本文選題：油膜振蕩 + 故障診斷　； 參考：《太原理工大學(xué)》2011年碩士論文

【摘要】：滑動(dòng)軸承的油膜渦動(dòng)、油膜振蕩是高速輕載轉(zhuǎn)子運(yùn)轉(zhuǎn)過程中最易出現(xiàn)的一種以油膜力引起的特有故障,油膜振蕩可能導(dǎo)致整個(gè)機(jī)組的毀壞,造成嚴(yán)重的事故和經(jīng)濟(jì)損失。由于影響油膜動(dòng)力特性因素的復(fù)雜性和現(xiàn)有油膜失穩(wěn)理論的局限性以及理論研究和實(shí)際應(yīng)用上的差距使得油膜失穩(wěn)研究和應(yīng)用有待繼續(xù)深入和完善,以采取有效措施來預(yù)防、控制和阻止滑動(dòng)軸承在工作過程中的失穩(wěn)和破壞。 本文一方面以試驗(yàn)研究為基礎(chǔ),對(duì)高速輕載軸承典型性失穩(wěn)案例進(jìn)行了測(cè)定。通過幅頻特性曲線及軸心軌跡圖對(duì)軸承從起動(dòng)到產(chǎn)生油膜振蕩的整個(gè)過程的實(shí)測(cè)分析,總結(jié)了油膜軸承失穩(wěn)狀態(tài)特征變化,從而對(duì)油膜振蕩故障診斷提供了可靠的理論依據(jù)；另一方面,在實(shí)驗(yàn)室軸承模型基礎(chǔ)上借助計(jì)算流體動(dòng)力學(xué)Fluent軟件數(shù)值模擬得到滑動(dòng)軸承三維油膜力場(chǎng)及溫度場(chǎng)分布,對(duì)比分析了轉(zhuǎn)速、軸承間隙比及進(jìn)油壓力等因素對(duì)軸承穩(wěn)定性的影響。同時(shí),利用UDF自定義程序?qū)u動(dòng)復(fù)合運(yùn)動(dòng)進(jìn)行了動(dòng)網(wǎng)格處理,得到失穩(wěn)狀態(tài)下的力場(chǎng)分布特征。 通過對(duì)動(dòng)壓滑動(dòng)軸承油膜穩(wěn)定性的試驗(yàn)研究和數(shù)值模擬,本文得出的主要結(jié)論如下： 1、依據(jù)油膜失穩(wěn)特征,全過程分為四個(gè)區(qū)：亞臨界轉(zhuǎn)速區(qū),臨界轉(zhuǎn)速共振區(qū),超臨界轉(zhuǎn)速平穩(wěn)渦動(dòng)區(qū),油膜振蕩區(qū)。高速輕載轉(zhuǎn)子半頻成分的起始出現(xiàn)在第一區(qū)居多但常很微弱；到第二區(qū)基頻引發(fā)臨界轉(zhuǎn)速強(qiáng)迫共振,半頻影響力減�。坏谌齾^(qū)1X頻與半頻相當(dāng),影響均較弱,振幅較��；接近2倍臨界臨界轉(zhuǎn)速進(jìn)入第四區(qū)半頻幅值劇增,振幅穩(wěn)定,1X頻分及其他諧波影響可忽略；在第二區(qū)臨界轉(zhuǎn)速處相位發(fā)生了180°轉(zhuǎn)變,而在第一區(qū)和第三區(qū),無論渦動(dòng)出現(xiàn)與否,失穩(wěn)與否相位不變。第四區(qū)發(fā)生油膜振蕩后相位極度不穩(wěn)定會(huì)頻繁突變。 2、油膜渦動(dòng)時(shí)軸心軌跡特征：軸心軌跡的形狀是各類頻份的疊加效果,渦動(dòng)時(shí)不規(guī)則軸心軌跡可以分解為幾種頻份的規(guī)則軌跡。某種頻份越大時(shí),軌跡疊加形狀就越單一越規(guī)則,反之越凌亂。提出：對(duì)于油膜振蕩的診斷,可以結(jié)合頻譜圖及軸心軌跡分解效果找到引起不穩(wěn)定滑動(dòng)軸承失穩(wěn)的故障原因。 3、內(nèi)八字軸心軌跡的存在只是局限于臨界轉(zhuǎn)速共振區(qū),也就是作者劃分的第二區(qū),當(dāng)達(dá)到第三區(qū)及其第四區(qū)時(shí),軸心軌跡反而可能呈現(xiàn)大直徑規(guī)則橢圓,不能把內(nèi)八字軌跡作為渦動(dòng)發(fā)生的標(biāo)準(zhǔn)。這對(duì)油膜振蕩特征故障診斷工作提出了新的依據(jù)。 4、通過UDF自定義程序?qū)κХ�(wěn)狀態(tài)下的渦動(dòng)復(fù)合運(yùn)動(dòng)的瞬態(tài)模擬,在油膜力場(chǎng)中不存在一個(gè)固定的最小油膜間距h_(min)平衡點(diǎn),油膜壓力以正壓為主。失穩(wěn)后,流過最小厚膜厚度h_(min)處的油膜量很小,沒有負(fù)壓區(qū),潤滑油在楔形收斂區(qū)不斷的積累下產(chǎn)生了極大的油膜渦動(dòng)推動(dòng)力。 5、通過流體動(dòng)力學(xué)軟件Fluent對(duì)穩(wěn)態(tài)下滑動(dòng)軸承的模擬分析得到了油膜力場(chǎng)和溫度場(chǎng)三維分布特點(diǎn)。隨著轉(zhuǎn)速的增加,最大正負(fù)壓都呈現(xiàn)線性同步增長且位置與轉(zhuǎn)速無關(guān),油膜最高溫度明顯增加且逐漸靠近進(jìn)油口,影響范圍擴(kuò)大；小間隙油膜正負(fù)壓力極值增大,軸頸位置沿旋轉(zhuǎn)正向上移,偏心減小,不利于軸承穩(wěn)定；對(duì)于頂端單孔進(jìn)油軸承,隨壓力增大,正壓增大,而負(fù)壓減小且具有-105Pa左右極限值,最大正壓區(qū)域轉(zhuǎn)移到進(jìn)油口,進(jìn)油壓力越大,越有利于軸承穩(wěn)定。 通過數(shù)值模擬與試驗(yàn)測(cè)定結(jié)果比較,驗(yàn)證了數(shù)值模擬方法在油膜振蕩研究領(lǐng)域的可行性,為進(jìn)一步完善油膜失穩(wěn)理論提供了可靠的理論依據(jù)。
[Abstract]:The oil film oscillation of the sliding bearing is the most common fault caused by the oil film force during the operation of the high speed light load rotor. The oil film oscillation may lead to the destruction of the whole unit and cause serious accident and economic loss. Because of the complexity of the dynamic characteristics of the oil film and the limitation of the existing oil film instability theory The gap between the theoretical research and the practical application makes the research and application of oil film instability need to be further developed and perfected, so as to take effective measures to prevent, control and prevent the instability and damage of the sliding bearing in the working process.
