766 QTZ40塔式起重機(jī)——臂架優(yōu)化設(shè)計(jì)（有cad圖+文獻(xiàn)翻譯）

766 QTZ40塔式起重機(jī)臂架優(yōu)化設(shè)計(jì)（有cad圖+文獻(xiàn)翻譯）,766,QTZ40塔式起重機(jī)臂架優(yōu)化設(shè)計(jì)（有cad圖+文獻(xiàn)翻譯）,qtz40,塔式起重機(jī),優(yōu)化,設(shè)計(jì),cad,文獻(xiàn),翻譯 河北建筑工程學(xué)院畢業(yè)設(shè)計(jì)（論文）任務(wù)書課題名稱QTZ40塔式起重機(jī)臂架優(yōu)化設(shè)計(jì) 系： 機(jī)械工程學(xué)院 專業(yè)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 班級(jí)： 機(jī)092 姓名： 范艷東 學(xué)號(hào)： 2009307201 起迄日期： 2013年3月25日 2013年 6月21日設(shè)計(jì)（論文）地點(diǎn): 綜405 指導(dǎo)教師： 李常勝 輔導(dǎo)教師： 發(fā)任務(wù)書日期： 2013年3月 5 日 1、畢業(yè)設(shè)計(jì)（論文）目的：畢業(yè)設(shè)計(jì)是對(duì)機(jī)械專業(yè)學(xué)生在畢業(yè)前的一次全面訓(xùn)練，目的在于鞏固和擴(kuò)大學(xué)生在校所學(xué)的基礎(chǔ)知識(shí)和專業(yè)知識(shí)，訓(xùn)練學(xué)生綜合運(yùn)用所學(xué)知識(shí)分析和解決問題的能力。是培養(yǎng)、鍛煉學(xué)生獨(dú)立工作能力和創(chuàng)新精神之最佳手段。畢業(yè)設(shè)計(jì)要求每個(gè)學(xué)生在工作過程中，要獨(dú)立思考，刻苦鉆研，有所創(chuàng)新、解決相關(guān)技術(shù)問題。通過畢業(yè)設(shè)計(jì)，使學(xué)生掌握塔式起重機(jī)的總體設(shè)計(jì)、吊臂的設(shè)計(jì)、整體穩(wěn)定性計(jì)算等內(nèi)容，為今后步入社會(huì)、走上工作崗位打下良好的基礎(chǔ)。2、畢業(yè)設(shè)計(jì)（論文）任務(wù)內(nèi)容和要求（包括原始數(shù)據(jù)、技術(shù)要求、工作要求等）：（1） 設(shè)計(jì)任務(wù)： 總體參數(shù)的選擇（QTZ40級(jí)別） 結(jié)構(gòu)形式（2） 總體設(shè)計(jì) 主要技術(shù)參數(shù)性能 設(shè)計(jì)原則 平衡重的計(jì)算 塔機(jī)的風(fēng)力計(jì)算 整機(jī)傾翻穩(wěn)定性的計(jì)算（3） 吊臂的設(shè)計(jì)和計(jì)算 吊臂的形式及尺寸（變截面）（雙吊點(diǎn)） 吊臂的強(qiáng)度、穩(wěn)定性及剛度驗(yàn)算（4） 設(shè)計(jì)要求 主要任務(wù)：學(xué)生應(yīng)在指導(dǎo)教師指導(dǎo)下獨(dú)立完成一項(xiàng)給定的設(shè)計(jì)任務(wù)，編寫符合要求的設(shè)計(jì)說明書，并正確繪制機(jī)械與電氣工程圖紙，獨(dú)立撰寫一份畢業(yè)論文，并繪制有關(guān)圖表。 知識(shí)要求：學(xué)生在畢業(yè)設(shè)計(jì)工作中，應(yīng)綜合運(yùn)用多學(xué)科的理論、知識(shí)與技能，分析與解決工程問題。通過學(xué)習(xí)、鉆研與實(shí)踐，深化理論認(rèn)識(shí)、擴(kuò)展知識(shí)領(lǐng)域、延伸專業(yè)技能。 能力培養(yǎng)要求：學(xué)生應(yīng)學(xué)會(huì)依據(jù)技術(shù)課題任務(wù)，完成資料的調(diào)研、收集、加工與整理，正確使用工具書；培養(yǎng)學(xué)生掌握有關(guān)工程設(shè)計(jì)的程序、方法與技術(shù)規(guī)范，提高工程設(shè)計(jì)計(jì)算、圖紙繪制、編寫技術(shù)文件的能力；培養(yǎng)學(xué)生掌握實(shí)驗(yàn)、測(cè)試等科學(xué)研究的基本方法；鍛煉學(xué)生分析與解決工程實(shí)際問題的能力。 綜合素質(zhì)要求：通過畢業(yè)設(shè)計(jì)，學(xué)生應(yīng)掌握正確的設(shè)計(jì)思想；培養(yǎng)學(xué)生嚴(yán)肅認(rèn)真的科學(xué)態(tài)度和嚴(yán)謹(jǐn)求實(shí)的工作作風(fēng)；在工程設(shè)計(jì)中，應(yīng)能樹立正確的生產(chǎn)觀、經(jīng)濟(jì)觀與全局觀。 設(shè)計(jì)成果要求：凡給定的設(shè)計(jì)內(nèi)容，包括說明書、計(jì)算書、圖紙等必須完整，不得有未完的部分，不應(yīng)出現(xiàn)缺頁、少圖紙現(xiàn)象。1） 對(duì)設(shè)計(jì)的全部?jī)?nèi)容，包括設(shè)計(jì)計(jì)算、機(jī)械構(gòu)造、工作原理、整機(jī)布置等，均有清晰的了解。對(duì)設(shè)計(jì)過程、計(jì)算步驟有明確的概念，能用圖紙完整的表達(dá)機(jī)械結(jié)構(gòu)與工藝要求，有比較熟練的認(rèn)識(shí)圖紙能力。對(duì)運(yùn)輸、安裝、使用等也有一定了解。2） 說明書、計(jì)算書內(nèi)容要精練，表述要清楚，取材合理，取值合適，設(shè)計(jì)計(jì)算步驟正確，數(shù)學(xué)計(jì)算準(zhǔn)確，各項(xiàng)說明要有依據(jù)，插圖、表格及字跡均應(yīng)工整、清楚、不得隨意涂改。制圖要符合機(jī)械機(jī)械制圖標(biāo)準(zhǔn)，且清潔整齊。3） 對(duì)國內(nèi)外塔式起重機(jī)情況有一般的了解，對(duì)各種塔式起重機(jī)有一定的分析、比較能力。其他各項(xiàng)應(yīng)符合本資料有關(guān)部分提出的要求。3、畢業(yè)設(shè)計(jì)（論文）成果要求（包括圖表、實(shí)物等硬件要求）： 計(jì)算說明書一份 內(nèi)容包括：設(shè)計(jì)任務(wù)要求的選型、設(shè)計(jì)計(jì)算內(nèi)容、畢業(yè)實(shí)習(xí)報(bào)告等。作到內(nèi)容完整，論證充分（包括經(jīng)濟(jì)性論證），字跡清楚，插圖和表格正規(guī)（分別進(jìn)行統(tǒng)一編號(hào)）、批準(zhǔn)，字?jǐn)?shù)要求不少于2萬字；撰寫中英文摘要；提倡學(xué)生應(yīng)用計(jì)算機(jī)進(jìn)行設(shè)計(jì)、計(jì)算與繪圖。 圖紙一套不少于四張零號(hào)圖紙量。4、主要參考文獻(xiàn)：1 哈爾濱建筑工程學(xué)院主編.工程起重機(jī).北京：中國建筑工業(yè)出版社2 董剛、李建功主編.機(jī)械設(shè)計(jì).機(jī)械工業(yè)出版社3 機(jī)械設(shè)計(jì)手冊(cè).化學(xué)工業(yè)出版社（5冊(cè)）4 GB/T94621999 塔式起重機(jī)技術(shù)條件5 GB/T137521992 塔式起重機(jī)設(shè)計(jì)規(guī)范6 GB51441994 塔式起重機(jī)安全規(guī)程 7 邢靜忠ANSYS應(yīng)用實(shí)例與分析科學(xué)出版社2006 8 劉坤ANSYS有限元方法精解國防工業(yè)出版社2005 9GB/T94621999 塔式起重機(jī)設(shè)計(jì)條件 10 GB/T137521992 塔式起重機(jī)設(shè)計(jì)規(guī)范 11 GB/T51441994 塔式起重機(jī)安全規(guī)程 12劉鴻文材料力學(xué)北京：高等教育出版社2002 13李柱，徐振高互換性與測(cè)量技術(shù)北京：高等教育出版社2002 14 張東升機(jī)械零件及建筑機(jī)械重慶：重慶大學(xué)出版社.2003 15 現(xiàn)行建筑機(jī)械規(guī)范大全北京：中國建筑工業(yè)出版社.1995 16 吳慶鳴，何小新工程機(jī)械設(shè)計(jì)武昌：武漢大學(xué)出版社.2006 17劉佩衡塔式起重機(jī)使用手冊(cè)北京：機(jī)械工業(yè)出版社.2002 18 張質(zhì)文，虞和謙等起重機(jī)設(shè)計(jì)手冊(cè)北京：中國鐵道出版社1997 19 顧迪民工程起重機(jī)北京：中國建筑工業(yè)出版社1988 20 王金諾，于蘭峰起重運(yùn)輸機(jī)金屬結(jié)構(gòu)北京：中國鐵道出版社.2002 21 張鳳山，董紅光塔式起重機(jī)構(gòu)造與維修.北京：人民郵電出版社2007 22 張青工程起重機(jī)結(jié)構(gòu)與設(shè)計(jì)化學(xué)工業(yè)出版社20085、本畢業(yè)設(shè)計(jì)（論文）課題工作進(jìn)度計(jì)劃： 起 迄 日 期 工 作 內(nèi) 容2013.3.25-2013.3.282013.3.29-2013.4.132013.4.14-2013.4.202013.4.21-2013.5.152013.5.16-2013.6.52013.6.6-2013.6.192013.6.20-2013.6.21熟悉整理資料方案選擇及總體設(shè)計(jì)繪制總圖臂架設(shè)計(jì)繪制臂架裝配及結(jié)構(gòu)圖紙繪制零件圖紙準(zhǔn)備論文及答辯教研室審查意見：教研室主任簽字： 年 月 日系審查意見： 系主任簽字： 年 月 日河北建筑工程學(xué)院畢業(yè)實(shí)習(xí)報(bào)告系 別 機(jī)械工程學(xué)院 專 業(yè) 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 班 級(jí) 機(jī)092 姓 名 范艷東 學(xué) 號(hào) 2009307201 指導(dǎo)教師 李常勝 實(shí)習(xí)成績(jī) 實(shí)習(xí)報(bào)告轉(zhuǎn)眼間四年的大學(xué)生活就快結(jié)束了，然而大多數(shù)學(xué)生對(duì)于本專業(yè)的認(rèn)識(shí)還是不夠，為了使我們更多地了解機(jī)械產(chǎn)品及設(shè)備，提高對(duì)機(jī)械設(shè)計(jì)制造及其自動(dòng)化的認(rèn)識(shí)，加深機(jī)械在工業(yè)各領(lǐng)域應(yīng)用的感性認(rèn)識(shí)，開闊視野，老師安排了我們到長(zhǎng)春會(huì)展中心實(shí)習(xí)。