本文選題：有機工質朗肯循環(huán)　切入點：向心透平　出處：《華北電力大學》2017年碩士論文

【摘要】：有機工質朗肯循環(huán)(ORC)發(fā)電技術在回收工業(yè)廢熱、利用太陽能和地熱能等方面發(fā)揮了重要作用。而向心透平作為低溫余熱發(fā)電技術循環(huán)系統(tǒng)中的重要部件,有著較小的余速損失和流動損失,結構簡單和運行范圍較寬等優(yōu)點受到越來越多的關注。本文以ORC向心透平為研究對象,對其設計方法和流動特性進行研究,主要研究內容如下:以環(huán)己烷為工質,對200kW向心透平進行熱力設計,確定靜葉和動葉的幾何氣動參數(shù)和結構尺寸。采用ANSYS-CFX對透平進行數(shù)值計算,分析透平的整體性能和內部的流動情況。結果表明,所設計的向心透平熱力參數(shù)與數(shù)值模擬結果基本吻合,所有參數(shù)誤差都控制在3%之內,驗證了設計方法的正確性,同時獲得了較高的透平效率;模擬結果能真實地反映透平內部流動特性。透平整體性能較好,壓降分布和馬赫數(shù)分布較為合理,沒有出現(xiàn)較大的流動分離現(xiàn)象。研究了有機工質向心透平內流動特性,針對ORC向心透平靜葉柵,分析了工質在靜葉柵內的流動損失機理和主要損失分布,分析了下上端壁流動分布和葉柵通道內的各種渦系的表現(xiàn)形式,給出了總壓損失系數(shù)的分布規(guī)律。數(shù)值結果表明,葉柵通道存在壓力面和吸力面之間的橫向流動,但通道渦并沒有形成,通道渦并不是ORC向心透平靜葉柵內二次流渦流形式中的重要渦系結構;主要總壓損失在軸向弦長方向集中在葉柵后40%流道,在葉高方向集中在上下端壁,在周向方向聚集在吸力面附近。針對動葉進行了優(yōu)化設計,通過改變形狀設計參數(shù)來得到葉輪不同扭曲變化規(guī)律,分析動葉輪扭曲規(guī)律對透平效率的影響。數(shù)值計算結果表明,葉輪的扭曲程度會影響葉輪流道形狀和出口氣流與軸向的夾角,不同的葉輪扭曲規(guī)律使透平輪周效率的最大變化范圍達到了2.44%,是葉輪結構優(yōu)化設計的重要影響因素。研究了不同工況下透平入口溫度、出口壓力、轉速對透平效率性能和通流性能的影響。結果表明,在設計工況點下,各個變量對透平效率和流量的影響最小,并且效率能保持在較高水平。在三個變化因素中,轉速對透平效率的影響最大,效率最大變化值達到了10.88%。在120%轉速和120%背壓情況下流量變化范圍較大。整體來看,有機工質向心透平性能受變工況的影響較大,控制好合理的進出口參數(shù)和轉速水平對透平的高效運行至關重要。
[Abstract]:The organic refrigerant Rankine cycle (ORC) power generation technology plays an important role in recovering industrial waste heat, utilizing solar energy and geothermal energy, etc. The centripetal turbine is an important component in the circulating system of low-temperature waste heat power generation technology. More and more attention has been paid to the advantages of small residual velocity loss and flow loss, simple structure and wide range of operation. In this paper, the design method and flow characteristics of ORC centripetal turbine are studied. The main research contents are as follows: with cyclohexane as working medium, the thermodynamic design of 200kW centripetal turbine is carried out, and the geometric aerodynamic parameters and structural dimensions of static and moving blades are determined. The turbine is numerically calculated by ANSYS-CFX. The overall performance and internal flow of the turbine are analyzed. The results show that the thermodynamic parameters of the designed centripetal turbine are in good agreement with the numerical simulation results, and the errors of all the parameters are controlled within 3%, which verifies the correctness of the design method. At the same time, a higher turbine efficiency is obtained, and the simulation results can truly reflect the internal flow characteristics of the turbine. The overall performance of the turbine is better, and the pressure drop distribution and Mach number distribution are more reasonable. In this paper, the flow characteristics of organic working fluid in the centripetal turbine are studied. The flow loss mechanism and main loss distribution of the working fluid in the static cascade are analyzed according to the ORC centripetal transparent calm cascade. In this paper, the flow distribution of the upper wall and the form of vortex system in the cascade channel are analyzed, and the distribution law of the total pressure loss coefficient is given. The numerical results show that there is a transverse flow between the pressure surface and the suction surface in the cascade channel. However, the channel vortex was not formed, and the channel vortex was not an important vortex system in the form of secondary vortex in the ORC concentric calm cascade, and the main total pressure loss was concentrated in the axial chord length direction in the 40% channel behind the cascade, and in the upper and lower end wall in the high direction of the blade. The optimum design of moving blade is carried out in the vicinity of the suction surface in the circumferential direction. By changing the shape design parameters, the different distortion law of the impeller is obtained, and the influence of the twist law on the turbine efficiency is analyzed. The numerical results show that the influence of the twisting law of the impeller on the turbine efficiency is obtained by changing the shape design parameters. The twist of the impeller affects the shape of the impeller passage and the angle between the outlet airflow and the axial flow. The maximum variation range of turbomachinery circumference efficiency is 2.44, which is an important factor in the optimization design of impeller structure. The turbine inlet temperature and outlet pressure under different working conditions are studied. The effect of rotating speed on turbine efficiency and flow performance. The results show that, at the design working conditions, each variable has the least effect on turbine efficiency and flow rate, and the efficiency can be maintained at a high level. The effect of rotating speed on turbine efficiency is the greatest, and the maximum variation value of efficiency reaches 10.88. The flow rate varies greatly under 120% rotating speed and 120% back pressure. Overall, the performance of organic working fluid centripetal turbine is greatly affected by variable working conditions. It is very important to control the reasonable import and export parameters and speed level for the efficient operation of the turbine.
【學位授予單位】：華北電力大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM617

