总可归纳为由电源、_______、中间环节(控制装置、导线)三部分组成。 A.电阻 B.电容 C.电感D.负载 4、电流的实际方向与产生这一电流的电子运动方向______。 A.相同B.相反 C.超前90度 D.在直流电路中相反;在交流电路中,相同5、有一额定值为5W,500Ω的线绕电阻,其额定电流为_____,在使用时电压不得超过_____。 A.0.01A/5V B.0.1A/50V C.1A/500V D.1A/50V 6、当电压、电流的参考方向选得一致时,电阻上的电压和电流关系可用下式表示。 A.I=U/R B.I=RU C.R=IU D.I=-U/R 7、电阻串联的特征是电流_____,各电阻分配的电压与其成_____。 A.相同/反比 B.相同/正比 C.不同/反比 D.不同/正比 8、两个电阻相串联接入电路,各分得的电压与其阻值的关系是_____。 A.成正比 B.成反比 C.在直流电路中成正比,在交流电路中成反比 D.在直流电路中成反比,在交流电路中成正比 9、能定量地反映磁场中某点的磁场强弱的物理量是_____。 A.磁通密度 B.磁力线 C.磁通 D.电磁力 10、磁力线用来形象地描述磁铁周围磁场的分布情况,下列说法错误的是_____。 A.每一根磁力线都是闭合的曲线 B.任二根磁力线都不能交叉 C.磁力线的长短反映了磁场的强弱 D.任一根磁力线上的任一点的切线方向即为该点的磁场方向 11、通电导体切割磁力线将会产生感应电动势,确定磁场、导体运动和感应电动 势方向关系应用_____。 A.右手螺旋定律 B.左手定则C.右手定则 D.楞决定律

交通运输部关于印发船舶大气污染物排放控制区实施方案的通知(交海发[2018]168号)英文版

Implementation Scheme of the Domestic Emission Control Areas for Atmospheric Pollution from Vessels1 by Ministry of Transport of the People’s Republic of China on30th Nov.2018 In order to implement the national policies on ecological civilization development,pollution prevention and control,to protect the blue skies,as well as to facilitate the green shipping development and the energy saving and emission reduction of vessels,this Implementation Scheme is formulated in accordance with the Air Pollution Prevention and Control Law of the People’s Republic of China and the applicable international conventions,and on the basis of the Implementation Scheme of the Domestic Emission Control Areas for Vessels in the Pearl River Delta,the Yangtze River Delta and the Bohai-Rim Area(Beijing,Tianjin and Hebei) (JHF[2015]No.177). 1.Objectives The Domestic Emission Control Areas for Atmospheric Pollution from Vessels(hereinafter referred to as“DECAs”)are designated to control and reduce emissions of atmospheric pollutants including SOx,NOx,particulate matters(PMs)and volatile organic compounds (VOCs)from vessels and to improve the air quality of coastal areas and inland river port cities. 2.Principles The DECAs are designated according to the following principles: (i)Promoting a coordinated development of the environment quality improvement and the shipping economy growth. (ii)Strengthening the control of air pollution from vessels. (iii)Complying with the international conventions and domestic laws. (iv)Taking a phased-in approach and conducting pilot programs. 3.Scope of Application The Scheme applies to vessels navigating,berthing and operating in the DECAs. 4.Geographic Scope of the DECAs The DECAs referred to in the Scheme include both the coastal control area and the inland river control area. The coastal control area covers the sea area enclosed by the60coordinates listed in Table1, and the sea area in Hainan waters is enclosed by the20coordinates listed in Table2. The inland river control area is the navigable waters of the main stream of the Yangtze River (from Shuifu,Yunnan to the mouth of the Liuhe River,Jiangsu)and the main stream of the Xijiang River(from Nanning,Guangxi to Zhaoqing,Guangdong),the coordinates of the starting and ending points are listed in Table3. Table1Coordinates of the Boundary Control Points in the Coastal Control Area 1This English version of Implementation Sheme for DECAs is only for refrence,whileas the documents issued by MOT should be used as the officail version.

