本文選題：機械密封 + 動壓效應(yīng)�。� 參考：《浙江工業(yè)大學(xué)》2014年博士論文

【摘要】：以微孔為代表的表面織構(gòu)技術(shù)在機械密封端面中得到廣泛應(yīng)用,然而其在高壓和大膜厚條件下產(chǎn)生的動壓效應(yīng)較低,不能有效改善該工況下的密封性能,從而限制了其進(jìn)一步的應(yīng)用。針對此,提出了一類大孔徑流體動壓型表面織構(gòu),使?jié)櫥耗ぎa(chǎn)生匯聚和導(dǎo)向,以期顯著提高其動壓效應(yīng)和液膜的穩(wěn)定性。 論文以大孔徑流體動壓型機械密封為研究對象,考慮液膜的空化現(xiàn)象,建立其理論模型,研究了密封操作參數(shù)與孔型尺寸對密封性能的影響情況,揭示大孔型表面織構(gòu)的作用機理,對其孔型結(jié)構(gòu)進(jìn)行優(yōu)化分析。考慮到密封介質(zhì)壓力對密封變形的影響和液膜壓力與端面變形間的耦合作用,建立了大孔型機械密封的流固力耦合模型,結(jié)合有限單元法與有限差分法求解物理模型,研究了操作參數(shù)和結(jié)構(gòu)參數(shù)對密封環(huán)變形和密封性能的影響情況。搭建了密封性能試驗臺架,進(jìn)行了不同排布的大孔型表面織構(gòu)的摩擦磨損試驗和相應(yīng)機械密封的密封性能試驗。 研究結(jié)果顯示：(1)相較于微孔端面機械密封,大孔徑端面密封在低速下更易產(chǎn)生空化效應(yīng),具有更強的動壓開啟特性；在較大的壓力范圍內(nèi)變化,孔徑或半軸長越長,端面間的液膜穩(wěn)定性越好；(2)大菱形孔具有比其它型孔更好的液膜穩(wěn)定性、開啟特性及較小的泄漏率,在低速時雙向傾斜大菱形孔端面密封可快速打開,可有效減少啟動時的摩擦磨損和泄漏率,非傾斜大菱形孔的液膜穩(wěn)定性是最好的；(3)密封端面的周向波度變形是由端面的孔型結(jié)構(gòu)和轉(zhuǎn)速所決定的,而端面的徑向錐度變形是由密封環(huán)的宏觀結(jié)構(gòu)和內(nèi)外壓力差所決定,且兩類參數(shù)對端面變形的作用是互不影響的；(4)試驗顯示：雙向雙列傾斜菱形孔、ζ=0.6～0.9和越大的孔徑端面密封,可獲得最低的摩擦系數(shù)、溫升和磨損量,同時也驗證了大孔徑端面具有較好的動壓效應(yīng)和耐磨性能。 論文成果完善了大孔徑端面密封的設(shè)計理論與方法,解決了轉(zhuǎn)速較低設(shè)備中微孔端面密封動壓效應(yīng)弱與較大壓力范圍內(nèi)液膜穩(wěn)定性差的問題,具有很強的實用價值。
[Abstract]:The surface texture technology, represented by micropores, is widely used in the mechanical seal face, but the dynamic pressure effect is low under the condition of high pressure and large film thickness, so it can not effectively improve the sealing performance under the condition of high pressure and large film thickness. This limits its further application. In order to improve the dynamic pressure effect and the stability of liquid film, a kind of surface texture with large pore diameter hydrodynamic pressure is proposed, which leads to the convergence and orientation of the lubricating liquid film. In this paper, the large aperture hydrodynamic pressure mechanical seal is taken as the research object. Considering the cavitation phenomenon of liquid film, the theoretical model is established, and the influence of sealing operation parameters and pass size on the seal performance is studied. The action mechanism of surface texture of macroporous surface was revealed and the pore structure was optimized and analyzed. Considering the effect of sealing medium pressure on seal deformation and the coupling effect between liquid film pressure and end surface deformation, a fluid solid coupling model of large pass mechanical seal is established, and the physical model is solved by combining finite element method and finite difference method. The effects of operation parameters and structural parameters on the deformation and sealing performance of seal ring were studied. A test bench for sealing performance was set up, friction and wear tests of large pass surface texture with different arrangement and sealing performance tests of corresponding mechanical seals were carried out. The results show that, compared with the mechanical seal with micropore end face, the large aperture end face seal is easier to produce cavitation effect at low speed, and has stronger dynamic pressure opening characteristics, and the longer the aperture or half shaft length is, the longer the aperture or half shaft length is when the pressure range is large. The better the stability of the liquid film between the end faces is, the better the liquid film stability, the opening characteristic and the smaller leakage rate of the big diamond hole are compared with the other holes. The seal of the bidirectional inclined big diamond hole can be quickly opened at low speed. It can effectively reduce the friction, wear and leakage rate during start-up. The liquid film stability of the non-inclined big diamond hole is the best. (3) the circumferential waviness deformation of the end face of the seal is determined by the pass structure and the rotational speed of the end face. However, the radial taper deformation of the end face is determined by the macro structure of the seal ring and the difference between the internal and external pressure, and the effect of the two kinds of parameters on the end face deformation is independent of each other. The test shows that the bidirectional double-row inclined rhombic hole, the Zeta _ 0. 6 ~ 0. 9 and the larger the aperture end face seal, The lowest friction coefficient, temperature rise and wear rate can be obtained. At the same time, it is proved that the large aperture end face has better dynamic pressure effect and wear resistance. In this paper, the design theory and method of large aperture end face seal are perfected, and the problem of weak dynamic pressure effect and poor stability of liquid film in large pressure range is solved in low rotating speed equipment, which is of great practical value.
【學(xué)位授予單位】：浙江工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TH136

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