2004年--外文翻譯--壓縮機閥設計中靈活性和可靠性的考慮

1、<p>　　中文2350字,1380漢字，7630英文字符</p><p>　　出處：Kwon Y K, Lee G H, Lee T J. The Design of Compressor Valve to Consider the Flexibility and Reliability[J]. 2004.</p><p>　　壓縮機閥設計中靈活性和可靠性的考慮</p&g

2、t;<p>　　權尹基1 李健何2 李太進3</p><p>　　1韓國安山市京畿道東陽技術學院CAD/CAM系</p><p>　　(+82-31-670-7205,+82-670-7209,ykkwon@doowon.ac.kr)</p><p>　　2韓國安山市京畿道東陽技術學院制冷與空調系</p><p>　　(+82-

3、31-670-7153, +82-670-7159, ghlee@doowon.ac.kr)</p><p>　　3韓國安山市京畿道東陽技術學院壓縮機研究實驗室</p><p>　　(+82-31-670-7058,+82-670-7058, leetjin@incheon.ac.kr)</p><p><b>　　摘要</b></p&g

4、t;<p>　　本文定性地介紹了一種從靈活性和可靠性方面考慮壓縮機氣閥設計和開發(fā)的方法。靈活性關系到壓縮機的效率，它和可靠性是壓縮機氣閥設計中兩個最重要的因素。在這個研究中，我們設計了考慮這兩個因素的最佳的二氧化碳壓縮機氣閥。為了獲得最佳的氣閥靈活性，我們進行了壓縮機系統(tǒng)模擬。從這個模擬實驗中們，我們可以獲得一些氣閥設計的重要數據，像最優(yōu)的自然頻率和自由高度。每一個參數像彎曲應力、接觸應力和自然頻率都是從分析有限的要素中獲

5、得。此外，我們還研究了疲勞穩(wěn)定性以獲得最佳的氣閥外形尺寸，確保氣閥的可靠性。</p><p><b>　　1.緒言</b></p><p>　　在壓縮機中，吸氣閥和排氣閥是通過一定壓力制冷劑的流動來保持恒定壓差的關鍵部件之一。如果制冷劑進入汽缸的壓力低，它就會被活塞壓縮。如果制冷劑的壓力高，它就會被排氣閥排入排氣腔。</p><p>　　因此，

6、統(tǒng)一地吸排制冷劑是一個關鍵因素，它決定了壓縮機的性能。在吸氣閥和排氣閥的設計中，有幾個設計因素要考慮。但是，兩個最重要的因素是最佳的靈活性和可靠性。當泄漏和制冷劑的逆流被減到最小時，需要最大的吸排氣壓力來保證最佳性能。這就是說，最佳的靈活性是閥門順利開啟和順利關閉的必要條件。象汽車壓縮機在高速行駛下的負載情形，吸氣閥和排氣閥需要在沖擊和彎曲疲勞的情況下保持正常工作。因此，要求設計要有強的可靠性。在這個研究中，幾個重要的設計因素被考慮在設

7、計二氧化碳制冷的吸氣閥和排氣閥中，計劃獲得最優(yōu)的設計方法。不同于R134，二氧化碳制冷壓縮機主要在高壓的條件下運行，所以氣閥應該在苛刻的工況條件下進行徹底的測試。</p><p>　　本研究采用了兩種不同的方法，第一種，氣閥規(guī)律的設計因素通過壓縮機性能模擬獲得。固有頻率和塞子高度決定了搖板式二氧化碳制冷壓縮機能否獲得最佳性能。</p><p>　　第二，根據性能模擬結果，進行有限要素的分析

8、來確保氣閥的可靠性。經過幾次反復，設計因素最后被確定。 </p><p><b>　　2.性能模擬</b></p><p>　　確定了最佳的閥塞高度和自然頻率，下面的模擬就會被執(zhí)行。壓縮機由六個汽缸和三個控制卷組成。每一個吸氣閥和排氣閥都可以用20個一階微分方程和6個關于質量和溫度的二階動力學方程表示。要同時求解20個一階微分方程和二階動力學方程，先把12個二階微分方