長(zhǎng)春國際會(huì)展中心是由市政府和長(zhǎng)春經(jīng)濟(jì)技術(shù)開發(fā)區(qū)共同投資興建的大型現(xiàn)代化展覽場(chǎng)所，是集展覽、住宿、餐飲、會(huì)議、娛樂、體育、旅游、商貿(mào)、科技、信息等為一體的多功能活動(dòng)中心。一、實(shí)習(xí)目的畢業(yè)實(shí)習(xí)是學(xué)生完成了教學(xué)計(jì)劃所規(guī)定的全部理論課程的基礎(chǔ)上進(jìn)行的總結(jié)性實(shí)習(xí)，是培養(yǎng)和檢驗(yàn)學(xué)生綜合運(yùn)用所學(xué)專業(yè)的基本理論、基本技能，理論聯(lián)系實(shí)際，獨(dú)立的分析問題、解決問題的重要環(huán)節(jié)。實(shí)習(xí)在于培養(yǎng)實(shí)踐動(dòng)手能力，使所學(xué)的專業(yè)理論知識(shí)與實(shí)踐相結(jié)合，為更好地適應(yīng)社會(huì)的需求打下良好的基礎(chǔ)。通過到長(zhǎng)春國際會(huì)展中心的實(shí)習(xí)，讓我們對(duì)各種工程機(jī)械，如裝載機(jī)、挖掘機(jī)、起重機(jī)等，以及各種數(shù)控機(jī)床、精密儀器等有了更進(jìn)一步的認(rèn)識(shí)和了解。通過參觀，綜合自己所學(xué)知識(shí)，以及查閱資料，這次實(shí)習(xí)我學(xué)到了不少東西。二、實(shí)習(xí)內(nèi)容本次畢業(yè)實(shí)習(xí)，我們跟隨畢業(yè)設(shè)計(jì)導(dǎo)師李常勝老師，來到長(zhǎng)春國際會(huì)展中心，為期一天。擺在國際會(huì)展中心門口的有裝載機(jī)，挖掘機(jī)，汽車吊車等等，而塔式起重機(jī)是我著重了解的對(duì)象。（1）裝載機(jī)裝載機(jī)是一種廣泛用于公路、鐵路、建筑、水電、港口、礦山等建設(shè)工程的土石方施工機(jī)械，它主要用于鏟裝土壤、砂石、石灰、煤炭等散狀物料，也可對(duì)礦石、硬土等作輕度鏟挖作業(yè)。換裝不同的輔助工作裝置還可進(jìn)行推土、起重和其他物料如木材的裝卸作業(yè)。因此它成為工程建設(shè)中土石方施工的主要機(jī)種之一。（2）挖掘機(jī)挖掘機(jī)是用鏟斗挖掘高于或低于承機(jī)面的物料，并裝入運(yùn)輸車輛或卸至堆料場(chǎng)的土方機(jī)械。其挖掘的物料主要是土壤、煤、泥沙以及經(jīng)過預(yù)松后的土壤和巖石。從近幾年工程機(jī)械的發(fā)展來看，挖掘機(jī)的發(fā)展相對(duì)較快，挖掘機(jī)已經(jīng)成為工程建設(shè)中最主要的工程機(jī)械之一。 （3）塔式起重機(jī)塔式起重機(jī)又稱塔機(jī)，具有適用范圍廣，回轉(zhuǎn)半徑大，操作方便，工作效率高及安裝拆卸比較簡(jiǎn)便等特點(diǎn)，從而廣泛使用在建筑安裝工程中，并成為重要的施工機(jī)械之一。塔機(jī)組成一般來說塔機(jī)按各部分功能可分為：基礎(chǔ)、塔身、頂升、回轉(zhuǎn)、起升、平衡臂、起重臂、起重小車、塔 頂、司機(jī)室、變幅等部分。塔機(jī)安裝在地面上需要基礎(chǔ)部分；塔身是塔機(jī)身子，也是升高的部分；頂升部分是使得塔機(jī)可以升高；回轉(zhuǎn)是保持塔機(jī)上半身可以水平旋轉(zhuǎn)的；起升機(jī)構(gòu)用來將重物提升起來的；平衡臂架是保持力矩平衡的；起重臂架一般就是提升重物的受力部分；小車用來安裝滑輪組和鋼繩以及吊鉤的，也是直接受力部分；塔頂當(dāng)然是用來保持臂架受力平衡的；司機(jī)室是操作的地方；變幅是使得小車沿軌道運(yùn)行的。塔機(jī)工作機(jī)構(gòu)分為5種：起升機(jī)構(gòu)；變幅機(jī)構(gòu)；小車牽引機(jī)構(gòu)；回轉(zhuǎn)機(jī)構(gòu)和大車走行機(jī)構(gòu)。在此，就讓我們簡(jiǎn)單的看一下：動(dòng)臂式塔機(jī)設(shè)臂架變幅機(jī)構(gòu)，兼有架設(shè)及變幅兩種功能。小車變幅水平臂架塔機(jī)設(shè)小車牽引機(jī)構(gòu)，或稱小車變幅機(jī)構(gòu)。固定式塔機(jī)不設(shè)大車走行機(jī)構(gòu)。起升機(jī)構(gòu)、變幅機(jī)構(gòu)及小車牽引機(jī)構(gòu)在構(gòu)造上極為近似，均由電動(dòng)機(jī)、聯(lián)軸器、制動(dòng)器、減速器和卷筒等部件組成。其具體介紹如下：起升機(jī)構(gòu)：起升機(jī)構(gòu)是起重機(jī)機(jī)械的主要機(jī)構(gòu)，用以實(shí)現(xiàn)重物的升降運(yùn)動(dòng)。起升機(jī)構(gòu)通常由原動(dòng)機(jī)、減速器、卷筒、制動(dòng)器、鋼絲繩、滑輪組和吊鉤組成。回轉(zhuǎn)機(jī)構(gòu):塔機(jī)是靠起重臂回轉(zhuǎn)來保障其工作覆蓋面的?；剞D(zhuǎn)運(yùn)動(dòng)的產(chǎn)生是通過上、下回轉(zhuǎn)支座分別裝在回轉(zhuǎn)支承的內(nèi)外圈上并由回轉(zhuǎn)機(jī)構(gòu)驅(qū)動(dòng)小齒輪。小齒輪與回轉(zhuǎn)支承的大齒圈嚙合，帶動(dòng)回轉(zhuǎn)上支座相對(duì)于下支座運(yùn)動(dòng)。我們?cè)O(shè)計(jì)的QTZ500塔式起重機(jī)的回轉(zhuǎn)機(jī)構(gòu)設(shè)成單回轉(zhuǎn)式，通常由回轉(zhuǎn)電動(dòng)機(jī)、液力耦合器、回轉(zhuǎn)制動(dòng)器、回轉(zhuǎn)減速器和小齒輪組成。變幅機(jī)構(gòu):變幅機(jī)構(gòu)是實(shí)現(xiàn)改變幅度的工作機(jī)構(gòu)，用來擴(kuò)大起重機(jī)的工作范圍，提高起重機(jī)的生產(chǎn)率。變幅機(jī)構(gòu)由電動(dòng)機(jī)、減速器、卷筒和制動(dòng)器組成。功率和外形尺寸較小。變幅機(jī)構(gòu)按其構(gòu)造和不同的變幅方式分為運(yùn)行小車式和吊臂俯仰式。塔機(jī)都設(shè)有安全保護(hù)裝置，包括：起升高度限制器、起重量限制器、力矩限制器。為了提高塔機(jī)生產(chǎn)率，加快吊裝施工進(jìn)度，無論是起升機(jī)構(gòu)、變幅機(jī)構(gòu)、小車牽引機(jī)構(gòu)、回轉(zhuǎn)機(jī)構(gòu)和大車走行機(jī)構(gòu)均應(yīng)具備較高的工作速度，并要求從靜停到全速運(yùn)行，或從全速運(yùn)行轉(zhuǎn)入靜停的全過程(即啟動(dòng)和制動(dòng)過程)，都能平緩進(jìn)行，避免產(chǎn)生急劇沖動(dòng)，對(duì)金屬結(jié)構(gòu)產(chǎn)生破壞性影響。對(duì)于高層建筑施工用的自升塔機(jī)來說，由于起升高度大，起重臂長(zhǎng)，起重量大，對(duì)工作機(jī)構(gòu)調(diào)速系統(tǒng)有更高的要求。由于我的畢業(yè)設(shè)計(jì)是塔機(jī)的吊臂，通過查閱資料，我了解到：吊臂是塔機(jī)的關(guān)鍵零件之一，她是由數(shù)節(jié)臂架通過臂架接頭用銷軸連接在一起的結(jié)構(gòu)式焊接件，其制造質(zhì)量直接影響塔式起重機(jī)的使用安全和壽命，特別是吊臂下弦桿，它既是受力桿件又是小車的軌道。為使小車運(yùn)行平穩(wěn)，兩下弦桿必須滿足直線度、平面度、平行度和垂直度等技術(shù)要求。因此，吊臂下弦桿接頭的制造質(zhì)量直接影響整個(gè)吊臂的制造質(zhì)量。三、實(shí)習(xí)結(jié)果“紙上得來終覺淺，絕知此事要躬行”，通過這次實(shí)習(xí)，我學(xué)到了很多知識(shí)：（1） 了解了裝載機(jī)和挖掘機(jī)的用途；（2） 了解了塔式起重機(jī)的特點(diǎn)和結(jié)構(gòu)，并對(duì)其工作機(jī)構(gòu)和臂架做了詳細(xì)了解，對(duì)我的畢業(yè)設(shè)計(jì)起到了很重要的作用。四、實(shí)習(xí)總結(jié)在這短暫的實(shí)習(xí)過程中，我采用了看、問、查閱資料等方式，對(duì)工程機(jī)械有了更進(jìn)一步的認(rèn)識(shí)和了解，我深深的感覺到了自己所學(xué)知識(shí)的膚淺和在實(shí)際運(yùn)用中專業(yè)知識(shí)的匱乏，這使我真正領(lǐng)悟到什么叫“學(xué)無止境”。實(shí)習(xí)結(jié)束并不代表什么，它讓我發(fā)現(xiàn)了更多的不足，所以在今后的學(xué)習(xí)和工作中，我會(huì)更加用心，去充實(shí)自己，完善自己，以求知者的身份警戒自己，爭(zhēng)取在今后的工作中做一名合格的員工。 河北建筑工程學(xué)院 畢業(yè)設(shè)計(jì)（論文）開題報(bào)告課題名稱QTZ40塔式起重機(jī)臂架優(yōu)化設(shè)計(jì)系 別： 機(jī)械工程學(xué)院 專 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 班 級(jí)： 機(jī)092 學(xué)生姓名： 范艷東 學(xué) 號(hào)： 2009307201 指導(dǎo)教師： 李常勝 導(dǎo)師課題課題類別工程設(shè)計(jì)（一）塔式起重機(jī)的研究現(xiàn)狀及發(fā)展趨勢(shì) 塔式起重機(jī)是現(xiàn)代工業(yè)與民用建筑的重要施工機(jī)械之一。在高層建筑施工中，它的幅度利用度比其他類型起重機(jī)高。塔機(jī)由于能靠近建筑物，其幅度利用率可達(dá)整體幅度的80。塔式起重機(jī)的變幅及回轉(zhuǎn)機(jī)構(gòu)是可以同時(shí)實(shí)現(xiàn)重物在垂直方向和水平方向移動(dòng)的機(jī)構(gòu)，所以可以擴(kuò)大起重機(jī)的工作范圍，提高生產(chǎn)率。應(yīng)用塔機(jī)對(duì)于加快施工速度、縮短工期、降低工程造價(jià)能夠起到重要作用。