过程装备(双语)答辩.ppt

§9-1 Basic Power Cycle using Water Vapor- Rankine Cycle 基本蒸汽动力循环---朗肯循环 RANKINE CYCLE 1?2 Saturated or superheated steam enters the turbine at state 1, where it expands isentropically to the exit pressure at state 2. 2?3 The steam is then condensed at constant pressure and temperature to a saturated liquid, state 3.The heat removed from the steam in the condenser is typically transferred to the cooling water. 3?4 The saturated liquid then flows through the pump which increases the pressure to the boiler pressure (state 4). 4?1 the water is first heated to the saturation temperature, boiled and typically superheated to state 1. Then the whole cycle is repeated. (1)朗肯循环p-v图 (2) 朗肯循环T-s和h-s图 朗肯循环热效率的计算 朗肯循环与卡诺循环比较 3.如何提高朗肯循环的热效率 A.蒸汽初压对朗肯循环热效率的影响 B.蒸汽初温对朗肯循环热效率的影响 C.乏汽压力对朗肯循环热效率的影响 §10-2 蒸汽回热循环与再热循环 (regenerative cycle and reheat cycle) (1) 蒸汽抽汽回热循环 (2)抽汽回热循环的抽汽量计算 (2)抽汽回热循环热效率的计算 为什么抽汽回热热效率提高？ 小结: 蒸汽抽汽回热循环的特点 小型火力发电厂回热级数一般为1～3级 中大型火力发电厂一般为 4～8级。 2. 蒸汽再热循环 (reheat cycle) 蒸汽再热循环的热效率 蒸汽再热循环的实践 蒸汽再热循环的定量计算 §10-3 热电联产(供)循环 抽汽调节式热电联产(供)循环 热电联产(供)循环的经济性评价 1.The Otto Cycle (奥托循环） (1) Actual cycle (实际循环) The Otto cycle is an idealization of a set of processes used by spark ignition internal combustion engines (2-stroke or 4-stroke cycles). Otto循环 a) ingest a mixture of fuel and air, b) compress it, c) cause it to react, thus effectively adding heat through converting chemical energy into thermal energy, d) expand the combustion products, and then e) eject the combustion products and replace them with a new charge of fuel and air. ??????????????????????????????????????????????????? (2) Otto循环的简化_ We model all of these happenings by a thermodynamic cycle consisting of a set of processes all acting on a fixed mass of air contained in a piston-cylinder arrangement. The exhaust and intake processes are replaced by constant-volume cooling.）???????????????????????????????????????????