贯流式水轮机课件

1、CHAPTER 9Bulb TurbinesIntroduction 9.1 General arrangement9.2 Main components9.3 Condition control 9.4 Monitoring instruments 9.5 Assembly and dismantlingIntroductionThe Bulb turbine is a reaction turbine which is used for the lowest heads. It is characterized by having the essential turbine compone

2、nts as well as the generator inside a bulb, from which the name is developed. A main difference from the Kaplan turbine is moreover that the water flows with a mixed axial-radial direction into the guide vane cascade and not through a scroll casing. The guide vane spindles are inclined in relation t

3、o the turbine shaft. Contrary to other turbine types this results in a conical guide vane cascade.The Bulb turbine runner is of the same design as for the Kaplan turbine, and it may also have different numbers of blades depending on the head and water flow.Introduction贯流式电站优点：贯流式电站优点：(1)(1)电站从进水到出水方

4、向基本上是轴向贯通。电站从进水到出水方向基本上是轴向贯通。 (2)(2)贯流式水轮机具有较高的过流能力和大的比转速。贯流式水轮机具有较高的过流能力和大的比转速。(3)(3)贯流式水电站的机组结构紧凑，与同一规格的转桨式机组相贯流式水电站的机组结构紧凑，与同一规格的转桨式机组相比其尺寸较小，可布置在坝体内，取消了复杂的引水系统比其尺寸较小，可布置在坝体内，取消了复杂的引水系统(4)(4)贯流式水轮机适合作可逆式水泵水轮机运行，进出水流道没贯流式水轮机适合作可逆式水泵水轮机运行，进出水流道没有急转弯，使水泵工况和水轮机工况均能获得较好的水力性能。有急转弯，使水泵工况和水轮机工况均能获得较好的水力性

5、能。 (5)(5)贯流式水电站一般比立轴的轴流式水电站建设周期短，投资贯流式水电站一般比立轴的轴流式水电站建设周期短，投资小，收效快，淹没移民少，电站靠近城镇，有利于发挥地区兴建电小，收效快，淹没移民少，电站靠近城镇，有利于发挥地区兴建电站的积极性。站的积极性。9.1 General arrangementA general arrangement of a Bulb turbine plant is shown in Fig. General arrangementFig. 9.2 shows the turbine in more detail.9.2 Main compo

6、nentsThe Bulb turbine consists of the following main components:- stay cone (座环座环)- runner chamber (转轮室转轮室)- draft tube cone (尾水管锥形管尾水管锥形管)- generator hatch (发电机舱门发电机舱门)- rotating parts (旋转部件旋转部件)- turbine bearing (水轮机轴承水轮机轴承)- shaft seal box (主轴密封盒主轴密封盒)- guide vane mechanism (导水机构导水机构)9.2.1 Stay c

7、one座环由内环、外环、外环里衬、上部竖井和下部竖井、上下导座环由内环、外环、外环里衬、上部竖井和下部竖井、上下导流板等组成。流板等组成。 9.2.1 Stay cone整个座环被分成八个扇形块，各块之间用螺栓紧固。整个座环被分成八个扇形块，各块之间用螺栓紧固。9.2.1 Stay cone垂直面上的上支柱和下支柱较粗，并具有中空的内腔。下支柱垂直面上的上支柱和下支柱较粗，并具有中空的内腔。下支柱与支墩连接，两者的内腔相通，从而形成了灯泡体的水轮机部分经与支墩连接，两者的内腔相通，从而形成了灯泡体的水轮机部分经过该支柱的支墩内腔而通向灯泡体头部的通道。在这个支柱内还设过该支柱的支墩内腔而通向灯

8、泡体头部的通道。在这个支柱内还设有水管和油管。上支柱内腔装有水管和其他设备，该内腔还是由电有水管和油管。上支柱内腔装有水管和其他设备，该内腔还是由电站厂房进入机组灯泡体的通道。站厂房进入机组灯泡体的通道。9.2.2 Runner chamber1 1、结构：结构：转轮室由三个环带组成转轮室由三个环带组成1 1）与导水机构相毗连的锥形环带；）与导水机构相毗连的锥形环带；2 2）作为转轮室的球形环带；）作为转轮室的球形环带；3 3）与尾水管毗连的后部锥形环带。）与尾水管毗连的后部锥形环带。转轮室分瓣结合面采用法兰连接，并应有可靠的止漏措施。混转轮室分瓣结合面采用法兰连接，并应有可靠的止漏措施。混凝

9、土仅浇灌到水轮机的水平分半面处，使水轮机室上部可拆卸，凝土仅浇灌到水轮机的水平分半面处，使水轮机室上部可拆卸，以供装拆转轮之用。以供装拆转轮之用。为了观察转轮和转轮室，在后部锥形环带上开有进人孔。为了观察转轮和转轮室，在后部锥形环带上开有进人孔。在中心线附近，转轮室由不锈钢制成，以抵制气蚀侵蚀。在中心线附近，转轮室由不锈钢制成，以抵制气蚀侵蚀。9.2.2 Runner chamber2 2、转轮扫膛、转轮扫膛1 1）原因）原因流道冲水后，由于浮力的影响，转轮会上浮，而转轮室会整流道冲水后，由于浮力的影响，转轮会上浮，而转轮室会整体下沉变形，这样造成静态下调整好各部间隙和受力发生变化，体下沉变形