塔式起重機(jī)已經(jīng)成為建筑工程業(yè)必要的技術(shù)裝備，成為衡量建筑工程業(yè)生產(chǎn)力水平高下的重要標(biāo)志之一，成為加快工程建設(shè)、確保工程整體質(zhì)量、降低工程造價(jià)、提高社會(huì)效益與經(jīng)濟(jì)效益的重要手段。塔機(jī)是在第二次世界大戰(zhàn)后才真正獲得發(fā)展的。戰(zhàn)后各國面臨著重建家園的艱巨任務(wù)，浩大的建筑工程量迫切需要大量性能良好的塔式起重機(jī)。自塔式起重機(jī)在建筑施工中顯露身手并逐漸成為工程機(jī)械一個(gè)重要分支以來，已經(jīng)有50余年歷史，其間利經(jīng)了曲折復(fù)雜的發(fā)展階段。70年代末，由于種種原因，國外塔式起重機(jī)制造業(yè)陷入了低谷，不少中小工廠紛紛停業(yè)或轉(zhuǎn)產(chǎn)，僅少數(shù)大廠得以維持。直至80年代末才呈現(xiàn)逐漸復(fù)蘇態(tài)勢(shì)，1994年為復(fù)蘇年頭，復(fù)蘇勢(shì)頭最好的國家為德國。據(jù)有關(guān)資料介紹，在塔機(jī)制造業(yè)鼎盛的70年代，西德?lián)碛懈魇剿C(jī)48500臺(tái)，80年代總量減至1/3，而近幾年，東西德合并，基建規(guī)模擴(kuò)大，塔機(jī)產(chǎn)量上升，現(xiàn)有塔機(jī)近40000臺(tái)，其中半數(shù)機(jī)齡不足5年。我國的塔機(jī)行業(yè)于20世紀(jì)50年代開始起步,相對(duì)于中西歐國家由于建筑業(yè)疲軟造成的塔機(jī)業(yè)的不景氣, 我國的塔機(jī)業(yè)正處于一個(gè)迅速的發(fā)展時(shí)期。到20世紀(jì)90年代以后，塔式起重機(jī)行業(yè)隨著行業(yè)建筑任務(wù)的增加而進(jìn)入了新興時(shí)期，年產(chǎn)量連年猛增，而且也有部分產(chǎn)品出口到了國外。全國塔式起重機(jī)的擁有總量也從20世紀(jì)50年代的幾十臺(tái)到2000年的60000臺(tái)左右。至此，無論從生產(chǎn)規(guī)模、應(yīng)用范圍、塔式起重機(jī)總量等各個(gè)角度來衡量，我國都可以稱為塔式起重機(jī)大國。從塔機(jī)的技術(shù)發(fā)展方面來看，雖然新的產(chǎn)品層出不窮，新產(chǎn)品在生產(chǎn)效能、操作簡(jiǎn)便、保養(yǎng)容易和運(yùn)行可靠方面均有提高，但是塔機(jī)的技術(shù)并無根本性的改變。塔機(jī)的研究正向著組合式發(fā)展。所謂的組合式，就是以塔身結(jié)構(gòu)為核心，按結(jié)構(gòu)和功能特點(diǎn)，將塔身分解成若干部分，并依據(jù)系列化和通用化要求，遵循模數(shù)制原理再將各部分劃分成若干模塊。根據(jù)參數(shù)要求，選用適當(dāng)模塊分別組成具有不同技術(shù)性能特征的塔機(jī)，以滿足施工的具體需求。推行組合式的塔機(jī)有助于加快塔機(jī)產(chǎn)品開發(fā)進(jìn)度，節(jié)省產(chǎn)品開發(fā)費(fèi)用，并能更好的為客戶服務(wù)。當(dāng)前塔機(jī)的發(fā)展具有如下一些特點(diǎn)和趨勢(shì)：1、吊臂長(zhǎng)度加長(zhǎng) 在六十年代初，吊臂長(zhǎng)度超過40m的較少，七十年代吊臂長(zhǎng)度已能做到70m，快速拆裝下回轉(zhuǎn)塔式起重機(jī)的吊臂長(zhǎng)度可達(dá)35m。自升式塔式起重機(jī)吊臂是可以接長(zhǎng)的，標(biāo)準(zhǔn)臂長(zhǎng)一般為3045m，可以接長(zhǎng)到5060m。重型塔式起重機(jī)吊臂則更長(zhǎng)。吊臂加長(zhǎng)可帶來更好的技術(shù)經(jīng)濟(jì)效果。隨著塔式起重機(jī)設(shè)計(jì)水平的提高，能解決由臂長(zhǎng)加大帶來的一些技術(shù)問題(如安裝和運(yùn)輸問題)。低合金高強(qiáng)度鋼材及鋁合金的廣泛采用亦為加長(zhǎng)吊臂提供了非常有利的條件。2、工作速度提高，且能調(diào)速 由于調(diào)速技術(shù)的進(jìn)步，滑輪組倍率可變，雙速、三速電動(dòng)機(jī)及直流電動(dòng)機(jī)調(diào)速的應(yīng)用，使塔式起重機(jī)工作速度在逐漸提高。起升機(jī)構(gòu)普遍做到至少具有3種工作速度，重物起升速度超過100mmin者也很多。構(gòu)件安裝就位速度可在0-10mmin范圍內(nèi)進(jìn)行選擇?；剞D(zhuǎn)速度一般可在0-1rmin之間進(jìn)行調(diào)節(jié)。小車牽引和塔式起重機(jī)行走大多也有2-3種工作速度，小車牽引速度最快可達(dá)60mmin。3、改善操縱條件 隨著塔式起重機(jī)向大型、大高度方向發(fā)展，操縱人員的能見度愈來愈差。因此需要在吊臂端部(動(dòng)臂變幅)或小車上(小車變幅)安裝電視攝象機(jī)，在操作室利用電視進(jìn)行操作。有的還采用了雙頻道的無線電遙控系統(tǒng)，不但可由地面的操作人員控制吊裝；還可根據(jù)事先編排的程序自動(dòng)進(jìn)行吊裝。4、更多地采用組裝式結(jié)構(gòu) 為了便于產(chǎn)品的更新?lián)Q代，簡(jiǎn)化設(shè)計(jì)制造、使用與管理，提高塔式起重機(jī)使用的經(jīng)濟(jì)效益，國外塔式起重機(jī)專業(yè)廠已做到產(chǎn)品系列化，部件模數(shù)化。以不同模數(shù)塔身，臂架標(biāo)準(zhǔn)節(jié)組合成變截面塔身和臂架，不僅能提高塔身、臂架的力學(xué)性能，減輕塔式起重機(jī)自重，而且可明顯減少使用單位塔架，臂架的儲(chǔ)備量，為降低成本，簡(jiǎn)化管理創(chuàng)造了條件。（二）ANSYS介紹 有限單元法是隨著電子計(jì)算機(jī)的發(fā)展而迅速發(fā)展起來的一種現(xiàn)代計(jì)算方法。它是50年代首先在連續(xù)體力學(xué)領(lǐng)域-飛機(jī)結(jié)構(gòu)靜、動(dòng)態(tài)特性分析中應(yīng)用的一種有效的數(shù)值分析方法，隨后很快廣泛的應(yīng)用于求解熱傳導(dǎo)、電磁場(chǎng)、流體力學(xué)等連續(xù)性問題。有限元思想的核心就是把實(shí)際結(jié)構(gòu)離散化，假想地使實(shí)際的結(jié)構(gòu)離散為有限數(shù)目個(gè)類似結(jié)構(gòu)的個(gè)體，然后通過分析這些有限個(gè)體的性能來求出滿足實(shí)際工程要求的計(jì)算結(jié)果，從而代替對(duì)于具體復(fù)雜實(shí)際結(jié)構(gòu)的求解。經(jīng)過離散化，應(yīng)用有限元思想，可以解決很多實(shí)際復(fù)雜的工程問題，并在理論研究和工程應(yīng)用兩方面都具有極其重要的實(shí)用價(jià)值。 ANSYS作為一個(gè)大型通用軟件，廣泛應(yīng)用于結(jié)構(gòu)、流體、聲場(chǎng)、熱、耦合場(chǎng)、電磁場(chǎng)上面，利用ANSYS軟件，能夠?qū)?shí)際模型置于各種各樣不同的復(fù)雜實(shí)際工況之中，準(zhǔn)確并合理的分析，優(yōu)化設(shè)計(jì)，減少實(shí)際試驗(yàn)的物質(zhì)和人力投入，提高工作效率，縮短研發(fā)周期從而能夠?yàn)樘岣呃麧?rùn)做出貢獻(xiàn)。使用ANSYS軟件分析，包含以下幾個(gè)過程：建立模型、劃分網(wǎng)格、加載和求解、結(jié)果后處理。若在實(shí)際應(yīng)用過程中想對(duì)其中的某一個(gè)步驟進(jìn)行改動(dòng)和變化，則依然需要重新完成其中的每一個(gè)步驟，無形中浪費(fèi)了太多的工作時(shí)間。針對(duì)現(xiàn)實(shí)情況，ANSYS提供了APDL參數(shù)化設(shè)計(jì)語言來處理類似問題，通過APDL語言及UIDL語言或類似VB、VC編程語言開發(fā)應(yīng)用界面，即可完成在ANSYS中的二次開發(fā)。二、本課題的目的（重點(diǎn)及擬解決的關(guān)鍵問題） 畢業(yè)設(shè)計(jì)是對(duì)機(jī)械專業(yè)學(xué)生在畢業(yè)前的一次全面訓(xùn)練，目的在于鞏固和擴(kuò)大學(xué)生在校所學(xué)的基礎(chǔ)知識(shí)和專業(yè)知識(shí)，訓(xùn)練學(xué)生綜合運(yùn)用所學(xué)知識(shí)分析和解決問題的能力。是培養(yǎng)、鍛煉學(xué)生獨(dú)立工作能力和創(chuàng)新精神之最佳手段。畢業(yè)設(shè)計(jì)要求每個(gè)學(xué)生在工作過程中，要獨(dú)立思考，刻苦鉆研，有所創(chuàng)新、解決相關(guān)技術(shù)問題。通過畢業(yè)設(shè)計(jì)，使學(xué)生掌握塔式起重機(jī)的總體設(shè)計(jì)、吊臂的設(shè)計(jì)、整體穩(wěn)定性計(jì)算等內(nèi)容，為今后步入社會(huì)、走向工作崗位打下良好的基礎(chǔ)。 塔機(jī)臂架作為塔機(jī)的工作裝置,在塔機(jī)產(chǎn)品的設(shè)計(jì)內(nèi)容中處于核心地位, 采用有限元分析的方法進(jìn)行塔機(jī)臂架的設(shè)計(jì)計(jì)算將會(huì)極大地提高設(shè)計(jì)效率、保證其設(shè)計(jì)質(zhì)量。我們只需借助通用有限元軟件建立模型并進(jìn)行仿真分析,就能真實(shí)地反映機(jī)械產(chǎn)品的尺寸外形特征和工作過程,并進(jìn)行各種類型的力學(xué)分析,盡早發(fā)現(xiàn)設(shè)計(jì)缺陷,從而有效地縮短研發(fā)周期,降低生產(chǎn)成本,使產(chǎn)品的結(jié)構(gòu)和性能更加合理。