9、程轉化成24個一階微分方程，然后再用龍格-庫塔法解這44個普通的微分方程。</p><p><b>　　3.有限元方法</b></p><p>　　有限元分析可以演示氣閥在運行情況下可靠性的測試。圖1顯示了壓縮機閥的運動。</p><p>　　圖1.壓縮機氣閥運動(1)</p><p>　　如圖1所示，氣閥裝置十分復雜，

10、它在開啟和關閉時伴隨有各種各樣的現象。</p><p>　　本研究中，在安全方面的兩個最嚴重情況下分析閥的結構。利用I-DEAS分析程序和三維殼元件，厚度確定為0.305mm和0.381mm，這兩種都可以從市場上買到。進而獲得閥的彎曲應力，接觸應力和自然頻率。</p><p><b>　　表1.力學性能</b></p><p>　　圖2. 山特

11、維克特20C的微觀結構</p><p>　　我們選擇山特維克特20C來進行分析，其性能列于表1?？瓷厦娴奈⒂^結構圖(圖2)，就會發(fā)現它的主要結構是針型馬氏體。吸氣閥和排氣閥的形狀如圖2.</p><p>　　3.1測定自然頻率和塞子高度</p><p>　　閥的固有頻率越低，壓縮機的性能越高。但如果固有頻率太低，結構的安全性則不能保證。因此，確定最佳的固有頻率非常重

12、要。由于塞子高度和壓縮機的性能也密切相關，它的最佳長度由性能模擬確定。短的塞子有利于可靠性，但相反其會影響壓縮機獲得更好的性能。因此，最佳的固有頻率和塞子高度應該在考慮壓縮機性能后確定。再本研究中，兩個關鍵因素要使壓縮機在1800rpm的時候有70%的容積效率，像R134一樣。表2顯示了一定固有頻率和塞子高度下性能模擬的結果。</p><p><b>　　表2.閥的設計因素</b></

13、p><p>　　圖3. 閥的基本形狀</p><p>　　為了獲得最佳的自然頻率，模擬幾個不同的設計因素(如圖3)，大部分情況下吸氣閥和排氣閥可取各種各樣的寬帶，但是，如果寬度變化太大導致降低可靠性，可以改變閥頭部分的質量來獲取最佳自然頻率。模擬后閥的最終外形如圖4所示。</p><p>　　(a) 吸氣閥 (b)排氣閥<

14、;/p><p>　　圖4. 固有頻率和閥外形</p><p><b>　　3.2彎曲應力</b></p><p>　　當吸氣閥和排氣閥全開時，其位移最大。彎曲應力也應該在這種情況下計算出。雖然接觸應力和疲勞應力在閥設計中更重要，但彎曲應力也是一個重要的設計因素。以吸氣閥來分析，約束條件適用于閥片和墊片之間的區(qū)域。吸氣閥全開，即吸氣腔和汽缸之間的壓差

15、達到最大值。經過性能模擬后，最大壓差確定為0.7MPa。排氣閥的裝載條件是閥全開，閥端接觸到擋板。吸氣閥的彎曲應力分布如圖5所示。</p><p>　　圖5. 吸氣閥的彎曲應力 圖6. 排氣閥的彎曲應力</p><p>　　吸氣閥的最大彎曲應力為/mm，并且應力主要分布在閥的根部。這略微高于材料的疲勞強度(/mm)。但應力通常在罰開啟時變的較高，而當制冷劑從吸入消聲器

16、進入汽缸時，應力又會降低?？紤]到這個事實，我們可以認為，吸氣閥結構上是安全的。排氣閥的彎曲應力分布如圖6所示。它的最大彎曲應力為/mm，它小于材料的疲勞強度。</p><p><b>　　3.3沖擊疲勞</b></p><p>　　大多數報告的閥斷裂的案例，特別是在高壓條件下工作的排氣閥，都是由于沖擊疲勞造成的。從結構的角度看，彎曲疲勞斷裂是吸氣閥的關鍵，沖擊疲勞斷裂

17、是排氣閥的關鍵。在本研究中，閥在開啟和關閉時的速度由性能分析在5000rpm的條件下計算出來。表3和圖7顯示了出閥的速度。</p><p>　　表3. 在5000rpm時的閥速度</p><p><b>　　曲軸轉角(deg)</b></p><p>　　圖7. 5000rpm時的閥速度</p><p>　　考慮沖擊疲勞