On the one hand, on the one hand, the typical instability case of high speed light load bearing is measured on the basis of experimental research. Through the measurement and analysis of the whole process of the bearing from starting to producing oil film oscillation by the amplitude frequency characteristic curve and the axis locus diagram, the characteristics of the instability state of the oil film bearing are summarized, thus the fault diagnosis of the oil film oscillation is provided. On the other hand, on the basis of the laboratory bearing model, the distribution of the three dimensional oil film force field and temperature field of the sliding bearing is obtained by the numerical simulation of the computational fluid dynamics Fluent software. The influence of the rotational speed, the bearing clearance ratio and the oil inlet pressure on the stability of the bearing is compared and analyzed. At the same time, the UDF custom program is used. The vortex composite motion is processed by dynamic mesh, and the distribution characteristics of the force field in the unstable state are obtained.
Through the experimental study and numerical simulation of the oil film stability of the hydrodynamic sliding bearing, the main conclusions obtained in this paper are as follows:
1, according to the characteristics of oil film instability, the whole process is divided into four regions: subcritical speed zone, critical rotational speed resonance region, supercritical rotational speed stationary vortex area, oil film oscillating region. The beginning of half frequency component of high speed light load rotor appears in the first area most but often very weak; to the second zone, the critical speed of the critical speed is forced to resonate, and the half frequency influence decreases; In the three zone, the 1X frequency is equal to the half frequency, the influence is weak and the amplitude is small; the close 2 times critical critical speed increases sharply in the fourth zone and half frequency amplitude, the amplitude is stable, the 1X frequency and other harmonics can be neglected; the phase of the critical speed at the second zone is 180 degrees, and the phase in the first and third regions, whether or not the vorticity appears or not, is unstable or not. Invariably, phase instability occurs frequently after oil oscillation occurs in the fourth area.
2, the characteristics of the axis trajectory of the oil film whirling: the shape of the axis track is the superposition effect of all kinds of frequency, and the irregular axis trajectory of the vortex can be divided into several regular tracks. When a certain frequency is bigger, the more the shape of the track is more irregular and vice versa. And the effect of axis trajectory decomposition is used to find out the cause of instability of unstable sliding bearing.