三、主要內(nèi)容、研究方法、研究思路1、主要內(nèi)容（1） 設(shè)計(jì)任務(wù)： 總體參數(shù)的選擇（QTZ40級(jí)別） 結(jié)構(gòu)形式（2） 總體設(shè)計(jì) 主要技術(shù)參數(shù)性能 設(shè)計(jì)原則 平衡重的計(jì)算 塔機(jī)的風(fēng)力計(jì)算 整機(jī)傾翻穩(wěn)定性的計(jì)算（3） 吊臂的設(shè)計(jì)和計(jì)算 吊臂的形式及尺寸（變截面）（雙吊點(diǎn)） 吊臂的強(qiáng)度、穩(wěn)定性及剛度驗(yàn)算（4） 設(shè)計(jì)要求 主要任務(wù)：學(xué)生應(yīng)在指導(dǎo)教師指導(dǎo)下獨(dú)立完成一項(xiàng)給定的設(shè)計(jì)任務(wù)，編寫符合要求的設(shè)計(jì)說明書，并正確繪制機(jī)械與電氣工程圖紙，獨(dú)立撰寫一份畢業(yè)論文，并繪制有關(guān)圖表。 知識(shí)要求：學(xué)生在畢業(yè)設(shè)計(jì)工作中，應(yīng)綜合運(yùn)用多學(xué)科的理論、知識(shí)與技能，分析與解決工程問題。通過學(xué)習(xí)、鉆研與實(shí)踐，深化理論認(rèn)識(shí)、擴(kuò)展知識(shí)領(lǐng)域、延伸專業(yè)技能。 能力培養(yǎng)要求：學(xué)生應(yīng)學(xué)會(huì)依據(jù)技術(shù)課題任務(wù)，完成資料的調(diào)研、收集、加工與整理，正確使用工具書；培養(yǎng)學(xué)生掌握有關(guān)工程設(shè)計(jì)的程序、方法與技術(shù)規(guī)范，提高工程設(shè)計(jì)計(jì)算、圖紙繪制、編寫技術(shù)文件的能力；培養(yǎng)學(xué)生掌握實(shí)驗(yàn)、測(cè)試等科學(xué)研究的基本方法；鍛煉學(xué)生分析與解決工程實(shí)際問題的能力。 綜合素質(zhì)要求：通過畢業(yè)設(shè)計(jì)，學(xué)生應(yīng)掌握正確的設(shè)計(jì)思想；培養(yǎng)學(xué)生嚴(yán)肅認(rèn)真的科學(xué)態(tài)度和嚴(yán)謹(jǐn)求實(shí)的工作作風(fēng)；在工程設(shè)計(jì)中，應(yīng)能樹立正確的生產(chǎn)觀、經(jīng)濟(jì)觀與全局觀。 設(shè)計(jì)成果要求：凡給定的設(shè)計(jì)內(nèi)容，包括說明書、計(jì)算書、圖紙等必須完整，不得有未完的部分，不應(yīng)出現(xiàn)缺頁、少圖紙現(xiàn)象。1） 對(duì)設(shè)計(jì)的全部?jī)?nèi)容，包括設(shè)計(jì)計(jì)算、機(jī)械構(gòu)造、工作原理、整機(jī)布置等，均有清晰的了解。對(duì)設(shè)計(jì)過程、計(jì)算步驟有明確的概念，能用圖紙完整的表達(dá)機(jī)械結(jié)構(gòu)與工藝要求，有比較熟練的認(rèn)識(shí)圖紙能力。對(duì)運(yùn)輸、安裝、使用等也有一定了解。2） 說明書、計(jì)算書內(nèi)容要精練，表述要清楚，取材合理，取值合適，設(shè)計(jì)計(jì)算步驟正確，數(shù)學(xué)計(jì)算準(zhǔn)確，各項(xiàng)說明要有依據(jù)，插圖、表格及字跡均應(yīng)工整、清楚、不得隨意涂改。制圖要符合機(jī)械機(jī)械制圖標(biāo)準(zhǔn)，且清潔整齊。3） 對(duì)國內(nèi)外塔式起重機(jī)情況有一般的了解，對(duì)各種塔式起重機(jī)有一定的分析、比較能力。2、 研究方法 （1）資料的準(zhǔn)備 通過上網(wǎng)和畢業(yè)實(shí)習(xí)，搜集同類已研發(fā)產(chǎn)品相關(guān)資料，了解國內(nèi)外塔式起重機(jī)總體設(shè)計(jì)和起升系統(tǒng)的設(shè)計(jì)的已研發(fā)的產(chǎn)品，借鑒這些產(chǎn)品的設(shè)計(jì)思路為自己的設(shè)計(jì)做準(zhǔn)備。了解所做設(shè)計(jì)中的標(biāo)準(zhǔn)部件的相關(guān)信息，為以后設(shè)計(jì)做好準(zhǔn)備。 （2）參數(shù)確定 根據(jù)所查資料，了解到起重機(jī)的相關(guān)參數(shù)，和對(duì)標(biāo)準(zhǔn)部件的了解，選擇能免租條件的相關(guān)零件。根據(jù)傳統(tǒng)設(shè)計(jì)方法并結(jié)合相似的產(chǎn)品結(jié)構(gòu)進(jìn)行具體的設(shè)計(jì)，在設(shè)計(jì)中確定個(gè)關(guān)節(jié)的合理尺寸和形狀。整體和各個(gè)部件的形狀和尺寸確定后，用二維作圖工具（autoCAD等）繪制出各主要部件的圖形圖和總裝圖。明確產(chǎn)品的具體設(shè)計(jì)尺寸和形狀。3、 研究思路 伴隨著計(jì)算機(jī)技術(shù)的進(jìn)步,目前國內(nèi)外先進(jìn)的機(jī)械產(chǎn)品設(shè)計(jì)制造都離不開有限元分析(Finite ElementAnalysis, FEA)計(jì)算,在工程設(shè)計(jì)和分析中受到越來越廣泛的重視,其計(jì)算結(jié)果不僅詳盡,更具可靠性。采用有限元分析的方法進(jìn)行機(jī)械產(chǎn)品的設(shè)計(jì)計(jì)算將會(huì)極大提高設(shè)計(jì)效率、保證其設(shè)計(jì)質(zhì)量。設(shè)計(jì)者只需借助通用有限元軟件建立模型并進(jìn)行仿真分析,就能真實(shí)地反映機(jī)械產(chǎn)品的尺寸外形特征和工作過程,并進(jìn)行各種類型的力學(xué)分析,盡早發(fā)現(xiàn)設(shè)計(jì)缺陷,從而有效地縮短研發(fā)周期,降低生產(chǎn)成本,使產(chǎn)品的結(jié)構(gòu)和性能更加合理。本文應(yīng)用有限元軟件對(duì)塔機(jī)總體及臂架結(jié)構(gòu)進(jìn)行快速校核分析。四、總體安排和進(jìn)度（包括階段性工作內(nèi)容及完成日期）2013.3.25-2013.3.28 熟悉整理資料2013.3.29-2013.4.13 方案選擇及總體設(shè)計(jì)2013.4.14-2013.4.20 繪制總圖2013.4.21-2013.5.15 臂架設(shè)計(jì)2013.5.16-2013.6.5 繪制塔身裝配及結(jié)構(gòu)圖紙2013.6.6-2013.6.19 繪制零件圖紙2013.6.20-2013.6.21 準(zhǔn)備論文及答辯五、主要參考文獻(xiàn)1 哈爾濱建筑工程學(xué)院主編.工程起重機(jī).北京：中國建筑工業(yè)出版社2 董剛、李建功主編.機(jī)械設(shè)計(jì).機(jī)械工業(yè)出版社3 機(jī)械設(shè)計(jì)手冊(cè).化學(xué)工業(yè)出版社（5冊(cè)）4 GB/T94621999 塔式起重機(jī)技術(shù)條件5 GB/T137521992 塔式起重機(jī)設(shè)計(jì)規(guī)范6 GB51441994 塔式起重機(jī)安全規(guī)程 7 邢靜忠ANSYS應(yīng)用實(shí)例與分析科學(xué)出版社2006 8 劉坤ANSYS有限元方法精解國防工業(yè)出版社2005 9GB/T94621999 塔式起重機(jī)設(shè)計(jì)條件 10 GB/T137521992 塔式起重機(jī)設(shè)計(jì)規(guī)范11 GB/T51441994 塔式起重機(jī)安全規(guī)程 12劉鴻文材料力學(xué)北京：高等教育出版社2002 13李柱，徐振高互換性與測(cè)量技術(shù)北京：高等教育出版社2002 14 張東升機(jī)械零件及建筑機(jī)械重慶：重慶大學(xué)出版社.200315 現(xiàn)行建筑機(jī)械規(guī)范大全北京：中國建筑工業(yè)出版社.199516 吳慶鳴，何小新工程機(jī)械設(shè)計(jì)武昌：武漢大學(xué)出版社.2006 17劉佩衡塔式起重機(jī)使用手冊(cè)北京：機(jī)械工業(yè)出版社.2002 18 張質(zhì)文，虞和謙等起重機(jī)設(shè)計(jì)手冊(cè)北京：中國鐵道出版社1997 19 顧迪民工程起重機(jī)北京：中國建筑工業(yè)出版社1988指導(dǎo)教師意見： 指導(dǎo)教師簽名： 日期：教研室意見：教研室主任簽名： 日期：系意見： 系領(lǐng)導(dǎo)簽名： 日期： 系蓋章Ocean Engineering 29 (2002) 14631477 Analysis of Wells turbine design parameters by numerical simulation of the OWC performance A. Brito-Melo, L.M.C. Gato * , A.J.N.A. Sarmento Mechanical Engineering Department, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal Received 22 May 2001; accepted 30 August 2001 Abstract This paper investigates by numerical simulation the influence of the Wells turbine aerody- namic design on the overall plant performance, as affected by the turbine peak efficiency and the range of flow rates within which the turbine can operate efficiently. The problem of match- ing the turbine to an oscillating water column (OWC) is illustrated by taking the wave climate and the OWC of the Azores power converter. The study was performed using a time-domain mathematical model based on linear water wave theory and on model experiments in a wave tank. Results are presented of numerical simulations considering several aerodynamic designs of the Wells turbine, with and without guide vanes, and with the use of a bypass pressure- relief valve. 