中国船舶企业排名

中国船舶企业排名 重点企业名称 1. 大连船舶重工集团有限公司 2. 江南造船(集团)有限责任公司 3. 沪东中华造船(集团)有限公司 4. 渤海船舶重工有限责任公司 5. 上海外高桥造船有限公司 6. 国营武昌造船厂 7. 广州广船国际股份有限公司 8. 中国长江航运集团金陵船厂 9. 江苏新世纪造船股份有限公司 10. 南通中远川崎船舶工程有限公司 11. 上海澄西船舶有限公司 12. 江苏扬子江船厂有限公司 13. 中国长江航运集团青山船厂 14. 天津新港船厂 15. 扬帆集团有限公司 16. 福建省马尾造船股份有限公司 17. 扬州大洋造船有限公司 18. 临海市江海造船有限公司 19. 广州黄埔造船厂 20. 国内贸易部口岸船舶工业公司

21. 浙江造船有限公司 22. 江苏东方造船有限公司 23. 青岛北海船舶重工有限责任公司 24. 淮滨县江淮船业有限公司 25. 烟台莱佛士船业有限公司 26. 乐清市七里港船厂 27. 台州市宏冠造船有限公司 28. 国营芜湖造船厂 29. 山东省黄海造船有限公司 30. 中国长江航运集团江东船厂 31. 广西桂江造船厂 32. 厦门船舶重工股份有限公司 33. 上海爱德华造船有限公司 34. 常石集团(舟山)船业发展有限公司 35. 中国人民解放军第4808厂 36. 山东省威海船厂 37. 南通惠港造船有限公司 38. 福建省东南造船厂 39. 烟台来福士海洋工程有限公司 40. 常石集团(舟山)大型船体有限公司 41. 泰州三福船舶工程有限公司 42. 天津新河船舶重工有限责任公司

43. 乳山市卧龙滩拆船厂 44. 扬州龙川船业有限公司 45. 南京永华船业有限公司 46. 杭州东风船舶制造有限公司 47. 国营西江造船厂 48. 大连新船重工船舶舾装有限公司 49. 荣成市海达造船有限公司 50. 江苏省镇江船厂有限责任公司 51. 国营川东造船厂 52. 荣成市寻山兴海造船有限责任公司 53. 江西江洲联合造船有限责任公司 54. 荣成市拆船公司 55. 宁波新乐造船有限公司 56. 中国长江航运集团宜昌船厂 57. 温岭市合兴船舶修造厂 58. 青岛灵山船业股份有限公司 59. 台州腾龙造船厂 60. 重庆东风船舶工业公司 61. 大连今冈船务工程有限公司 62. 乐清市黄华船舶修造有限公司 63. 荣成市泓运船业有限公司 64. 南京东佳船舶制造有限公司

船舶污染物排放标准

船舶污染物排放标准 UDC628.191:629.12 GB3552-83 (1983年4月9日中华人民共和国城乡环境保护部发布1983年10月1日实施) 本标准为贯彻《中华人民共和国环境保护法(试行)》,防治船舶排放的污染物对水域污染而制订。 本标准适用于中国籍船舶和进入中华人民共和国水域的外国籍船舶。 1.排放规定 1.1船舶排放的含油污水(油轮压舱水,洗舱水及船舶舱底污水)的含油量,最高容许排放浓度应符合表1规定。 表1 船舶含油污水最高容许排放浓度

1.2船舶排放的生活污水,最高容许排放浓度应符合表2规定。 表2 船舶生活污水最高容许排放浓度(毫克/升) 1.3船舶垃圾排放应符合表3规定。 表3 船舶垃圾排放规定

2.其他规定 2.1名词解释 2.1.1船舶:系指海上、内河各类船舶包括水翼船、气垫船、潜水器、固定的或浮动的工作平台。 2.1.2距最近陆地:系指按照领海基线作为起点计算的距离。 2.1.3含油污水:系指含有原油和各种石油产品的污水。 2.1.4生活污水:系指含有粪、尿及船舶医务室排出的污水。 2.1.5漂浮物质:系指漂浮的垫舱物料、衬料及包装材料等。 2.1.6其他垃圾:系指纸制品、破布、玻璃、金属、瓶子、陶瓷品及其类似废弃物。 2.2当地方执行本标准不适于当地环境特点(如集中生活水源,经济渔业区等)

时,可以按照国家有关规定制订地方污染物排放标准。 3.标准的监测 制订本标准依据的监测分析方法是:《船舶污染物监测分析方法》 附加说明: 本标准由中华人民共和国交通部提出。 本标准由交通部水运科学研究所,交通部标准计量研究所负责起草。 本标准委托交通部负责解释。

