水利水电工程专业英语

1、 Specialized English for Graduates of 2011 Contents 1 HYDROPOWER PLANT . 1 1.1 Hydropower . 1 1.2 Advantages of Hydropower . 1 1.3 Disadvantage of a Hydroplant . 2 1.4 Multi-Purpose Uses . 2 1.4.1 Irrigation . 2 1.4.2 Flood control . 2 1.4.3 Navigation . 2 1.4.4 Recreation . 2 1.4.5 Fish Breeding .

2、3 1.5 Typical Components of a Hydroelectric Plant . 3 1.5.1 Dam or Barrage . 3 1.5.2 Water-Conduit System . 3 1.5.3 Power House . 3 1.5.4 Tail Race . 3 1.5.5 Electrical Power Transmission . 4 1.6 Classification of Hydroelectric Plants . 4 1.6.1 Base-Load and Peak-Load Plants . 4 1.6.2 Plants can als

3、o be classified as follows: . 4 1.6.3 Classification on the Basis of Available Heads . 7 2 HYDRAULIC TURBINES . 10 2.1 Introduction . 10 0 12.1.1 Sub-systems of a Water Turbine . 2.2 Classification of Water Turbines. 10 2.3 Pelton Turbine . 12 2.3.1 Injector . 12 2.3.2 Runner . 12 2.3.3 Number of No

4、zzles . 13 2.3.4 Distributor . 14 2.3.5 Casing . 15 2.3.6 Jet Brake . 16 2.3.7 Tail Water Depressor System . 16 2.4 Francis Turbine . 17 2.4.1 Main Components . 18 2.4.2 Scroll Case . 18 2.4.3 Stay Vanes Ring . 18 2.4.4 Guide Vanes Mechanism . 19 2.4.5 Runner . 19 2.4.6 Draft Tube . 21 2.4.7 Head Co

5、ver. 22 2.4.8 Bottom Ring . 22 2.4.9 Shaft . 23 2.4.10 Turbine Pit Liner . 23 2.4.11 Dewatering of Turbine . 23 2.5 Propeller and Kaplan Turbine . 23 2.5.1 Introduction . 23 2.5.2 Improvement in Efficiency . 24 2.5.3 Main Components of the Runner . 24 2.5.4 Location of Servomotor . 26 2.5.5 Scroll C

6、ase . 26 2.5.6 Automatic Air Valves . 27 2.5.7 Shaft of the Hydrounit . 27 2.5.8 Over-speed Protective Devices . 27 2.6 Deriaz Turbine . 27 2.6.1 Introduction . 27 2.6.2 Servomotor . 29 3 HVAC . 30 3.1 Background . 30 3.2 Heating . 31 3.3 Ventilation . 33 3.3.1 Mechanical or forced ventilation . 33

7、3.3.2 Natural ventilation . 34 3.3.3 Airborne Illnesses . 34 3.4 Air conditioning . 34 3.5 Energy efficiency . 36 3.5.1 Heating energy . 36 3.5.2 Geothermal Heat Pump . 37 3.5.3 Ventilation Energy recovery . 37 3.5.4 Air conditioning energy . 37 3.6 Air Filtration and Cleaning . 37 3.6.1 Clean Air D

8、elivery Rate and Filter Performance . 38 3.7 HVAC industry and standards . 38 3.7.1 International . 38 3.7.2 North America (USA) . 38 3.7.3 Europe (United Kingdom) . 39 3.7.4 Australia . 40 3.7.5 Asia (India). 40 1 HYDROPOWER PLANT 1.1 Hydropower It is the power generated by using water as the energ

9、y-supplying agent. In this case, water is allowed to flow from a higher level to a lower level through a turbine where the potential energy of water is converted into kinetic energy and the turbine, in turn, rotates a generator to produce electricity. Hydropower generation depends upon the availabil

10、ity of rainwater. Clouds are formed because of the heating of seawater by the sun. They move towards the land, where low-pressure zones are formed and as they get cooled, moisture starts precipitating. The rainwater starts moving towards lower levels because of gravity, through a system of natural d

11、rains consisting of nullahs, rivulets, rivers and so on. This water can be stored in reservoirs created on the rivers, by construction of dams and can be used to generate power. After generation, the water is let out into the river and gradually travels further and ultimately reaches the sea. Here i

12、t is heated up by the sun to start the next cycle. Therefore, hydropower is nothing but conversion of solar energy into electricity through a circuitous route. 1.2 Advantages of Hydropower Hydropower generation is non-wasting self-replenishing and non-polluting. It is a physical phenomenon and no ch

13、emical change is involved. Water come out unchanged from the turbine after imparting its energy and can be used again either for power generation or for irrigation. In fact, this is done in multi-purpose river-valley schemes like the Chambal Valley development in India and the Tennessee Valley devel

14、opment in U.S.A. In the case of the Chambal Valley development, power is generated with the help of the same water in three powerhouses, situated one after another on the river, before being released into irrigation canals. As against this, coal, oil or nuclear fuel can only be used once. The supply

15、 of water is automatic and the water utilized in one season is replenished by nature in the next season. The water reaches the powerhouse site on its own-no mining operations and transportation are involved as in the case of coal or oil. Waterpower is clean as it does not produce any pollutants, whe