2002 Elsevier Science Ltd. All rights reserved. Keywords: Wave energy; Oscillating water column; Equipment; Wells turbine 1. Introduction The Wells turbine has been the most commonly adopted solution to the air-to- electricity energy conversion problem in oscillating water column (OWC) wave energy converters. These essentially consist of a capture pneumatic chamber, open at the bottom front to the incident wave, a turbine and an electrical generator. The incident wave motion excites the oscillation of the internal free surface of the entrained water mass in the pneumatic chamber, which produces a low-pressure reci- * Corresponding author. Tel.: +351-21-841-7411; fax: +351-21-841-7398. E-mail address: lgatohidro1.ist.utl.pt (L.M.C. Gato). 0029-8018/02/$ - see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: S 00 29 -8018(01)00099-3 1464 A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 procating flow that drives the turbine. A few full-scale turbine prototypes have been built and installed in grid-connected power plants in European countries, e.g. the 500 kW Wells monoplane turbine with guide vanes installed in the Island of Pico, Azores (Falcao, 2000), and 2250 kW biplane contrarotating turbine of the LIMPET plant, at Islay, Scotland (Heath et al., 2000). The greatest challenges to designers of equipment for wave energy converters are the intrinsically oscillating nature and the random distribution of the wave energy resource. These features are absent or much less severe in other competing energy technologies. The air turbine in an OWC converter is subject to flow conditions (randomly reciprocating flow), which, with respect to efficiency, are much more demanding than in turbines in almost any other application. The Wells turbine, while reaching only a moderately high peak efficiency as compared with conventional tur- bines, can operate in reciprocating flow without the need of a rectifying valve system. The turbine, on the one hand, is required to extract energy from air whose flow rate, in each of the two directions, oscillates between zero and a maximum value, which in turn has an extremely large variation from wave to wave and with sea conditions. On the other hand, at fixed rotational speed, turbines in general, and Wells turbines in particular, are capable of operating with good efficiency only within a limited range of flow conditions around the peak efficiency point. The power output of Wells turbines is known to be low (or even negative) at small flow rates (the flow rate passes through zero twice in a wave cycle) and it drops sharply for flow rates above a critical value due to aerodynamic losses produced by rotor blade stalling. Therefore, the turbine is expected to perform poorly in very energetic sea-states or whenever violent wave peaks occur. Mounting a bypass pressure-relief valve on the top of the air chamber as proposed in the Azores plant may prevent this problem. The valve is controlled to limit the maximum pressure and suction in the chamber (depending on the turbine rotational speed) to prevent the instantaneous air flow rate through the turbine from exceeding the values above which aerodynamic stalling at the rotor blades would produce a severe fall in power output. Numerical simulations (Brito- Melo et al., 1996; Falcao and Justino, 1999) indicate that a reduction in turbine size and a substantial increase in the annual production of electrical energy might be achieved by the use of a bypass pressure-relief valve. Moreover, recent studies (theoretical and model testing) indicate that blade sections especially designed for Wells turbine rotors can significantly enlarge the range of flow rates within which the turbine operates efficiently and reduce aerodynamic losses under partially stalled flow conditions, in comparison with other blade designs which give a higher peak efficiency within a narrower range of flow rates through the turbine. This raises the question of whether, in view of the total annual produced electrical energy and taking into account the hydrodynamic performance of the OWC device, it is more appropri- ate to select a turbine aerodynamic design which allows an enlarged range of flow rates at which the turbine operates efficiently or whether it is better to adopt a turbine design which gives a higher peak efficiency value with a reduced range of flow rates at which the turbine operates efficiently. Furthermore, it is of interest to know to what extent this issue might be dependent on the use of a pressure-relief valve. The main objective of the present work is to investigate the influence of the Wells 