专业英语L2.ppt

Part Ⅰ Mine Ventilation LESSON 2 Energy Changes in Fluid Flow 流体流动的能量变化 [教学内容] Energy terms Energy changes Bernoulli energy equation LESSON 2 Energy Changes in Fluid Flow [教学目的] 要求学生熟记 head、static energy、velocity energy、potential energy incompressible fluid等专业词汇，达到英文与中文相互熟练翻译的程度 深入理解Energy terms、energy changes、Bernoulli energy equation等内容，达到熟练阅读和正确、通顺地翻译的程度 [教学重点、难点] Bernoulli energy equation [课时安排] 1 credit hour [授课方法] 讲授与讨论相结合 LESSON 2 Energy Changes in Fluid Flow 复习旧课 回忆exhaust shaft、colliery、trapper专业词汇的中文含义 Review of the various methods of mine ventilation in history LESSON 2 Energy Changes in Fluid Flow New Words and Expressions head static energy velocity[vil?s?ti] energy potential energy incompressible[,ink?mpres?bl] fluid conduit[k?ndit] LESSON 2 Energy Changes in Fluid Flow head 液压，气压：液体或气体产生的压力；压差 static energy 静压能 velocity energy 动能 potential energy 位能 incompressible fluid 不可压缩流体 conduit n.管道, 导管, 沟渠 泉水, 喷泉 Mine Ventilation is normally an example of a steady flow process, that is, one in which none of the variables of flow changes with time. Transition and loss in energy are involved in such a process, and it is important to understand their nature and to be able to express them mathematically. LESSON 2 Energy Changes in Fluid Flow Mine Ventilation is normally an example of a steady flow process, that is, one in which none of the variables of flow changes with time 正常情况下，矿山通风是一种稳定流动过程，也就是说，在这种流动过程中，所有流动变量不随时间发生变化。 Transition and loss in energy are involved in such a process, and it is important to understand their nature and to be able to express them mathematically. 能量转换和能量损失包含在这个过程中，重要的是：我们应了解能量转换和能量损失的特性，并能精确地表征出来。 Energy changes are basic to the calculation of the mine quantity and head, one of the ultimate objectives of mine-ventilation engineering. An expression relating the energy variables may be developed as follows. LESSON 2 Energy Changes in Fluid Flow Energy changes are basic to the