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温度巡检系统设计

毕业设计/论文开题报告课题名称基于DS18B20传感器的温度巡检系统设计院系机电与自动化学院专业班电气工程及其自动化 0904 姓名 XXXXXXX 评分指导教师 XXXXX华中科技大学武昌分校毕业设计开题报告撰写要求1.开题报告主要内容1)课题设计的目的和意义;2)课题设计的主要内容;3)设计方案;4)实施计划。

5)主要参考文献:不少于5篇,其中外文文献不少于1篇。

2.撰写开题报告时,所选课题的课题名称也不得多于25个汉字,课题设计份量要适当,设计中必须是自己的设计内容。

3. 开题报告的字数不少于2000字(艺术类专业不少于1000字),格式按《华中科技大学武昌分校本科毕业设计/论文撰写规范》的要求撰写。

4. 指导教师和责任单位必须审查签字。

5.开题报告单独装订,本附件为封面,后续表格请从网上下载并用A4纸打印后填写。

6.此开题报告适用于全校各专业,部分特殊专业需要变更的,由所在系基础上提出调整方案,报学校审批后执行。

华中科技大学武昌分校学生毕业设计开题报告(此表由学生填写,指导教师、教研室、系签署意见)水力发电站的分类根据水力的特性把水力发电站分为以下几种:1.流域蓄水式电站;2.径流式电站;3.抽水式电站;4.潮汐式电站。

流域蓄水式电站是在河流上建筑大坝,修建水库,储存足够的雨水以供全年发电。

这种电站可以进一步分为高水头电站,中水头电站和低水头电站。

a.高水头电站,水头高达250多米;b.中水头电站,水头为50~250m之间;c.低水头电站,水头在50M以下。

目前电站的发电量在几百千瓦至数千兆瓦之间不等。

单机发电量有几百千瓦的,也有70万千瓦的。

因此,很难根据发电量来对电站进行分类。

径流式电站是在河流上游无适宜的水库的情况下利用河流最小流量的电站。

有时修建拦河堰坝,把水位提高到预定的数值,只允许在很小的范围内变化。

它可以单独为电站服务,或者主要为其他目标服务,并兼顾电站。

这种方案根本上是一种低水头方案,它仅适用于枯水季流量开发的年性河流。

抽水蓄能电站在峰荷期间发电,但在非峰荷期间又把水从尾水池抽回到蓄水前池供以后使用。

抽水机是由该系统其他电站的辅助电力驱动的。

因而,这类抽水蓄能电站主要用于协助现有的火电站或别的水电站调峰。

在峰荷期间,水从水库流入水轮机而产生电能。

在非峰荷期间,利用利用其他电站的剩余电能,从尾水池抽水到前池,因而这个较小的电站为另一个较大的电站补充电能。

在这样的系统中,同样的水量被一次又一次地利用,而没有被浪费。

利用潮汐发电是近代的和现代的成就。

它是根据海水在高潮期上升,在落潮期下降的原理工作的。

海水一日涨落两次。

每次落潮周期大约是12小时25分。

潮汐电站就是利用水位涨落的效益。

换言之,就是利用高低潮之间的水位差进行发电。

为此,要修建一个水池,用隔墙将其与大海隔开,只要在隔墙的空洞里安装水轮机,就可以发电。

水轮机水轮机是把水能转为机械能的机械。

所以水轮机可以被看作是由水驱动的发电机。

储存在水库里的水通过水轮机由较高水位流到较低水位的尾水渠,把势能释放给水轮机。

水轮机的作用是旋转连接在水轮机上的电机,使其发电。

将能量转化成电的形式是必要的,因为电能可以远距离输送。

与机械能或水能相比,它的损耗比例小。

水轮机可分为两类:(1)冲击式或流速式水轮机(2)反击式或压力式水轮机1冲击式水轮机在冲击式水轮机中,水流冲击水轮机水斗之前,通过收缩的喷嘴或导叶,将可用的势能(水头)全部准换为动能,即流速水头。

轮叶在空中自由旋转,每次只有部分轮叶和水接触。

水压始终是大气压。

为了防止水花飞溅并把水从水斗导入尾水渠而加设了机壳。

因此,冲击式水轮机具有以下特性:(1)水轮机流道并未完全充满水;(2)作用在轮叶上的水处于大气压之下;(3)只从轮周几处供水(通常是一处,偶尔两处或两处以上);(4)施加于水轮机上的能量全是动能。

