本文選題：離心泵作透平 + 變轉(zhuǎn)速��； 參考：《華南理工大學(xué)》2016年博士論文

【摘要】：能源發(fā)展面臨著需求壓力巨大、能源供給制約較多、能源生產(chǎn)和消費(fèi)對(duì)生態(tài)環(huán)境損害嚴(yán)重、能源技術(shù)水平總體落后等挑戰(zhàn)。當(dāng)前全球都在經(jīng)歷新一輪的能源技術(shù)革命,以綠色低碳為導(dǎo)向,節(jié)能高效的能源技術(shù)已上升到國(guó)家發(fā)展和安全的戰(zhàn)略高度。泵反轉(zhuǎn)作液力透平被稱為pump as turbine(PAT),這種能量回收裝置應(yīng)用于石油化工、冶金、煤炭以及廢水處理等行業(yè)的中,回收介質(zhì)中的余壓能量,達(dá)到節(jié)能降耗的效果。目前,在上述工業(yè)關(guān)鍵領(lǐng)域,幾乎全部采用進(jìn)口透平機(jī)組回收液體余壓能量,國(guó)內(nèi)制造商面臨的問題主要是回收率低和可靠性不高的問題。就工業(yè)應(yīng)用來講,著眼整個(gè)透平系統(tǒng),考量裝置運(yùn)行安全性的研究,尤其是系統(tǒng)的瞬態(tài)效應(yīng),包括變轉(zhuǎn)速的過渡過程,都是很有價(jià)值的議題。本文從內(nèi)在的科學(xué)問題出發(fā),針對(duì)泵作透平系統(tǒng)變轉(zhuǎn)速及過渡工況特性進(jìn)行研究,從透平的選型和性能預(yù)測(cè),到透平系統(tǒng)的搭建和參數(shù)匹配,從設(shè)計(jì)轉(zhuǎn)速工況到其它轉(zhuǎn)速工況,再到連貫的過渡工況,本文從理論、數(shù)值計(jì)算和試驗(yàn)等三個(gè)方面進(jìn)行了有針對(duì)性的研究。本文開展的研究工作如下:(1)PAT系統(tǒng)不同過程的試驗(yàn)和數(shù)值計(jì)算策略類比了工業(yè)測(cè)試和實(shí)驗(yàn)室研究用的離心泵作透平試驗(yàn)臺(tái)的特點(diǎn),針對(duì)PAT系統(tǒng)的穩(wěn)態(tài)、準(zhǔn)穩(wěn)態(tài)和過渡過程提出合理的試驗(yàn)方案,搭建了相應(yīng)的試驗(yàn)臺(tái)和控制系統(tǒng),成功實(shí)現(xiàn)了泵作透平瞬態(tài)過渡過程的性能測(cè)試和振動(dòng)測(cè)試等;對(duì)比了相同過渡工況下雷諾平均法和大渦模擬法的計(jì)算結(jié)果,在穩(wěn)態(tài)計(jì)算的基礎(chǔ)上,提出了較為完善的過渡態(tài)數(shù)值計(jì)算策略,通過CFX-CEL和User Function實(shí)現(xiàn)對(duì)不同轉(zhuǎn)速的定義,獲得過渡過程的PAT內(nèi)流和瞬變特征,并通過試驗(yàn)驗(yàn)證。(2)基于蝸殼和轉(zhuǎn)輪匹配理論的運(yùn)行工況點(diǎn)預(yù)測(cè)和PAT系統(tǒng)配置參照經(jīng)典一元離心泵葉輪和蝸殼的匹配性理論,通過理論分析推導(dǎo)了考慮了葉片出口滑移和有限葉片數(shù)效應(yīng)的透平轉(zhuǎn)輪特性方程,提出了PAT最優(yōu)工況點(diǎn)參數(shù)的預(yù)測(cè)公式和相應(yīng)的泵與透平性能換算公式,該式不以比轉(zhuǎn)速為變量,實(shí)例驗(yàn)證其具有較高的精度;研究了不同的負(fù)載泵對(duì)PAT系統(tǒng)的影響,探討了高效PAT系統(tǒng)中PAT和負(fù)載的參數(shù)匹配特征,二者的最佳參數(shù)范圍為/0.4~0.6T PQ Q=,/3.57~4.35T PH H=,揭示了變轉(zhuǎn)速過程中負(fù)載和系統(tǒng)的性能特性。(3)恒定轉(zhuǎn)速下PAT內(nèi)流和外特性借助CFD研究了設(shè)計(jì)轉(zhuǎn)速下PAT的內(nèi)流場(chǎng)和外特性。重點(diǎn)探究了非定常工況下PAT流動(dòng)域內(nèi)的流場(chǎng)變遷、流量分配和水力載荷等問題,提出了內(nèi)流場(chǎng)流量分析法,直觀地揭示了PAT計(jì)算中簡(jiǎn)化前后泵腔誤差較大的內(nèi)流場(chǎng)機(jī)理,即前后泵腔和環(huán)形間隙的顯著分流和流動(dòng)損耗,發(fā)現(xiàn)流體在一些固定區(qū)域由環(huán)形區(qū)域進(jìn)入兩側(cè)泵腔,而在另一些區(qū)域流回環(huán)形空間;監(jiān)測(cè)了拉格朗日和歐拉觀點(diǎn)下的轉(zhuǎn)輪瞬時(shí)流量信息,一定程度上量化了流場(chǎng)的演變特征,為相關(guān)研究提供了借鑒;研究了設(shè)計(jì)轉(zhuǎn)速下不同工況的水力損失分布,轉(zhuǎn)輪水力載荷和壓力脈動(dòng),以及軸向力和徑向力等特征。(4)變轉(zhuǎn)速下PAT的內(nèi)流和外特性探討了PAT的轉(zhuǎn)速特性曲線和不同BEP點(diǎn)(最佳效率點(diǎn))的內(nèi)流場(chǎng)分布,發(fā)現(xiàn)不同轉(zhuǎn)速和工況點(diǎn)下PAT的運(yùn)行效率相差很大,研究透平系統(tǒng)變轉(zhuǎn)速運(yùn)行的一般規(guī)律具有顯著的效益;選取了三個(gè)典型的不同轉(zhuǎn)速BEP工況點(diǎn),研究了其流場(chǎng)差異、葉片載荷、徑向力、軸向力和水力脈動(dòng)等參數(shù)的變化特征,即不同BEP點(diǎn)水力穩(wěn)定性研究。結(jié)果表明,PAT的徑向力和軸向力在幅值上總體上遠(yuǎn)小于水泵。隨著轉(zhuǎn)速的增加,軸向力逐漸增大且脈動(dòng)加劇,PAT偏離設(shè)計(jì)工況和轉(zhuǎn)速運(yùn)行時(shí)蝸殼內(nèi)壓力脈動(dòng)幅值有所增加,振動(dòng)試驗(yàn)與壓力脈動(dòng)計(jì)算結(jié)果相一致。(5)PAT系統(tǒng)過渡過程下的瞬變特性研究分析了廣義歐拉方程在水力機(jī)械中的應(yīng)用,發(fā)現(xiàn)其不能直接用于計(jì)算PAT過渡過程的瞬態(tài)揚(yáng)程;對(duì)PAT系統(tǒng)的轉(zhuǎn)子進(jìn)行了整體轉(zhuǎn)動(dòng)分析,確立了過渡過程流動(dòng)域瞬態(tài)計(jì)算的整體策略;數(shù)值計(jì)算了恒壓加減速和恒流加減速四個(gè)類型下的PAT瞬態(tài)流場(chǎng),分析了該過程PAT的瞬態(tài)性能參數(shù)變化和流場(chǎng)演變特征,發(fā)現(xiàn)準(zhǔn)穩(wěn)態(tài)計(jì)算的數(shù)值大于過渡態(tài)計(jì)算和試驗(yàn)數(shù)值,過渡過程的計(jì)算值略大于試驗(yàn)值,計(jì)算與試驗(yàn)吻合較好;通過PAT內(nèi)流場(chǎng)分析,發(fā)現(xiàn)過渡過程中流線分布和葉道渦的位置有顯著的變化,流場(chǎng)最紊亂的時(shí)刻發(fā)生在過渡工況的起始時(shí)刻;通過非線性的轉(zhuǎn)速函數(shù)優(yōu)化了過渡過程的計(jì)算,獲得了PAT和負(fù)載同步的計(jì)算結(jié)果,提升了過渡過程數(shù)值計(jì)算的精度;在特定的過渡工況計(jì)算模型中加入空化模型,獲得了顯著的汽蝕效應(yīng),證實(shí)了二者之間的相關(guān)性。