3, the existence of the inner eight character axis locus is limited to the critical speed resonance region, which is also the second region of the author's division. When it reaches the third area and the fourth area, the axis locus may present a large diameter regular ellipse, which can not be used as a standard for the occurrence of the vorticity. This is a new method for the fault diagnosis of the oil film oscillation characteristics. The basis for it.
4, through the transient simulation of the vortex complex motion in the unstable state by UDF custom program, there is no fixed minimum oil film spacing h_ (min) equilibrium point in the oil film force field, and the oil film pressure is mainly positive pressure. After the instability, the oil film volume at the minimum thick film thickness h_ (min) is very small, there is no negative pressure zone, and the lubricating oil is constantly in the wedge convergence zone. The accumulation of oil gave rise to the driving force of oil whirling.
5, the three-dimensional distribution characteristics of the oil film force field and the temperature field are obtained by the simulation analysis of the steady state sliding bearing by the fluid dynamic software Fluent. With the increase of the speed, the maximum positive and negative pressure is linearly and synchronously increased and the position is independent of the speed. The maximum temperature of the oil film increases obviously and is close to the inlet of the oil, and the influence range is enlarged. The positive and negative pressure of the gap oil film increases, the position of the shaft neck moves upward along the rotation and the eccentricity decreases, which is not conducive to the stability of the bearing; for the top single hole oil bearing, the positive pressure increases with the pressure increasing, while the negative pressure decreases and has the limit value of about -105Pa, the maximum positive pressure region is transferred to the inlet, the greater the pressure of the oil intake, the more conducive to the stability of the bearing.
By comparing the numerical simulation with the test results, the feasibility of the numerical simulation method in the field of oil film oscillation is verified, which provides a reliable theoretical basis for further improving the theory of oil film instability.

【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2011
【分類號(hào)】：TH133.31

【引證文獻(xiàn)】

相關(guān)期刊論文 前2條

1 黃首峰;郭紅;張紹林;岑少起;;基于FLUENT的徑向滑動(dòng)軸承油膜壓力仿真[J];機(jī)械設(shè)計(jì)與制造;2012年10期

2 胡燦;薛俊;謝斌;;動(dòng)壓滑動(dòng)軸承油膜不同流態(tài)時(shí)的油膜力場(chǎng)研究[J];潤滑與密封;2012年10期

相關(guān)碩士學(xué)位論文 前2條

1 黃首峰;基于FLUENT的機(jī)床主軸動(dòng)壓軸承靜特性研究[D];鄭州大學(xué);2012年

2 林圣強(qiáng);滑動(dòng)軸承油膜厚度對(duì)轉(zhuǎn)子穩(wěn)定性和振動(dòng)的影響[D];東北電力大學(xué);2013年

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本文編號(hào)：1844983