10、，这样造成静态下调整好各部间隙和受力发生变化，加上机组运行后，桨叶在水力作用下会带动整个转动部分轴向加上机组运行后，桨叶在水力作用下会带动整个转动部分轴向“窜动窜动”，这样，桨叶就容易与转轮室发生扫膛。，这样，桨叶就容易与转轮室发生扫膛。2 2）危害）危害轻度得扫膛会加大机组振动和机组的运行噪音，过大的扫膛轻度得扫膛会加大机组振动和机组的运行噪音，过大的扫膛会使桨叶卡阻甚至损坏。会使桨叶卡阻甚至损坏。 9.2.3 Guide vane mechanism1 1、结构、结构灯泡贯流式机组的导水机构由内、外配水环、导叶、导叶轴灯泡贯流式机组的导水机构由内、外配水环、导叶、导叶轴承、导叶操作环、重锤

11、、连杆拐臂及保护、限位装置等组成。承、导叶操作环、重锤、连杆拐臂及保护、限位装置等组成。9.2.3 Guide vane mechanism左图为外环结构，右图为导叶及导水机构内外环结构。左图为外环结构，右图为导叶及导水机构内外环结构。9.2.3 Guide vane mechanism2 2、导叶、导叶导叶下轴颈依靠套在它上面的并用销子固紧的转臂通过连杆导叶下轴颈依靠套在它上面的并用销子固紧的转臂通过连杆与控制环连接。传动导叶的传动机构安置在灯泡体的水轮机部分与控制环连接。传动导叶的传动机构安置在灯泡体的水轮机部分内。内。9.2.4 Runner1 1、转轮、转轮灯泡贯流式机组转轮与轴流转桨

12、式水轮机转轮相似，同样分为灯泡贯流式机组转轮与轴流转桨式水轮机转轮相似，同样分为两类：两类：1 1）贯流定桨式（）贯流定桨式（GDGD）2 2）贯流转桨式（）贯流转桨式（GZGZ）9.2.4 Runner特点：特点：1 1）转轮叶片数一般为奇数，没有绝对对称，这样要求安装精）转轮叶片数一般为奇数，没有绝对对称，这样要求安装精度就高，而且不容易满足转动平衡和重心落在旋转轴线上；度就高，而且不容易满足转动平衡和重心落在旋转轴线上；2 2）转轮体内充满油，转动体外充满水，而且桨叶角度可调，）转轮体内充满油，转动体外充满水，而且桨叶角度可调，所以对密封要求十分高；所以对密封要求十分高；3 3）流道充满

13、水后，转轮体和桨叶会上浮，而转轮室会下沉，）流道充满水后，转轮体和桨叶会上浮，而转轮室会下沉，这样如果安装精度或水导轴承间隙调整不当，极易造成转轮扫膛这样如果安装精度或水导轴承间隙调整不当，极易造成转轮扫膛或桨叶卡阻现象，影响机组的正常运行。或桨叶卡阻现象，影响机组的正常运行。 9.2.4 Runner2 2、转轮接力器、转轮接力器1 1）位置）位置桨叶接力器布置在转轮体内，由受油器供油。桨叶接力器布置在转轮体内，由受油器供油。2 2）作用原理）作用原理接力器作为操作架，它通过耳柄、连杆和固定在叶片枢轴上的接力器作为操作架，它通过耳柄、连杆和固定在叶片枢轴上的转臂传递作用在叶片上的驱动力矩。转

14、臂传递作用在叶片上的驱动力矩。用承受轴向力的螺栓将转轮体固定在主轴上，用压入螺钉精加用承受轴向力的螺栓将转轮体固定在主轴上，用压入螺钉精加工孔内的受剪套筒承受扭矩。工孔内的受剪套筒承受扭矩。9.3 Condition controlThe general principles for condition control are the same as for the Francis turbines. Further considerations are therefore connected only to a few specific details.9.3.1 RunnerThe run

15、ner should be inspected both from above and below. Particular attention should be given to possible cavitation erosion and scratches on the blades as well as leaks around the blade flange against the hub.9.3 Condition control9.3.2 Runner chamberThe narrow gap between runner and the runner chamber sh

16、ould be checked if foreign objects may have passed the gap and made scratches in the chamber.9.3.3 Guide vane mechanismFor guide vane mechanism with individual vane servomotors on bulb turbines it should be checked that the vanes have an identical movement.9.3 Condition control9.3.4 Shaft seal boxFo

17、r Bulb turbines at standstill it should be checked that the water does not flow out of the box along the shaft into the turbine bearing.9.3.5 Generally for Bulb turbinesSpecial attention should be paid to changes in the sound when the unit is in operation.9.4 Monitoring instrumentsThe turbine is nor

18、mally equipped with the following instrumentation: A manometer connected to the upstream end of the generator bulb A vacuum meter connected to the runner chamber downstream of the runner A contact manometer for reading of the pressure in the shaft seal box water pressure pipe, which triggers alarm o

19、r alternatively stop signal at too low pressure A contact manometer giving alarm:Pressurized water in the shaft seal box upon start of the unit9.4 Monitoring instruments A contact thermometer for reading of oil temperature in the bearing housing. The thermometer has two adjustable contacts, one for alarm at high temperature and one for disconnection for the unit on further temperature rise A remote indication thermometer with two temperature sensors for reading of temperature in lower bearing pad A level