18、對可靠性的影響，把以上分析和材料的數據進行比較。山特維克特20C的沖擊疲勞如圖8所列。</p><p><b>　　圖8. 沖擊疲勞</b></p><p>　　盡管在5000rpm條件下的分析結果(5.58m/sec)比材料的數據低，但我們需要考慮用具有更高沖擊疲勞值的新材料代替，以確保在更高運行條件下沖擊疲勞的可靠性。</p><p>&l

19、t;b>　　4.結論</b></p><p>　　有限元分析用來確定二氧化碳壓縮機吸氣閥和排氣閥的最佳設計方法。首先，容積效率的優(yōu)化由性能模擬確定。然后，外形的設計通過幾次有限元分析獲得。最后，最佳的設計外形和確保靈活性和可靠性的固有頻率和應力分布也被確定。但時，需要考慮新材料以確保在更高運行條件下沖擊疲勞的可靠性。</p><p><b>　　參考文獻<

20、/b></p><p>　　山特維克特材料手冊，2004。</p><p>　　The Design of Compressor Valve to</p><p>　　Consider the Flexibility and Reliability</p><p>　　YUN KI KWON1, GEON HO LEE2, TAE JI

21、N LEE3 </p><p>　　1Department of CAD/CAM, Doowon Technical College, Ansung-shi, Kyonggi-do, South Korea (+82-31-670-7205, +82 -670-7209, ykkwon@doowon.ac.kr) </p><p>　　2Department of Refrigeratio

22、n and Air Conditioning, Doowon Technical College, Ansung-shi, Kyonggi-do, South Korea (+82-31-670-7153, +82 -670-7159, ghlee@doowon.ac.kr) </p><p>　　3Compressor Research Lab., Doowon Technical College, Ansun

23、g-shi, Kyonggi-do, South Korea (+82-31-670-7058, +82 -670-7058, leetjin@incheon.ac.kr) </p><p><b>　　ABSTRACT </b></p><p>　　This paper presents a qualitative introduction to the compr

24、essor valve design and development efforts by considered flexibility and reliability. Flexibility that is related to compressor efficiency and structural reliability are two main important factors in compressor valve des

25、ign. In this study, we have designed the optimal COcompressor valve considered these factors. To obtain optimal valve flexibility we performed to system simulation of compressor. From this simulation, we could get some i

26、m</p><p>　　1. INTRODUCTION</p><p>　　In compressor, suction and discharge valve are one of the key components which maintain constant pressure by enabling the move of refrigerant at a certain pre

27、ssure. As the refrigerant enters to cylinder at low pressure, it is compressed by piston. As pressure gets higher, it is send to discharge room by discharge valve.</p><p>　　Therefore, consistent suction and

28、discharge of refrigerant is the key factor, which determines the performance of compressor. There are several design factors to consider in suction and discharge valve design. But, two most significant factors are optima

29、l reliability and flexibility. While the leakage or backflow of refrigerant is minimized, the maximum suction and discharge is necessary to guarantee optimum performance. That is, optimal flexibility is the necessary con

30、dition for smooth opening </p><p>　　Among two different methodology tried in this study, first, design factor of valve system is obtained by performance simulation of compressor. Natural frequency and stoppe

31、r height are determined to maximize the performance of swash plate type CO2 refrigerant compressor.</p><p>　　Secondary, based upon the results of performance simulation, finite element analysis is conducted

32、to ensure the reliability of valve. After several iterations, design factors are finally determined.</p><p>　　2. PERFORMANACE SIMULATION</p><p>　　To determine the optimal height of valve stopper

33、 and natural frequency, the following simulation is performed. The compressor consists of six cylinders and three control volumes. Each could be represented as twenty 1 order differential equations with respect to mass a

34、nd temperature and six 2 order kinetic equations for suction and discharge valve. To solve twenty 1st order differential equations and 2nd order kinetic equations simultaneously,twelve 2nd order differential equations ar

35、e transforme</p><p>　　3. FINITE ELEMENT METHOD</p><p>　　The finite element analysis is performed to test the reliability of valve under loading. The figure 1 shows the valve movement of compress