[Abstract]:Energy development is facing the challenges of huge demand pressure, more constraints of energy supply, serious energy production and consumption, serious damage to the ecological environment and the overall backward energy technology level. The current world is experiencing a new round of energy technology revolution, guided by green low-carbon, and energy saving and high efficiency energy technology has risen to national development and security. The hydraulic turbine is called pump as turbine (PAT). This energy recovery device is applied to the petrochemical, metallurgical, coal and wastewater treatment industries, and the residual pressure energy in the recycled medium can achieve the effect of energy saving and consumption reduction. At present, almost all of the key fields in the industry are used for the import of the imported turbine unit. The problem that the domestic manufacturers face is the problem of low recovery and low reliability. In terms of industrial applications, the research on the safety of the whole turbine system and the operation of the equipment, especially the transient effect of the system, including the transition process of the variable speed, is a very valuable issue. This article from the internal scientific problem. According to the research on the variable speed and transition condition characteristics of the turbine system, from the type selection and performance prediction of the turbine to the structure of the turbine and the matching of the parameters, from the design of the rotational speed to the other speed conditions, and then to the coherent transition condition, this paper has carried on the pertinent research from three aspects, the theory, the numerical calculation and the experiment. The research work of this paper is as follows: (1) the characteristics of the centrifugal pump used in the industrial test and the laboratory research are analogous to the characteristics of the centrifugal pump used in the industrial test and laboratory research, and the reasonable test scheme for the steady state, the quasi steady state and the transition process of the PAT system is proposed, and the corresponding test bed and control system are set up in the PAT system. The performance test and vibration test of the pump as the transient transition process are realized, and the results of the Reynolds mean method and the large eddy simulation method are compared under the same transition conditions. On the basis of the steady state calculation, a more perfect transition state numerical calculation strategy is put forward, and the definition of different rotational speeds is realized through CFX-CEL and User Function. The PAT internal flow and transient characteristics of the transition process are obtained and verified by experiments. (2) based on the operating condition point prediction of the worm shell and wheel matching theory and the matching theory of the classic one element centrifugal pump impeller and the volute with the PAT system configuration, the turbine runner with the effect of blade slip and finite blade number is derived by theoretical analysis. The characteristic equation, the prediction formula of PAT optimal operating point parameters and the corresponding formula of pump and turbine performance are put forward. This formula does not use the specific speed as the variable, the example verifies its high precision. The influence of different load pumps on the PAT system is studied, and the parameters matching characteristics of the PAT and load in the high efficiency PAT system are discussed, and the best two are the best. The parameter range is /0.4~0.6T PQ Q= and /3.57~4.35T PH H=, which reveals the performance characteristics of the load and the system in the process of variable speed. (3) the internal flow and external characteristics of PAT at design speed are studied with CFD at constant speed at the constant speed. The flow field, flow distribution and hydraulic load in the unsteady state of the PAT flow field are focused on. The flow flow analysis method of internal flow field is put forward to reveal the internal flow mechanism of the large error of the pump cavity before and