渦輪轉子-軸承系統模態分析與驗證

本文使用有限元素方法，針對60瓩級外軸式渦輪引擎，建立轉子-軸承系統之離散模型，根據結構各部份組裝之實際狀況，將整機渦輪轉子-軸承系統劃分成若干個可分離之子結構系統，包括葉輪、轉軸、導流板、渦輪及軸承，再以各子結構連接面上節點的動態參數一致性及力平衡，整合渦輪轉子系統的運動方程式。以有限元素分析商用軟體ANSYS，探討重要零組件及渦輪機系統之模態特性，並以實驗驗證之。為了驗證建模以及比較分析結果的準確性，本文結合模態實驗和有限元素的混合建模方法，經由實驗與分析求得之模態振形及自然頻率相互比較，以實驗值為基準，並根據有限元素模型的物理意義，修正各子結構之動態特性，以及調整連接面的動態參數，使分析結果與實驗結果相比得到很高的正確性，除了可驗証分析模型之準確性，亦可鑑別子結構連接面間接點之動態參數，以提高分析精確度，建立一個成功且可靠的渦輪轉子-軸承系統。

關鍵字

60瓩級外軸式渦輪引擎；轉子-軸承系統；模態測試；模態分析；有限元素法

並列摘要

This study builds the discrete model of the rotor-bearing system based on finite element (FE) method for 60kw innovative micro gas turbine, The assembled system is separated into several dividable sub-structures, which including impeller, shaft, guide fan, turbine and bearings. The motion equation of whole structures is combined by the unity of the dynamic variables and force balances on connections of each substructure. Additionally, utilizing commercial software ANSYS to investigate the modal characteristics of the turbine engine systems and its key components, and furthermore verifies the results of analysis via experiments of modal testing. Besides verifying the model and comparing with the results of analysis, this study presents the hybrid method, which combines the experiment of modal testing and FE model. The mode shapes and natural frequencies are obtained by comparing the results of experiment with analysis. Simultaneously, according to the physical signification of FE model, modify the dynamic characteristics of each sub-structure and adjust the dynamic parameters between connected interfaces based on the experimental values to arise the validity by decreasing the errors of analysis and experiment. Not only examining the accuracy of analysis module but also finding out the dynamic parameter of structures, that can increase the analysis accuracy to establish a success and dependable turbine rotor-bearing system.

並列關鍵字

rotor-bearing system ； finite element method ； modal analysis ； 60kw innovative micro gas turbine ； modal testing

參考文獻

[1] Ruhl, R. L. and Booker, J. F., “A Finite Element Model for Distributed Parameter Turborotor Systems,” ASME Journal of Engineering for Industry, Vol. 94, pp. 126-132, 1972.

[2] Nelson, H. D. and McVaugh J. M., “The Dynamics of Rotor-Bearing Systems Using Finite Elements,” ASME Journal of Engineering for Industry, Vol. 98, No. 2, May, pp. 593-600, 1976.

[3] Zorzi, E. S. and Nelson, H. D., “Finite Element Simulation of Rotor-Bearing Systems with Internal Damping,” ASME Journal of Engineering for Power, January, pp. 71-76, 1977.

[4] Nelson, H. D., “A Finite Rotating Shaft Element Using Timoshenko Beam Theory,” ASME Journal of Mechanical Design, Vol. 102, pp. 793-803, 1980.

[6] Özgüven, H. N. and Özkan, Z. L., “Whirl Speeds and Unbalance Response of Multibearing Rotors Using Finite Elements,” ASME Journal of Vibration , Acoustics, Stress, and Reliability in Design, Vol. 106, pp. 72-79, 1984.

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渦輪轉子-軸承系統模態分析與驗證

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