1465A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 turbine aerodynamic design on the overall plant performance, as affected by the turbine peak efficiency and the range of flow rates within which the turbine can operate efficiently. Realistic characteristics are assumed for the turbine and the use of a bypass pressure-relief valve is also considered. Since the resulting pressure changes in the chamber are dependent on the turbine characteristics and the pressure- relief valve influences the turbine operation, the hydrodynamic process of energy extraction is also modified. The hydrodynamics of the conversion of wave energy into pneumatic energy is predicted by using a time-domain mathematical model based on linear water wave theory and on model experiments in a wave tank as described in Sarmento and Brito-Melo (1996). The conversion of pneumatic energy into electrical energy is predicted by a suitable computational model of the power take-off equipment based on the results extrapolated from aerodynamic tests on a scale-model and on empirical approximations for the generator losses (Brito-Melo et al., 1996). This paper presents the results of numerical simulations considering several aerodynamic designs of the Wells turbine, with and without guide vanes, and the use of the pressure-relief valve. The problem of matching the turbine to an OWC is illustrated by taking the wave climate and the OWC of the Azores wave power converter. 2. Wave-to-wire model 2.1. Plant operation The wave-to-wire model concerns the operation of an OWC equipped with a Wells turbine, a bypass valve of unlimited capacity and a variable speed turbo-generator, under a set of representative sea-state conditions. The Wells turbine is known to exhibit an approximately linear relationship between the turbine pressure drop p(t) and the flow rate q t (t). Then we may write the turbine characteristic as K H11005 p(t)/q t (t) H11005 p s (H9024)/q s (H9024), where p s (H9024), and q s (H9024) are maximum values of pressure and flow rate (prior to the onset of aerodynamic stall at the turbine rotor blades), which (for a given turbine) depend on the turbine rotational speed H9024. The use of a properly controlled bypass pressure-relief valve prevents the occurrence of stall at the turbine rotor blades. The valve is controlled to ensure that |p(t)|H11349p s (H9024). Then |q s (t)|H11349q s (H9024). The excess flow rate q v (t) passes through the valve to (or from) the atmosphere. The inertia of the rotating parts is assumed large enough so that rotational speed H9024 may be considered approximately constant over the time-intervals simulating a given sea-state (about 15 minutes). This allows H9024 to be optimized for each represen- tative record of the sea-state, in order to maximize the electrical energy production. The turbine rotational speed is allowed to vary between the synchronous speed of the generator and twice its value. Summing the product of the time-averaged electri- cal power output with the occurrence frequency for all data records gives the overall annual average electrical power output. 1466 A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 2.2. Hydrodynamic model The hydrodynamic model is based on the pressure model presented in Sarmento and Falcao (1985). According to the OWC performance description presented in Section 2.1, the mass balance across a control surface enclosing the pneumatic chamber is given by p(t) K H11001 q v (t) H11005 q(t)H11002 V 0 gP a dp(t) dt (1) where q(t) is the volume flow rate displaced by the free-surface inside the chamber, V 0 denotes the volume of the air in the chamber under undisturbed conditions, P a is the atmospheric pressure and g is the ratio of specific heats. As stated in Section 2.1, q v (t) H11005 0if|p(t)| H11021 p s (H9024) (i.e. when the valve is not operating). According to the linear water wave theory, the volume flow rate displaced by the free-surface inside the chamber may be decomposed as q(t) H11005 q d (t) H11001 q r (t), where q d (t) is the diffraction flow rate, due to incident wave action assuming the internal and the exter- nal free-surfaces at constant atmospheric pressure, and q r (t) is the radiation flow rate due only to the pressure oscillation p(t) in otherwise calm waters. Under the assump- tions of the linearized wave theory, we may apply the convolution theorem to obtain the solution of a linear problem in terms of an impulse response (Pipes and Harvill, 1970), as follows: q r (t) H11005 H20885 H11002H11009 t h r (tH11002t)pH11032(t)dt (2) where pH11032(t) is the time-derivative of the pressure inside the chamber and t represents a time-lag. The upper limit of the integral in