本文選題：葉頂間隙氣流力 + 密封力��； 參考：《華中科技大學(xué)》2011年碩士論文

【摘要】：隨著各國經(jīng)濟(jì)的快速發(fā)展,用電量的需求也極具增加。但是作為發(fā)電主要機(jī)組的火力發(fā)電,其必需的煤炭等不可再生資源的儲(chǔ)存量卻日漸減少。因此,研制、生產(chǎn)和發(fā)展節(jié)能的大型汽輪機(jī)組成為火力發(fā)電的必然趨勢。然而,隨著汽輪機(jī)蒸汽參數(shù)的不斷提高,產(chǎn)生的氣流激振力也隨之增大,而且會(huì)有繼續(xù)嚴(yán)重的發(fā)展趨勢,最終影響汽輪機(jī)的安全運(yùn)行。因此,研究轉(zhuǎn)子在氣流力作用下的運(yùn)動(dòng)特性也越來越重要。 本文首先介紹了引發(fā)氣流激振的兩種主要?dú)饬髁?密封力和由葉輪偏心引起的葉頂間隙氣流力。并且分別建立了兩種氣流力的模型,以及轉(zhuǎn)子模型。然后以Matlab為主要的計(jì)算工具,對兩種氣流力作用下的轉(zhuǎn)子動(dòng)力學(xué)方程進(jìn)行了數(shù)值計(jì)算。 本文主要由理論分析轉(zhuǎn)子穩(wěn)定性和數(shù)值計(jì)算分析分析轉(zhuǎn)子運(yùn)動(dòng)特性兩部分組成。在理論分析的部分,主要分析了平衡轉(zhuǎn)子系統(tǒng)在密封力單獨(dú)作用下的穩(wěn)定性以及葉頂間隙氣流激振力及其影響因素的關(guān)系。分析認(rèn)為,在密封力的單獨(dú)作用下,存在使轉(zhuǎn)子發(fā)生Hopf分岔的臨界轉(zhuǎn)速。而葉頂間隙氣流激振力的大小則隨出氣角度和葉頂間隙的而減小,隨進(jìn)氣速度、進(jìn)氣角度以及氣流密度的增大而增大。在數(shù)值計(jì)算的部分,分別計(jì)算了轉(zhuǎn)子系統(tǒng)無質(zhì)量偏心和有質(zhì)量偏心時(shí)的轉(zhuǎn)子動(dòng)力學(xué)微分方程。其中,對平衡轉(zhuǎn)子的計(jì)算結(jié)果驗(yàn)證了理論分析中轉(zhuǎn)子會(huì)發(fā)生Hopf分岔的結(jié)論。對不平衡轉(zhuǎn)子的計(jì)算結(jié)果顯示,在二者的共同作用下,隨轉(zhuǎn)速的增大轉(zhuǎn)子從單周期運(yùn)動(dòng)經(jīng)過倍周期或者概周期運(yùn)動(dòng)最終變化到混沌狀態(tài)。并且結(jié)果顯示,在轉(zhuǎn)速較小時(shí)葉頂間隙氣流力對轉(zhuǎn)子的作用較大,但隨著轉(zhuǎn)速的不斷增大,其對轉(zhuǎn)子的影響逐漸變?nèi)?相反,密封力對轉(zhuǎn)子的影響隨著轉(zhuǎn)速的增大而增大。
[Abstract]:With the rapid development of national economy, the demand for electricity consumption is also increasing. However, as the main generating unit, the storage of non-renewable resources, such as coal, is decreasing day by day. Therefore, the research, production and development of energy-saving large steam turbine composition is the inevitable trend of thermal power generation. However, with the continuous improvement of steam turbine parameters, the generated airflow excitation force will also increase, and will continue to have a serious trend of development, and ultimately affect the safe operation of steam turbines. Therefore, it is more and more important to study the motion characteristics of rotor under the action of airflow force. In this paper, two main kinds of airflow force, seal force and airflow force of tip clearance caused by eccentricity of impeller are introduced. The model of two kinds of airflow force and the model of rotor are established respectively. Then, the rotor dynamic equations under two kinds of airflow forces are numerically calculated with Matlab as the main calculation tool. This paper mainly consists of two parts: theoretical analysis of rotor stability and numerical analysis of rotor motion characteristics. In the part of theoretical analysis, the stability of the balanced rotor system under the action of sealing force alone and the relationship between the airflow excitation force of the blade tip clearance and its influencing factors are mainly analyzed. It is considered that there is a critical speed of Hopf bifurcation in the rotor under the action of sealing force alone. However, the magnitude of the airflow excitation force of the tip clearance decreases with the outlet angle and the blade tip gap, and increases with the increase of the inlet velocity, the inlet angle and the air density. In the part of numerical calculation, the differential equations of rotor dynamics with mass eccentricity and mass eccentricity are calculated respectively. The calculation results of the balanced rotor verify the conclusion that Hopf bifurcation will occur in the theoretical analysis. The results of the calculation of the unbalanced rotor show that the rotor changes to chaos state with the increase of the speed of the rotor from the one-cycle motion to the periodic motion or the almost periodic motion. The results show that when the rotor speed is small, the effect of airflow force on rotor is great, but with the increase of rotor speed, the effect of seal force on rotor becomes weaker, and the effect of seal force on rotor increases with the increase of rotor speed.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2011
【分類號(hào)】：TK261;TH113

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本文編號(hào)：2080554