低壓腔渦旋壓縮機止推軸承潤滑特性數(shù)值分析
發(fā)布時間：2018-09-17 09:39
【摘要】：能源危機的日益加劇,以及全球氣候不斷變暖的趨勢正在深刻改變人們的生活方式,人們越來越意識到節(jié)約能源和減少能耗對改善地球生態(tài)環(huán)境的重要性。渦旋壓縮作為一種新型制冷壓縮機,以其高效率、低噪音、運轉穩(wěn)定以及關鍵零部件少等優(yōu)點而受到空調市場上的廣泛關注。自從上世紀80年代渦旋壓縮機首先被應用到商用空調上以來的三十多年間,對渦旋壓縮機性能的研究日益廣泛深入。在渦旋壓縮機中,止推軸承主要是用來平衡氣體介質在壓縮過程中產生的軸向氣體力,由于滑動止推軸承具有良好的軸向承載力和低摩擦特性而在生產實際中被廣泛采用。低壓腔渦旋壓縮機止推軸承是由動渦旋盤背面和支架體上表面構成。動渦旋盤公轉過程中,動渦旋盤受到的切向氣體力、徑向氣體力以及本身由于偏心旋轉運動而產生的離心力并未與動渦旋盤驅動平面共面,由此形成了一個使動渦旋盤發(fā)生傾覆的傾覆力矩。動渦旋盤的傾覆可以使止推軸承產生幾何楔形,楔形的幾何形狀有利于潤滑油膜因動壓效應而產生油膜壓力,動壓油膜的形成可以有效平衡軸向力,因此對止推軸承潤滑性能的理論分析很有必要。本文主要研究動渦旋盤受到傾覆力矩的作用使止推軸承承壓面產生傾斜而引起的止推軸承潤滑特性產生變化問題。首先通過對止推軸承止推合力以及傾覆力矩的分析以及雷諾方程的建立,并利用數(shù)值方法求解了雷諾方程、油膜形成的合力、力矩與止推軸承受到的力、力矩組成的非線性方程組。在一個循環(huán)周期內,分析了止推軸承處油膜壓力以及油膜厚度分布情況,以及中心油膜厚度、動渦旋盤傾斜角和傾斜方位角的變化情況。在此基礎上,研究了主軸轉速對止推軸承潤滑特性的影響,并分析了止推合力在止推軸承徑向的位置變化時對動壓油膜形成的影響。研究結果表明:油膜壓力主要分布在動渦旋盤傾斜收斂區(qū)域,并呈U形形狀分布。主軸旋轉一周,U形動壓油膜隨主軸的變化交替出現(xiàn)在止推軸承不同位置處,這預示著動壓油膜可以在止推軸承上開設的環(huán)形油槽里順暢流動,減少了潤滑油的泄漏,而且最大油膜壓力、中心油膜厚度和動渦旋盤傾斜角隨主軸改變并不明顯。其次,研究表明只有當止推合力處在一定徑向范圍內時,數(shù)值求解過程中才能得到收斂解,而當止推合力超出這一范圍時,動壓油膜有可能不能正常形成,這會造成止推軸承金屬與金屬之間的直接接觸,磨損或者不穩(wěn)定現(xiàn)象的發(fā)生。最后通過對渦旋壓縮機結構參數(shù)進行優(yōu)化設計以此來改善止推軸承的潤滑情況。
[Abstract]:With the worsening of the energy crisis and the trend of global warming, people are becoming more and more aware of the importance of energy conservation and energy consumption in improving the ecological environment of the earth. Vortex compression, as a new type of refrigeration compressor, has attracted wide attention in the air conditioning market because of its high efficiency, low noise, stable operation and few key parts. Since the scroll compressor was first applied to commercial air conditioning in the 1980s, the research on the performance of scroll compressor has been more and more extensive. In scroll compressors, thrust bearings are mainly used to balance the axial gas force produced by gas medium during compression. Sliding thrust bearings are widely used in production because of their good axial bearing capacity and low friction characteristics. The thrust bearing of the low-pressure cavity scroll compressor is composed of the back of the moving scroll disk and the upper surface of the bracket. The tangential gas force, the radial gas force and the centrifugal force caused by the eccentric rotating motion are not coplanar with the driving plane of the moving vortex disk. Thus a capsizing moment is formed to overturn the moving vortex disk. The overturning of the dynamic scroll disk can make the thrust bearing produce geometric wedge. The geometric shape of the wedge is favorable to the oil film pressure caused by the dynamic pressure effect. The formation of the dynamic pressure oil film can effectively balance the axial force. Therefore, it is necessary to analyze the lubrication performance of thrust bearing. In this paper, the lubricating characteristics of thrust bearings caused by the tilting of the bearing due to the overturning moment of the dynamic vortex disk are studied. Firstly, through the analysis of thrust force and overturning moment of thrust bearing and the establishment of Reynolds equation, the resultant force of oil film formation, the force of torque and thrust bearing are solved by numerical method. Nonlinear equations of moment composition. The oil film pressure and oil film thickness distribution at the thrust bearing, the variation of the central oil film thickness, the tilt angle and the tilt azimuth angle of the moving vortex disk are analyzed in a cycle. On this basis, the influence of spindle speed on the lubrication characteristics of thrust bearing is studied, and the influence of thrust force on the formation of hydrodynamic oil film is analyzed when the thrust force changes in the radial position of thrust bearing. The results show that the oil film pressure is mainly distributed in the inclined convergent region of the moving vortex disk, and the oil film pressure is distributed in the shape of U shape. The oil film of U-shaped dynamic pressure appears alternately in different positions of thrust bearing with the change of spindle around the spindle, which indicates that the oil film of dynamic pressure can flow smoothly in the annular oil tank set up on the thrust bearing, thus reducing the leakage of lubricating oil. Moreover, the maximum oil film pressure, the thickness of the central oil film and the tilting angle of the moving vortex disk do not change significantly with the spindle. Secondly, it is shown that only when the thrust force is in a certain radial range, the convergence solution can be obtained in the numerical solution process, but when the thrust force exceeds this range, the dynamic pressure oil film may not be formed normally. This can lead to direct contact, wear or instability between thrust bearing metals and metals. Finally, the lubrication of thrust bearing is improved by optimizing the structure parameters of scroll compressor.