16、reas in the case of thermal or nuclear power generation pollution is inevitable, as toxic by-products are emitted. The hydropower plants have very high efficiencies. The turbine efficiency is above 90 percent and the overall efficiency can be above 80 percent which is much higher than that of therma

17、l plants. The hydro-plants are long lasting and many plants are still in service even 40 years after commissioning. The percentage of outages is very low, as shutdowns for repairs and maintenance are fewer. The plants are available for instant loading and a set can start taking full load within five

18、 minutes, starting from the standstill position, whereas thermal plants may take about five to six hours. 1.3 Disadvantage of a Hydroplant The initial investments are very heavy and the specific cost is high compared to a thermal plant. The time needed for construction is quite long and it affects t

19、he economy adversely as returns start flowing in late. When a lake is formed, land submergence creates its own problem. As the availability of water varies from year to year, in low rainfall years the plant capacity is under-utilized. Anyway the advantages far outweigh the disadvantages. 1.4 Multi-P

20、urpose Uses As already started earlier, a number of additional benefits can be obtained from water stored besides generating power, such as irrigation, flood control, navigation and so on. The multi-purpose use of water gives much better returns on investment and there is marked improvement in the c

21、ost-benefit ratio. 1.4.1 Irrigation The water being discharged from a powerhouse can be fed into a canal network to provide irrigation facilities to land situated down stream. As a matter of fact, in many multi-purpose projects in India, water is stored predominantly for irrigation purposes with pow

22、er generation playing a secondary role. 1.4.2 Flood control Creation of lake on a river has the inherent possibilities of flood moderation. The flood waters may be fully or partly absorbed in the lake and only regulated quantities of water are allowed to pass downstream, protecting the lower areas f

23、rom floods. This aspect assumes great importance in the case of rivers, which go on devastating large tracts of fertile land and valuable property year after year. 1.4.3 Navigation The formation of storage reservoir increases the normal water level in a river. Many pools and shallow stretches of the

24、 river get submerged underwater and a sufficient depth of water becomes available for ship to navigate these stretches. Thus facilitates economic transport of cargo and passengers. The multi-purpose development of the river Danube in Europe is a typical example of combining navigation with power gen

25、eration. Its linking up with the river Rhine has allowed the ships to pass from the North Sea to the Black Sea. Barrages have been constructed at a number of points in the river increasing the upstream water levels and power is being generated at these places. The only additional construction needed

26、 is to provide navigational locks at the sites of the barrage for the uninterrupted movement of a ship. 1.4.4 Recreation Creation a reservoir of water considerably enhances the beauty and charm of surrounding areas and tourist resorts and picnic spots are being developed in these areas. 1.4.5 Fish B

27、reeding It can take place on a large scale and fish can be made available economically to the population living in the neighboring areas. 1.5 Typical Components of a Hydroelectric Plant The main components are (Fig.1.1): (i) The dam, (ii) The water-conduit system, (iii) The powerhouse, (iv) The tail

28、-water system, (v) The switchyard, and (vi) The transmission lines. 1.5.1 Dam or Barrage A dam or a barrage is constructed on the river course resulting in an increase in the upstream water level because of the formation of a reservoir whose storage capacity is decided by the water requirement for p

29、ower generation. 1.5.2 Water-Conduit System Water-conduit system carries water from the reservoir to the power station. It may consist of a pressure tunnel and/or pipes called penstocks which may be laid above ground or underground. One penstock may feed a number of turbines, where a number of branc

30、hes have to take off. Flow-control valves may be provided before water is admitted to the turbines. A surge tank is occasionally provided to restrict the effects of water hammer. Fig.1.1 Typical layout of a high head hydroelectric plant 1.5.3 Power House The powerhouse accommodates the turbines and

31、generators, the control equipment and in some cases the transformers. Its location can be either at the surface or underground and it may be away from, at the foot of, or in the body of, the dam. 1.5.4 Tail Race The water, after passing through the turbine, is discharged into the tailrace which, in

32、turn, carries it to a river. The tailrace can be an open channel as in the case of a surface powerhouse, or a tunnel as is turbines the all from discharge The powerhouse. underground an of case the in collected in the tail race at its beginning by means of branch channels. The tailrace may discharge

33、 into the original river itself or, in rare cases, some other river when there is an inter-basin transfer of water. 1.5.5 Electrical Power Transmission The electrical power generated by the generators is fed to the step-up transformers by means of cables as the generating voltage may be much less th

34、an the transmission voltage. The power is then supplied to the transmission network via a switchyard where the switching and protective equipment is installed. The switchyard is located within a short distance of the powerhouse. Transmission lines take off in different directions to supply power to

35、the consumers. In the case of combined hydropower and irrigation multi-purpose projects, a canal network is established downstream of dam. 1.6 Classification of Hydroelectric Plants They can be classified on the basis of the operating heads, the output or some other important features, such as the nature of duty. 1.6.1 Base-Load and Peak-Load Plants Every hydro-plant is an individual entity and no two plants are identical as regards the head, availability of power and so on. A hydro-plant works as a base-l