本文關(guān)鍵詞： 渦輪增壓 離心壓氣機(jī) 有葉擴(kuò)壓器 穩(wěn)定性 畸變　出處：《清華大學(xué)》2014年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：內(nèi)燃機(jī)節(jié)能減排的需求及日益嚴(yán)格的排放法規(guī)要求渦輪增壓離心壓氣機(jī)具有寬廣的穩(wěn)定工作范圍。渦輪增壓離心壓氣機(jī)的流動(dòng)穩(wěn)定性成為發(fā)展渦輪增壓技術(shù)的主要瓶頸之一。 渦輪增壓離心壓氣機(jī)具有周向非對(duì)稱(chēng)的蝸殼結(jié)構(gòu)，導(dǎo)致離心壓氣機(jī)的周向流場(chǎng)結(jié)構(gòu)在非設(shè)計(jì)工況下不均勻；傳統(tǒng)流動(dòng)控制措施認(rèn)為離心壓氣機(jī)為軸對(duì)稱(chēng)結(jié)構(gòu)，忽略了此流場(chǎng)結(jié)構(gòu)非對(duì)稱(chēng)性。清華大學(xué)基于渦輪增壓離心壓氣機(jī)固有的非對(duì)稱(chēng)流場(chǎng)特征，提出了“非對(duì)稱(chēng)流動(dòng)控制”思想。擴(kuò)壓器對(duì)渦輪增壓離心壓氣機(jī)穩(wěn)定性具有重要影響，本論文基于“非對(duì)稱(chēng)流動(dòng)控制”思想，探索非對(duì)稱(chēng)有葉擴(kuò)壓器擴(kuò)穩(wěn)新方法，，以期實(shí)現(xiàn)離心壓氣機(jī)穩(wěn)定工作范圍的大幅度拓寬。 為方便改變出口畸變的參數(shù)，定量分析擴(kuò)壓器出口壓力畸變對(duì)離心壓氣機(jī)性能影響，本文用周向非均勻壓力分布作為出口邊界條件代替蝸殼建立了畸變模型，并證明了畸變模型可以用來(lái)分析蝸殼產(chǎn)生的畸變對(duì)離心壓氣機(jī)性能的影響�；诨兡Ｐ�，通過(guò)給定出口壓力畸變不同的幅值研究了壓力畸變?cè)陔x心壓氣機(jī)中的傳播規(guī)律及壓力畸變幅值對(duì)離心壓氣機(jī)壓比、效率和穩(wěn)定工作范圍的影響。結(jié)果表明出口壓力畸變會(huì)降低離心壓氣機(jī)的壓比、效率和穩(wěn)定工作范圍，隨著畸變幅值的增加，離心壓氣機(jī)性能降低增加。擴(kuò)壓器出口壓力畸變能夠傳播到上游的擴(kuò)壓器和葉輪，導(dǎo)致部分流道率先發(fā)生失速，進(jìn)而引發(fā)整個(gè)離心壓氣機(jī)喘振，隨著出口壓力畸變振幅的增加，率先發(fā)生失速時(shí)的流量也會(huì)增加，導(dǎo)致離心壓氣機(jī)穩(wěn)定工作范圍降低，從而揭示了局部失速誘發(fā)系統(tǒng)提前喘振的物理機(jī)理。 基于蝸殼導(dǎo)致的壓力畸變對(duì)離心壓氣機(jī)性能影響機(jī)理，突破目前國(guó)際上離心壓氣機(jī)的有葉擴(kuò)壓器均為對(duì)稱(chēng)分布的傳統(tǒng)，首次提出并發(fā)展了“非對(duì)稱(chēng)有葉擴(kuò)壓器”流動(dòng)控制新方法：通過(guò)分析蝸殼引起的擴(kuò)壓器出口的壓力畸變，判斷率先發(fā)生失速的區(qū)域，通過(guò)有葉擴(kuò)壓器葉片安裝角或稠度非對(duì)稱(chēng)布置，抑制此區(qū)域的流動(dòng)分離，從而提高有葉擴(kuò)壓器離心壓氣機(jī)的穩(wěn)定工作范圍。根據(jù)此方法設(shè)計(jì)了非對(duì)稱(chēng)有葉擴(kuò)壓器改型方案，并進(jìn)行了仿真和試驗(yàn)驗(yàn)證。仿真結(jié)果表明：非對(duì)稱(chēng)有葉擴(kuò)壓器葉片安裝角或稠度分布能夠抑制蝸殼畸變導(dǎo)致的有葉擴(kuò)壓器局部失速，從而拓寬有葉擴(kuò)壓器離心壓氣機(jī)的穩(wěn)定工作范圍。試驗(yàn)結(jié)果表明：轉(zhuǎn)速為90%時(shí)，離心壓氣機(jī)的穩(wěn)定工作范圍由25.4%提高到33.1%。
[Abstract]:The demand for energy saving and emission reduction of internal combustion engines and the increasingly stringent emission regulations require a wide range of stable operation for turbocharged centrifugal compressors. The flow stability of turbocharged centrifugal compressors has become one of the main bottlenecks in the development of turbocharging technology. The circumferential asymmetric volute structure of the turbocharged centrifugal compressor leads to the non-uniformity of the circumferential flow field of the centrifugal compressor under non-design conditions, and the conventional flow control measures consider the centrifugal compressor to be an axisymmetric structure. The asymmetry of the flow field structure is ignored. Based on the inherent asymmetric flow field characteristics of the turbocharged centrifugal compressor, Tsinghua University puts forward the idea of "asymmetric flow control". The diffuser has an important effect on the stability of the turbocharged centrifugal compressor. Based on the idea of "asymmetric flow control", this paper explores a new