Eq. (2) represents the present instant t because the process is causal (Cummins, 1962). The impulse response function h r (t) can be obtained from the hydrodynamic coefficients of the OWC computed with a numerical model, such as the WAMIT (Lee et al., 1996) or the AQUADYN- OWC (Brito-Melo et al., 1999), or by tank testing. Here we use an estimate of the impulse response function obtained in free-oscillation transient experiments from 1:35 scale testing of the Azores OWC wave power plant (see Sarmento and Brito- Melo, 1996, for details). Time series for the diffraction flow, q d (t), have also been obtained in energy extrac- tion experiments with the scaled model subject to a set of 44 sea-states representative of the Azores power plant site. In these experiments a device producing an equivalent air pressure drop simulated the turbine. The flow rate q t (t) could be obtained as a function of p(t) from the device calibration curve. The diffraction flow time-series for each of the 44 sea-states was estimated by solving Eq. (1) (with q v (t) H11005 0) using the pressure records from the energy extraction experiments, and the experimental estimate of h r (t) previously obtained in the transient experiments. 1467A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 2.3. Power take-off equipment The power take-off sub-model is based on results extrapolated from small-scale turbine tests (Gato et al., 1996; Webster and Gato, 1999a,b) and on empirical data for the turbine and generator losses (Brito-Melo et al., 1996). The average power at the turbine shaft for a period T is given by W s H11005 H9024 T H20885 0 T L(H9024,q t (t)H11002L m (H9024) dt (3) where L is the aerodynamically produced turbine-torque and L m the torque due to mechanical losses (especially bearing losses). For stall-free conditions, L is approxi- mated by a second-order polynomial. In order to provide the necessary performance data to study the matching of the power take-off equipment and the pneumatic chamber, the data from small-scale turbine tests are modified using a simple mean- line turbine flow analysis method to take into account the rotor solidity S and the hub-to-tip ratio. Ignoring the postponement of stall when the Reynolds number is increased, scale effects are taken into account by correcting the torque curve of the turbine model. This is done multiplying (dividing) the positive (negative) values of L by f H11005 0.8/0.706. This corrects the torque curve of the unswept NACA 0015 bladed rotor with guide-vanes to match a peak efficiency of h max H11005 0.80. For the preliminary design of the turbine a maximum blade tip speed of 160 ms H110021 is assumed. The average electrical power output is obtained by subtracting the generator losses from the average power at the turbine shaft. The model for the generator losses includes the Joule losses, the iron losses, the ventilation losses and the mechanical losses (Brito-Melo et al., 1996). 3. Results and discussion Experimental research on different types of rotor blades has been conducted recently to improve the aerodynamic performance of the Wells turbine (Raghunathan, 1995; Gato et al., 1996; Curran and Gato, 1997; Webster and Gato, 1999a,b). Among these types, we consider two turbine blade configurations, which may give a wider range of flow rates within which the turbine can operate with fairly good efficiency, in comparison with that of the more standard NACA 0015 unswept bladed turbine rotor: they are the backward-swept NACA 0015 blades (Webster and Gato, 1999a), Fig. 1, and the optimized HSIM-15-262123-1576 unswept blades (Gato and Hen- riques, 1996), Fig. 2. For comparison we take results for the NACA 0015 unswept blades (Gato et al., 1996). Figs. 3 and 4 show experimental results from unidirectional-flow small-scale test- ing at the IST rig (Webster and Gato, 1999a,b). Results presented in Figs. 3 and 4 refer to high-solidity Wells turbine rotors (rotor outer radius R H11005 0.295 m, constant chord c H11005 125 mm, rotor solidity S H11005 0.64, equipped with the blades referred to 1468 A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 Fig. 1. Rotor blade sweep angle. Fig. 2. The NACA 0015 and HSIM 15-262123-1576 sections. above, with and without guide vanes. The figures show, in dimensionless form, experimental results for the efficiency h H11005 LH9024/(q t p), pressure drop p H11005 p/(rH9024 2 R 2 ), and torque L H11005 L/(rH9024 2 R 5 ) as functions of the flow rate coefficient U* (r is the air density). Results in Fig. 3 for the turbines without guide vanes show that the NACA 0015 unswept rotor has h max H11005 0.583 at U H11005 0.114, and stalls at U H11005 0.21. The NACA 