發(fā)布時間：2018-03-17 06:22

  本文選題：透平膨脹機　切入點：軸向力　出處：《蘭州理工大學》2014年碩士論文　論文類型：學位論文

【摘要】：透平膨脹機是利用氣體的絕熱等熵膨脹流動來獲得低溫和進行能量回收的主要設(shè)備。是低溫環(huán)境模擬、空氣分離、天然氣液化、氫、氦液化等裝置中的關(guān)鍵部件,是保證裝置穩(wěn)定運行的心臟設(shè)備。隨著工業(yè)經(jīng)濟的高速發(fā)展,對透平膨脹機提出了高速化、大型化的要求。導(dǎo)致透平膨脹機因軸向力過大出現(xiàn)葉輪軸向竄動等故障。因此,通過研究透平膨脹機軸向力,提高軸向力計算精度和軸系運轉(zhuǎn)的穩(wěn)定性以及機組可靠性,對透平膨脹機理論設(shè)計、工程應(yīng)用以及延長設(shè)備使用壽命都具有重要意義。 本文應(yīng)用計算流體動力學軟件FLUNET,以某一透平膨脹機轉(zhuǎn)子系統(tǒng)為研究對象對其軸向力進行了研究和數(shù)值模擬。 分析了透平膨脹機軸向推力,建立了力學分析模型和葉輪間隙及迷密封的整體三維模型。采用FLUNET軟件中的低Re數(shù)k-ε模型和SIMPLEC算法,考慮泄漏、氣體的可壓縮性和粘性的影響,對透平膨脹機軸向推力進行了模擬計算。數(shù)值模擬了由于機械磨損導(dǎo)致密封間隙增大情況下軸向力和間隙泄漏量的變化趨勢,數(shù)值計算結(jié)果顯示隨著密封齒與轉(zhuǎn)子的間隙增大,葉輪間隙側(cè)軸向力逐步減小,間隙的泄漏量隨著間隙的增大而增大。驗證了網(wǎng)格的無關(guān)性,并將數(shù)值模擬結(jié)果與理論公式計算結(jié)果進行了分析比較,找出了造成兩者之間差異的原因。 分析了葉輪間隙側(cè)不同密封腔時透平膨脹機軸向推力的變化,求解出葉輪側(cè)的壓力分布、速度沿軸向分布和間隙泄漏量大小,對不同密封腔時葉輪間隙側(cè)軸向力的大小進行了比較分析。 研究了在直齒密封時透平膨脹機軸向力的變化,并對比分析了直齒密封和斜齒密封時葉輪間隙側(cè)泄漏量和軸向力。分析了造成差異的原因,為透平膨脹機提高機組效率和增加機組穩(wěn)定性提供了方向。
[Abstract]:Turbine expander is the main equipment for obtaining low temperature and energy recovery by using adiabatic isentropic expansion flow of gas. It is a key component in low temperature environment simulation, air separation, natural gas liquefaction, hydrogen, helium liquefaction and so on. With the rapid development of industrial economy, the requirements of high speed and large scale turbine expander are put forward, which lead to the axial movement of impeller due to the excessive axial force of turbine expander and so on. Through the study of axial force of turbine expander, it is of great significance to improve the accuracy of axial force calculation, the stability of shafting operation and the reliability of unit. It is of great significance for the theoretical design, engineering application and prolongation of service life of turbine expander. In this paper, the axial force of a turbine expander rotor system is studied and numerically simulated by the computational fluid dynamics software FLUNET. The axial thrust of turbine expander is analyzed, and the mechanical analysis model and the integral 3D model of impeller clearance and impeller seal are established. The low re number k- 蔚 model and SIMPLEC algorithm in FLUNET software are used to consider the effects of leakage, compressibility and viscosity of gas. The axial thrust of turbine expander is simulated. The variation trend of axial force and clearance leakage is simulated when the seal clearance increases due to mechanical wear. The numerical results show that the axial force and clearance leakage increase with the increase of the gap between the seal teeth and the rotor. The axial force of the impeller clearance decreases gradually, and the leakage of the clearance increases with the increase of the clearance. The irrelevance of the mesh is verified, and the numerical simulation results are compared with the calculated results of the theoretical formula. The reasons for the difference between the two are found. The variation of axial thrust of turbine expander with different seal cavities on the clearance side of impeller is analyzed, and the pressure distribution, velocity distribution along axial direction and clearance leakage amount of impeller side are calculated. The axial force of impeller clearance under different seal cavities is compared and analyzed. The change of axial force of turbine expander during straight tooth seal is studied, and the leakage amount and axial force of impeller clearance in straight tooth seal and oblique tooth seal are compared and analyzed, and the cause of the difference is analyzed. It provides a direction for the turbine expander to improve the efficiency of the unit and increase the stability of the unit.
【學位授予單位】：蘭州理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TB653

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