【參考文獻】

相關期刊論文 前10條

1 邵帥;鄧清華;豐鎮(zhèn)平;;向心透平初始設計自動進化尋優(yōu)方法與變工況性能預測模型[J];工程熱物理學報;2016年01期

2 王慧;李水蓮;魏新利;;向心透平葉輪子午面形狀等腰梯形設計法[J];機械科學與技術;2015年05期

3 于超;徐進良;苗政;楊緒飛;;窄點溫差及工質物性對跨臨界有機朗肯循環(huán)性能的影響[J];化工學報;2014年12期

4 韓中合;杜燕;王智;;有機朗肯循環(huán)低溫余熱回收系統(tǒng)的工質選擇[J];化工進展;2014年09期

5 夏立軍;裴剛;李晶;胡名科;季杰;;ORC系統(tǒng)小型渦輪不同轉速下的性能分析[J];化工學報;2014年11期

6 劉超;徐進良;陳奇成;苗政;;低溫跨臨界有機朗肯循環(huán)工質篩選[J];中國電機工程學報;2013年23期

7 李艷;顧春偉;;高膨脹比有機工質向心透平氣動優(yōu)化研究[J];工程熱物理學報;2013年07期

8 李艷;李海波;顧春偉;;有機工質向心透平氣動設計與變工況性能預測[J];工程熱物理學報;2013年01期

9 高怡秋;李一興;王暉;;超音速噴嘴變工況性能分析與試驗研究[J];熱能動力工程;2012年04期

10 鄢景;楊自春;;動力渦輪有冠及無冠動葉柵頂部二次流的數(shù)值分析[J];燃氣輪機技術;2011年02期

相關碩士學位論文 前5條

1 劉博文;有機工質向心透平膨脹機的性能研究[D];鄭州大學;2015年

2 吳偉銘;有機朗肯循環(huán)向心透平內流特性研究與優(yōu)化設計[D];華北電力大學;2015年

3 彭林斌;能量回收向心透平設計及內部流動分析[D];上海交通大學;2010年

4 林奇燕;透平級葉柵流動性能分析[D];哈爾濱工程大學;2007年

5 張鵬剛;微型燃氣輪機向心透平氣動性能的數(shù)值研究[D];大連理工大學;2005年

，

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