船舶电气设备及系统相关试题(doc 13页)

船舶电气设备及系统相关试题(doc 13页)

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船舶电气设备及系统(练习题) 选择题 1.电动机的输出功率的大小取决于____。(D) A.电动机的额定功率 B.负载转矩 C.电动机的转速 D.电动机的转速及负载转矩 2.直流发电机输出电压是从____两端输出的。(B) A.换向器 B.电刷 C.励磁线圈 D.都不是 3.直流发电机中感应电势与____成比例。(B) A.励磁电流 B.主磁极磁通 C.转子转速 D.转子转速与主磁极磁通的乘积 4.并励直流电动机可通过____使其反转。(B) A.该变电源电压极性 B.改变电枢绕组两端电压极性 C.同时改变励磁电流及电枢电流的方向 D.改变负载转矩的方向 5.直流电动机通常用____方法启动。(B) A.直接起动 B.电枢回路串电阻 C.励磁回路串电阻 D.空载启动 6.____式直流电动机当负载转矩增大时,转速降最大(C) A.他励 B.并励 C. 串励 D. 复励 7.直流电动机电枢绕组中的电流是____。(B) A.直流 B.交流 C.脉动

内河船舶大气污染物排放清单目录及编写要求

附录 B (规范性附录) 内河船舶大气污染物排放清单目录及编写要求 B.1 排放清单目录 B.1.1 清单编制概况 B.1.1.1.1 任务由来 B.1.1.1.2 清单编制范围及概况 B.1.1.1.3 排放总量概况 B.1.2 计算参数及来源说明 B.1.2.1.1 静态数据及来源说明 B.1.2.1.2 活动水平数据及来源说明 B.1.2.1.3 排放因子数据及来源说明 B.1.3 排放清单 B.1.3.1.1 船舶分类型大气污染物排放清单 B.1.3.1.2 船舶分运行工况大气污染物排放清单 B.1.3.1.3 船舶大气污染物排放空间分布 B.1.3.1.4 船舶大气污染物排放时间分布 B.1.4 排放清单不确定性分析 B.1.4.1.1 模型输入的定量不确定性分析 B.1.4.1.2 排放清单的定量不确定性分析 附图 (1)不同用途船舶污染物排放贡献图 (2)不同吨位船舶污染物排放贡献图 (3)不同运行工况大气污染物排放贡献图(主机、辅机、总排放) (4)船舶大气污染物排放空间分布特征图 (5)船舶大气污染物排放时间变化特征图 B.2 排放清单编写要求 B.2.1 清单编制概况应包括的主要内容 (1)概述任务由来,明确清单编制空间范围、时间范围,说明清单编制范围内的港口、航道概况; (2)概述清单编制范围内,内河船舶各大气污染物的排放总量情况。 B.2.2 计算参数及主要说明应包括的主要内容 (1)以列表和图的形式描述清单编制范围内,分时空范围、分船舶类型的船舶艘次信息,列表说明各类型内河船舶的主、辅机额定净功率分布情况,概述编制范围内的船舶燃油类型及燃油硫含量,概

船舶污水处理技术方案

船舶污水处理技术方案 随着科技水平的发展,各种污水处理技术和设备也在不断发展,处理方法多种多样,在各种船舶上均已得到了广泛的应用,根据船舶污水的种类及数量,可以将船舶污水分为油污水、黑水、厨房灰水、洗涤灰水。 1 油污水处理: 1)根据船舶产生的油污水量的多少,一般可以在动力舱设置油污水处理装置,以处理舱底含油污水。根据舱室的大小、机械设备数量、舱室分布情况,可以设单个舱室的油污水处理系统,也可以将全船油污水通过输送泵统一收集在油污水贮存舱内,再通过油污水处理装置集中处理,经处理后排放的油污水满足《73/78防治公约》的要求,排放水的含油量不大于15ppm。通过油份浓度计监测排出水的含油量,当含油量超过排放标准时,将不合格的水返回舱底继续处理知道合格。 2)按照MEPC.107(49)决议对油污水处理设备技术条件的修改,原来普遍采用的重力法分离油污水技术已不能满足处理含表面活性剂的C类试验液的要求,因此,需对油污水处理设备进行改进,在重力分离的基础上采用超滤、膜分离、化学破乳等方法以处理乳化状态下的油污水。 3)考虑到油污水对水域污染的严重性,及时经过油污水处理装

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