method for stabilizing the asymmetric blade diffuser in order to widen the working range of centrifugal compressor by a large margin. In order to change the parameters of outlet distortion and quantitatively analyze the influence of diffuser outlet pressure distortion on the performance of centrifugal compressor, a distortion model is established in this paper, in which the circumferential non-uniform pressure distribution is used as the outlet boundary condition instead of the volute case. It is proved that the distortion model can be used to analyze the effect of the distortion produced by the volute on the performance of centrifugal compressor. The propagation law of pressure distortion in centrifugal compressor and the pressure ratio of pressure distortion to centrifugal compressor are studied by giving different amplitudes of outlet pressure distortion. The results show that the pressure ratio of centrifugal compressor, the efficiency and the working range of centrifugal compressor will be decreased with the increase of distortion amplitude. The pressure distortion at the outlet of the diffuser can propagate to the diffuser and impeller upstream, which leads to the first stall in some of the flow channels, which leads to the surge of the whole centrifugal compressor, and with the increase of the amplitude of the pressure distortion at the outlet, The flow rate will also increase when the first stall occurs, which leads to the decrease of the stable working range of the centrifugal compressor, thus revealing the physical mechanism of the local stall induced system surge ahead of time. Based on the influence mechanism of pressure distortion caused by volute on the performance of centrifugal compressor, this paper breaks through the tradition that the vaned diffuser of centrifugal compressor in the world is symmetrical distributed at present. For the first time, a new flow control method for "asymmetric vaned diffuser" is proposed and developed. By analyzing the pressure distortion at the outlet of the diffuser caused by the volute, the region where the stall occurs first is judged. The flow separation in this area is restrained by asymmetric arrangement of the blade mounting angle or consistency of the blade diffuser, thus increasing the stable working range of the centrifugal compressor of the blade diffuser. According to this method, the modification scheme of the asymmetric blade diffuser is designed. The simulation results show that the distribution of blade mounting angle or consistency of asymmetric blade diffuser can restrain the local stall of blade diffuser caused by volute distortion. The experimental results show that the stable working range of centrifugal compressor increases from 25.4% to 33.1 when the rotating speed is 90.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TH452

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本文編號(hào)：1495836