【學位授予單位】：蘭州理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB652
本文編號：2245470
[Abstract]:With the worsening of the energy crisis and the trend of global warming, people are becoming more and more aware of the importance of energy conservation and energy consumption in improving the ecological environment of the earth. Vortex compression, as a new type of refrigeration compressor, has attracted wide attention in the air conditioning market because of its high efficiency, low noise, stable operation and few key parts. Since the scroll compressor was first applied to commercial air conditioning in the 1980s, the research on the performance of scroll compressor has been more and more extensive. In scroll compressors, thrust bearings are mainly used to balance the axial gas force produced by gas medium during compression. Sliding thrust bearings are widely used in production because of their good axial bearing capacity and low friction characteristics. The thrust bearing of the low-pressure cavity scroll compressor is composed of the back of the moving scroll disk and the upper surface of the bracket. The tangential gas force, the radial gas force and the centrifugal force caused by the eccentric rotating motion are not coplanar with the driving plane of the moving vortex disk. Thus a capsizing moment is formed to overturn the moving vortex disk. The overturning of the dynamic scroll disk can make the thrust bearing produce geometric wedge. The geometric shape of the wedge is favorable to the oil film pressure caused by the dynamic pressure effect. The formation of the dynamic pressure oil film can effectively balance the axial force. Therefore, it is necessary to analyze the lubrication performance of thrust bearing. In this paper, the lubricating characteristics of thrust bearings caused by the tilting of the bearing due to the overturning moment of the dynamic vortex disk are studied. Firstly, through the analysis of thrust force and overturning moment of thrust bearing and the establishment of Reynolds equation, the resultant force of oil film formation, the force of torque and thrust bearing are solved by numerical method. Nonlinear equations of moment composition. The oil film pressure and oil film thickness distribution at the thrust bearing, the variation of the central oil film thickness, the tilt angle and the tilt azimuth angle of the moving vortex disk are analyzed in a cycle. On this basis, the influence of spindle speed on the lubrication characteristics of thrust bearing is studied, and the influence of thrust force on the formation of hydrodynamic oil film is analyzed when the thrust force changes in the radial position of thrust bearing. The results show that the oil film pressure is mainly distributed in the inclined convergent region of the moving vortex disk, and the oil film pressure is distributed in the shape of U shape. The oil film of U-shaped dynamic pressure appears alternately in different positions of thrust bearing with the change of spindle around the spindle, which indicates that the oil film of dynamic pressure can flow smoothly in the annular oil tank set up on the thrust bearing, thus reducing the leakage of lubricating oil. Moreover, the maximum oil film pressure, the thickness of the central oil film and the tilting angle of the moving vortex disk do not change significantly with the spindle. Secondly, it is shown that only when the thrust force is in a certain radial range, the convergence solution can be obtained in the numerical solution process, but when the thrust force exceeds this range, the dynamic pressure oil film may not be formed normally. This can lead to direct contact, wear or instability between thrust bearing metals and metals. Finally, the lubrication of thrust bearing is improved by optimizing the structure parameters of scroll compressor.
【學位授予單位】：蘭州理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB652
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