after the simplified PAT calculation, that is, the significant shunt and flow loss of the front and back pump cavity and the annular gap, and find that the fluid enters the two side pump chambers from the annular region in some fixed areas and flows back to the annular space in some other regions; The instantaneous flow information of the runner in Lagrange and Euler's point of view quantifies the evolution characteristics of the flow field to some extent and provides reference for the related research. The hydraulic loss distribution in different working conditions at the design speed, the hydraulic load and pressure pulsation of the wheel, and the axial force and radial force are studied. (4) the internal flow of PAT under the variable speed and the internal flow of the rotating speed. The external characteristics of the PAT speed characteristic curve and the internal flow field distribution of different BEP points (the best efficiency point) are discussed. It is found that the operating efficiency of PAT at different rotational speeds and working conditions is very different. The general rule of the variable speed operation of the turbine system has significant benefits, and three different speed BEP operating points are selected, and the flow field difference is studied. The variation characteristics of the parameters such as the load of the blade, the radial force, the axial force and the hydraulic pulsation, that is, the hydraulic stability of different BEP points. The results show that the radial force and the axial force of the PAT are generally far smaller than the water pump. With the increase of the speed, the axial force increases gradually and the pulsation increases, and the PAT deviates from the design condition and the speed of the spiral case. The amplitude of pressure fluctuation is increased, and the vibration test is in agreement with the calculation results of pressure pulsation. (5) the transient characteristics of the PAT system under the transition process are studied and analyzed in the application of the generalized Euler equation in the hydraulic machinery. It is found that it can not be used directly to calculate the transient head of the PAT transition process; the whole rotation analysis of the rotor of the PAT system is true. The overall strategy of transient calculation in the flow field of the transition process is established. The PAT transient flow field under four types of constant pressure plus deceleration and constant current plus deceleration is numerically calculated. The transient performance parameters and the flow field evolution characteristics of the PAT are analyzed. It is found that the numerical value of the quasi steady state calculation is greater than the transition state calculation and the experimental values, and the calculation values of the transition process are calculated. It is a little bigger than the test value, and the calculation is in good agreement with the test. Through the analysis of the flow field in PAT, it is found that the distribution of streamline and the position of Ye Daowo in the transition process have a significant change, the most disordered time of the flow field occurs at the beginning of the transition condition, and the calculation of the transition process is optimized through the nonlinear rotational speed function, and the synchronization of the PAT and the load is obtained. The calculation results improve the accuracy of the numerical calculation of the transition process, and the cavitation effect is obtained by adding the cavitation model in the specific transition working model, which confirms the correlation between the two.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TH311

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