冲击式水轮机基本上是低速水轮机,适用水头较高,一般约150m,至今未超过1000m。

不过在瑞士,冲击式水轮机已用于1770m以上的水头。

2 反击式水轮机反击式水轮机的转轮入口处,可用的势能只有部分转换为流速水头,而剩余的大部分仍为压力水头。

水轮机入口处的压力比出口处的压力高的多,而且压力在水轮机整个流道中是变化的。

大部分动力是作用在轮叶正反面的压力差产生的,只有一小部分是由流速的动力作用产生的。

由于水处于有压状态,从引水渠流至尾水渠的全部水流都处在封闭管道系统中,任何部位均无空气进入。

概括起来,反击式水轮机有以下特性:(1)水轮机流道完全充满水;(2)作用于轮叶上的水压力高于大气压力;(3)水流沿整个轮周进入水轮机;(4)水轮机利用的能量既有压力能,也有动能。

3 变压器变压器大小不一。

有的变压器像房子一样大。

而电子变压器可能和糖块一样大。

所有的变压器至少有一个线圈;大多数变压器具有两个或两个以上的线圈。

通常使用变压器的目的是改变电压等级,但有时也用于隔离电源和负荷。

变压器的类型标准电力变压器有两只线圈。

这些线圈标记为一次绕组(一次侧)和二次绕组(二次侧)。

一次绕组连接电源,二次绕组连接负荷。

在一次和二次绕组间没有电的连接。

二次绕组通过感应获得电压。

大概只有在发电厂才能见到升压变压器。

典型的发电机出口电压为13800V。

升压至345000V用来传输。

下一站是变电所,把电压降到配电定压等级,约15000V。

大型的变电所变压器具有冷却叶片,以防止变压器过热。

有的变压器安装的位置靠近用户。

Classificasiin of HydroplantsHydroelectric plants can be classified on the basis of hydraulic characteristics as follows :1.Valley storage plants.2.Run off river plants.3.Pumped storage plants.4.Tidal plants.In the case of valley storage plants,a reserovir has to created on the river to store sufficient rainwater for power generation throughout the year by constrution of a dam .These tpyes of plants are sub-divided into high-head plants,medium-head plants and plants and low-head plants.a.High-head plants——having heads of more than 250 m.b.Medium-head plants——having heads between 50 m and 250 m.c.Low-head plants——having heads less than 50 m.The plant capacities range from few hundred kilowatts to thousands of megawatts with individual umit capcities ranging from few hundred kW to 700 thousand kW and it is rather difficult to classify the plants on capacity basis .Run-off river plants are thoese which untile the minimum flow of a river having no a ppreciable pondage on its upsream side .A weir or a barrage is sometimes constructed across a river simply to raise and maitain the water level at a pre-determined level within narrow limits of fluctuation,whether solely for building the power plant or for doing somr other things where the power plant may be incidentally erectd .Sch as a scheme is essentially a low head scheme and may be suitable only on a prenial river having sufficient dry weather flow of such a magnitude as to make development worth while.A pumped storage plant generates power during peak hours, but during the off peakhours, water is pumped back from the tail water pool to the head water poolfor future use.The pumps are run by some secondary power from some other plant or some other hysroppower plant.During peak hours, the water flows from the reservoir to the turbine and electricity is generated. During off-peak hours, the excess power is avilable from some other plant, and is ultilizd for pumping water from the tail pool to the head pool. This minor plant thudsuplements the power of another major plant.In such a scheme the same water is ultilised again and again and no woter is wasted.Tidal plants for the generation of electric power are the recent and modern advancements, and essentially work on the principle that there is a rise in seawater during high tideperiod and a fall during the low ebb period . The water rises and falls twice a day ;each fall cycle occupying about 12 hours and 25 minutes. The advantage of this rise and fall of water is taken in a tidal plant. In the word ,the tidal range,i.e. the difference between high and low tide levels is utilised to generate power. This is accomplished by constructing a basin separated form the ocean by a partition wall and installing turbines in openings through this wall.Hydraulic TurbinesTurbines are mechanical hydraulic energy into mechanical energy. So turbines could be considered generators powered by water. Stored in the stream of water through the turbines by the high water level in the reservoir to the tailrace of lower water levels, the potential energy released to the turbine.Turbine is a rotary joint on the turbine motor, its power generation. Conversion of energy into electricity is necessary, because the long-distance transmission of electric energy. Compared with the mechanical energy or water, small percentage of loss.Turbines can be classified into two categories:(1)Impact type or flow type turbine(2)Impact or pressure turbine1. Pelton turbineThe Pelton turbine, turbine flow shocks before the fight, by shrinking of nozzles or guide vanes, available potential energy (head) all for kinetic energy, thevelocity head. Vanes rotate freely in the air, only some of the vanes and watercontact at a time. Water pressure is always at atmospheric pressure. In order toprevent water splashing and import of tailrace water from the bucket and add theCabinet. Therefore, Pelton turbine has the following characteristics:(1)Hydraulic turbine runner is not completely filled with water;(2)Role on the vanes of water is under atmospheric pressure;(3)Trailing wheel week only a few water (usually one, occasionally two ormore than two);(4)Kinetic energy is the energy applied to turbine.Low-speed turbine Pelton turbine is basically applicable head higher, about 150m,Has no more than 1000m 。

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