36、or.</p><p>　　Figure1: The valve movement of compressor (1)</p><p>　　As shown in figure 1, valve mechanism is quite complex, which could accompany various phenomena in opening and closing. For tw

37、o most severe cases in terms of the safety, valve structure is analyzed in this study. I-DEAS analysis program is utilized, and 3D shell element is used. The thickness is set to 0.305mm and 0.381mm, as these two are only

38、 available in the market. The bending stress, contact stress, and natural frequency of valve is obtained as a result.</p><p>　　Table1.Mechanical Properties(1)</p><p>　　Figure 2: Microstructure o

39、f Sandvik 20C</p><p>　　Sandvik 20C is selected for this analysis, and its properties are listed in Table 1. Looking upon microstructure image (figure 2), it is found that the main structure is needle type ma

40、rtensite. The shape of suction and discharge is shown in figure 2.</p><p>　　3.1Determination of natural frequency and stopper height</p><p>　　The lower the natural frequency of valve is, the hi

41、gher the performance of compressor is. But, if the natural frequency is too low, the safety of structure is in danger. Therefore, the determination of optimal natural frequency is very important. Since stopper height is

42、also closely related to the compressor performance, its optimal length is determined by performance simulation. The short stopper is better in terms of reliability, but the opposite is preferred for the better performanc

43、e of comp</p><p>　　Table 2 Design Factor of Valves</p><p>　　Figure 3: Basic shape of Valve</p><p>　　To obtain optimal natural frequency, several different design cases (figure 3) ar

44、e simulated. Mostly the width of suction and discharge valve is varied. But, if the width variation is too big to lower the reliability, the area of valve head is changed to vary its mass for optimal natural frequency. T

45、he final shape of valve after simulation is shown in figure 4.</p><p>　　(a) Suction (1054) (b) Discharge(1384)</p><p>　　Figure 4: Natural frequency and Valve shape</p><p

46、>　　3.2 Bending stress</p><p>　　When suction and discharge valve reach to stopper, its displacement is maximum. The bending stress is also calculated under this condition. Though contact and fatigue stress

47、 is more significant in value design, bending stress is also important design factor. For suction valve analysis, constraint condition is applied to contact area between valve plate and gasket. The loading is set for max

48、imum displacement, where the pressure difference between suction chamber and cylinder is maximum value. Aft</p><p>　　Figure 5: Bending stress of suction valve </p><p>　　Figure 6: Bending stress

49、of discharge valve</p><p>　　Maximum bending stress for suction valve resulted at 50kg /mm, and stress is mainly distributed around valve root. It is slightly higher than the fatigue strength of material (65k

50、g /mm). But, stress is usually higher right after valve opening and gets lowered as refrigerant enters from suction muffler to cylinder. Taking account this fact, we could conclude that suction valve is structurally safe

51、. The bending stress distribution of suction valve is shown in figure 6. Its maximum bending stress i</p><p>　　3.3 Impact Fatigue</p><p>　　Most of reported cases for valve fracture, especially f

52、or discharge valve under high pressure, are due to impact fatigue. From the structural point of view, bending fatigue fracture is critical for the suction valve, and impact fatigue fracture is critical for the discharge

53、valve. In this study, valve velocity at opening and closing is calculated by performance analysis at 5000rpm condition. Table 3 and figure 7 show the valve velocity results.</p><p>　　Table 3 .Valve velocity

54、at 5000 rpm</p><p>　　To consider impact fatigue reliability, the above analysis result is compared with the material data. The impact fatigue of Sandvik 20C is listed in figure 8.</p><p>　　Figur

55、e 8. Impact Fatigue</p><p>　　Though the analysis result (5.58 m/sec) at 5000rpm condition is lower than the material data (8 m/sec), we need to consider changing with new material with higher impact fatigue

56、value to ensure impact fatigue reliability at higher driving condition.</p><p>　　4. CONCLUSION</p><p>　　The finite element analysis is performed to determine the optimal design for suction and d

57、ischarge valve of COcompressor. At first, the optimal design target for volume efficiency is set by performance simulation. Then, design shape which converges to design target is obtained by several iterations of finite

58、element analysis. As a result, optimal design shape with natural frequency and stress distribution, which ensures flexibility and reliability, is determined. But, new material needs to be co</p><p><b>