0015 30 backward-swept rotor has a lower h max H11005 0.583, with a lower flow rate for the onset of stall, U H11005 0.17, but without exhibiting the sharp decrease in the torque that occurs in the unswept rotor. Furthermore, under stall conditions, the torque of the swept rotor becomes negative at a much higher flow rate, U H11022 0.45, whereas for the unswept blades the efficiency becomes nega- tive for U H11022 0.3. The unswept HSIM bladed rotor shows a h max similar to that of the backward-swept rotor, but produces a soft progressive stall of the flow through the rotor blades, with notably higher efficiency for a wide range of flow rates after the onset of stall. Fig. 4 shows a corresponding plot for the same turbine rotors when equipped with a double row of guide vanes. The experimental results plotted in Fig. 4 show that the use of guide vanes increases h max for any of the above geometries, i.e. from 0.583 to 0.706, 0.551 to 0.613 and 0.553 to 0.669, for the NACA 0015 unswept and 1469A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 Fig. 3. Unswept and 30 backward-swept NACA 0015 and unswept HSIM bladed rotor turbines, without guide vanes: measured values of efficiency (a), pressure drop (b) and torque (c) against flow rate coef- ficient. 1470 A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 Fig. 4. Unswept and 30 backward-swept NACA 0015 and unswept HSIM bladed rotor turbines, with guide vanes: measured values of efficiency (a), pressure drop (b) and torque (c) against flow rate coef- ficient. 1471A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 backward-swept rotors and the HSIM unswept rotor, respectively. Furthermore, we find that the use of guide vanes narrows the range of flow rates within which the turbine works with positive torque. Table 1 summarizes the performance data for the six turbines, where U a and U b are the minimum and maximum flow rate coefficients respectively, at which the efficiency is nominally h H11005 0.5h max . Therefore, H9021H11005U a /U b and H9004H11005U a H11002U b give an indication of the operational range while (H9004p 0 /U ) h H11005 h max is the pressureflow ratio in the approximately rectilinear region. In the above performance comparison, constant overall solidity was assumed for the different turbine configurations. Results in Table 1 show that the rotor blade geometry has a remarkable influence on the turbine performance. In particular, some rotor geometries give a considerable wider range of flow rates within which the turbine operates efficiently, in comparison with others that have higher peak efficiency within a narrower range of flow rates. Figs. 57 plot the average electrical power output as given by the numerical simul- ation for the set of the 44 representative records of the wave climate for the Azores Plant site, taking into account the frequency of occurrence of each sea-state. The results give the turbine characteristic K for several values of the rated power W 0 H11005 p s q s . Table 2 indicates the values of the flow coefficient U s at which the different types of turbine rotor were designed and the bypass pressure-relief valve is actuated. 3.1. NACA 0015 unswept bladed rotor with and without guide vanes Fig. 5 presents the results of the numerical simulation to study the effect of the use of guide vanes with the NACA 0015 unswept bladed rotor. Fig. 5 shows that the use of guide vanes provides a significant increase in the average electrical power output, both with and without the presence of the bypass pressure-relief valve. The curves plotted in Figs. 3 and 4 for the unswept NACA 0015 rotor, with and without guide vanes, respectively, show that the turbine with guide vanes has h max H110150.72 Table 1 Peak efficiency, useful flow rate range and damping ratio for several turbine models (overall solidity S=0.64) Turbine rotor With guide vanes Without guide vanes NACA 0015 NACA 0015 HSIM NACA 0015 NACA 0015 HSIM unswept swept-back unswept unswept swept-back unswept h max 0.706 0.613 0.669 0.583 0.551 0.553 (U ) h H11005h max 0.124 0.137 0.154 0.114 0.129 0.131 U a 0.050 0.062 0.057 0.051 0.058 0.059 U b 0.197 0.209 0.275 0.251 0.232 0.360 H9021 0.254 0.297 0.207 0.203 0.250 0.164 H9004 0.147 0.147 0.218 0.200 0.174 0.301 (H9004p 0 /U ) h H11005h max 2.19 1.87 2.38 2.54 2.04 2.79 1472 A. Brito-Melo et al. / Ocean Engineering 29 (2002) 14631477 Fig. 5. Unswept NACA 0015 bladed rotor turbine with and without guide vanes working (a) with and (b) without the bypass valve: average electrical power conversion as a function of the turbine characteristic K, for several values of the turbine-rated power. whereas for the turbine without guide vanes