Terms and Expressions steam turbine 汽轮机 thermal energy 热能 mechanical work 机械功 nozzle 喷嘴 kinetic energy 动能 blade 叶片 rotor 转子 shaft 轴 impulse 冲动式 reaction 反动式 stage 级 pressure drop 压降 2-row stage 双列级 multistage 多级 throttling loss 节流损失 stage efficiency 级效率 internal efficiency 内效率 Isentropic 等熵 available energy 可用能 reheat factor 重热系数 stop valve 截止阀 control valve 控制阀 exhaust hood 排汽罩 piping 管道 valve-stem 阀杆 shaft-end packing 轴端漏汽 bearing 轴承 oil-pump 油泵 Notes 1. The pressure required at less than rated flow will decrease if the nozzle area is held constant, resulting in a throttling loss through the control valves of the unit at partial flows. 如果喷嘴面积保持不变，那么在部分负荷时的压力将降低，结果导致流过机组控制阀的节流损失。 2. The internal efficiency of the turbine can be obtained by dividing the total used energy by the overall isentropic available energy from throttle pressure and temperature conditions to the exhaust pressure. 总有效利用能除以汽轮机从进汽到排汽的等熵可用能可得其内效率。 Answer the Following Questions in English 1. Explain how a steam turbine operates. 2. What is the difference between an impulse and a reaction turbine? 3. How does steam impart energy to a turbine to develop work? 4. For an electrical output with 60-Hz applications, what must the rotating speed of the turbine be? In order to prevent severe turbine blade erosion, what is the moisture limit in a turbine? Translate the Following into English 1.汽轮机是以蒸汽为工质，将蒸汽的热能转变为机械能的回转式原动机。 2.喷嘴的作用是在蒸汽流过喷嘴时，使它的一部分热能转换成蒸汽的动能，并使汽流有一定的方向。 3.为了计算级的功率和效率，首先应研究流经动叶栅时汽流速度的大小和方向的确切变化情况。 4.多级汽轮机由按压力高低顺序排列的若干级组成。常见的多级汽轮机有两种：一种是冲动式，另一种是反动式。