本文選題：有機朗肯循環(huán)　切入點：流動壓降　出處：《湘潭大學》2017年碩士論文　論文類型：學位論文

【摘要】：有機朗肯循環(huán)(Organic Rankine Cycle,簡稱ORC)發(fā)電技術是一種高效低品位余熱回收技術,具有結構簡單、熱效率高,蒸發(fā)壓力相對較低等優(yōu)點。本文針對ORC發(fā)電技術,在考慮流動壓降下分析運行參數(shù)對系統(tǒng)整體性能的影響,開展蒸發(fā)器運行參數(shù)和結構參數(shù)的多目標優(yōu)化,該研究對ORC發(fā)電技術的工業(yè)應用有一定的指導作用。具體內容和結論如下:1)建立ORC系統(tǒng)流動壓降計算模型與系統(tǒng)熱力分析模型,根據(jù)給定的初始參數(shù)對系統(tǒng)蒸發(fā)器和冷凝器進行設計,得到翅片管式蒸發(fā)器的管長為159.6m、換熱面積為46.26m~2,板式冷凝器的板片數(shù)為57、換熱面積為27.58m~2;依據(jù)ORC系統(tǒng)工質篩選原則,選取R245fa、R123、R600a、R141b、R134a和R236ea等六種常用循環(huán)工質。在此基礎上,利用文獻結果驗證了模型的可靠性。2)研究運行參數(shù)(蒸發(fā)壓力、過熱度、節(jié)點溫差)和熱源溫度對流動壓降的影響規(guī)律,并以凈輸出功、熱效率、?效率、熱回收率、不可逆損失為評價指標,對比分析流動壓降對ORC系統(tǒng)性能的影響規(guī)律。結果表明:ORC系統(tǒng)的流動壓降主要由蒸發(fā)器壓降組成,且蒸發(fā)壓力是影響系統(tǒng)壓降的主要因素�？紤]流動壓降下,蒸發(fā)壓力低于0.8MPa會導致系統(tǒng)各性能指標的降幅增大。對于干工質,節(jié)點溫差與過熱度對流動壓降的影響較小,不同節(jié)點溫差下流動壓降對系統(tǒng)性能的影響小于10%;流動壓降隨著熱源溫度的升高而增大。此外,工質是影響系統(tǒng)流動壓降與系統(tǒng)性能的重要因素,幾種工質中,R141b和R245fa為最佳工質。3)以ORC系統(tǒng)的流動壓降、凈輸出功、熱效率和熱回收率為優(yōu)化目標,以蒸發(fā)器的熱力參數(shù)(蒸發(fā)壓力、過熱度、節(jié)點溫差)、蒸發(fā)器結構參數(shù)(換熱管的管長、單排管子數(shù)、翅片高度、翅片厚度和翅片間距)為設計變量,采用模擬退火優(yōu)化算法對ORC系統(tǒng)蒸發(fā)器進行優(yōu)化設計,分析蒸發(fā)器熱力參數(shù)和結構參數(shù)對ORC系統(tǒng)性能的影響規(guī)律。結果表明:系統(tǒng)各性能指標之間存在博弈與對立現(xiàn)象,蒸發(fā)器熱力參數(shù)中蒸發(fā)壓力對目標函數(shù)值的影響最大,優(yōu)化條件下R245fa的最佳蒸發(fā)壓力為2.5MPa;蒸發(fā)器結構參數(shù)中,翅片結構是影響系統(tǒng)熱力性能的重要因素,而換熱管布置方式對系統(tǒng)熱力性能的影響基本可以忽略。對于R245fa,優(yōu)化后的翅片結構參數(shù)為翅片高度34mm、翅片厚度7.3mm、翅片間距3.5mm。
[Abstract]:Organic Rankine cycle (ORC) power generation technology is an efficient and low grade waste heat recovery technology, which has the advantages of simple structure, high thermal efficiency and relatively low evaporation pressure. Considering the flow pressure drop, the influence of operation parameters on the overall performance of the system is analyzed, and the multi-objective optimization of evaporator operating parameters and structural parameters is carried out. The research can be used to guide the industrial application of ORC power generation technology. The specific contents and conclusions are as follows: 1) the flow pressure drop calculation model of ORC system and the thermodynamic analysis model of ORC system are established. According to the design of system evaporator and condenser based on the given initial parameters, the tube length of finned tube evaporator is 159.6 m, the heat transfer area is 46.26 mm2, the plate number of plate condenser is 57, and the heat transfer area is 27.58 m2.According to the working medium screening principle of ORC system, Six commonly used circulating working fluids, R245faa R125faan R123AU R141bP134a and R236ea, are selected. On this basis, the reliability of the model is verified by using the results of literature. The effects of operating parameters (evaporation pressure, superheat degree, node temperature difference) and heat source temperature on the flow pressure drop are studied. And with the net output work, thermal efficiency? Efficiency, thermal recovery and irreversible loss are the evaluation indexes. The effect of flow pressure drop on the performance of ORC system is compared and analyzed. The results show that the flow pressure drop of ORC system is mainly composed of evaporator pressure drop. The evaporation pressure is the main factor affecting the pressure drop of the system. Considering the flow pressure drop, when the evaporation pressure is lower than 0.8 MPA, the decrease of the system performance will increase. For the dry working fluid, the effect of node temperature difference and superheat on the flow pressure drop is small. The effect of flow pressure drop on system performance is less than 10 under different node temperature differences, and the flow pressure drop increases with the increase of heat source temperature. In addition, the working fluid is an important factor affecting the system flow pressure drop and system performance. R141b and R245fa are the best working medium. 3) with the flow pressure drop, net output work, thermal efficiency and thermal recovery of ORC system as the optimization objectives, the thermodynamic parameters of evaporator (evaporation pressure, superheat degree, etc. The parameters of evaporator structure (tube length, pipe number, fin height, fin thickness and fin spacing) are used as design variables. Simulated annealing optimization algorithm is used to optimize the design of evaporator in ORC system. The influence of thermodynamic parameters and structural parameters of evaporator on the performance of ORC system is analyzed. The results show that there is a game and opposition phenomenon among the performance indexes of the system, and the evaporation pressure has the greatest influence on the objective function value of the thermodynamic parameters of the evaporator. The optimum evaporation pressure of R245fa is 2.5 MPA, and the fin structure is an important factor affecting the thermodynamic performance of the evaporator. For R245 faa, the optimized fin structure parameters are fin height 34mm, fin thickness 7.3mm, fin spacing 3.5mm.
【學位授予單位】：湘潭大學
【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 王華榮;徐進良;;采用BP-GA算法的有機朗肯循環(huán)多目標優(yōu)化[J];中國電機工程學報;2016年12期

2 王慧;馬新靈;孟祥睿;魏新利;;工質流量對ORC低溫余熱發(fā)電系統(tǒng)性能的影響[J];化工學報;2015年10期

3 魏新利;閆艷偉;馬新靈;孟祥睿;李明輝;;有機朗肯循環(huán)系統(tǒng)蒸發(fā)器的性能研究[J];鄭州大學學報(工學版);2015年04期

4 鄧立生;黃宏宇;何兆紅;z錒夂，

本文編號：1608399