Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Comparison of the Friction-Loss Coefficient for the Gap of Two Contact Surfaces and a Crack

접촉한 두 평면과 균열한 틈새에서의 유동마찰계수 비교

  • Received : 2011.04.13
  • Accepted : 2011.07.21
  • Published : 2011.10.01
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Abstract

A leak-detection method has been developed by measuring the pressure variation between the inner and outer heattransfer tubes of a double-wall tube steam generator. An experiment was carried out to measure the leak rate in the gap between two surfaces pressed with a hydraulic press in order to simulate the phenomena, and a correlation was determined for the leak rate in a micro gap. However, in the correlation, the gap width and friction coefficient were coupled with the surface roughness, which affects the two parameters. The two parameters were separated using a surface-contact model to develop a correlation for the friction coefficient. The correlation was compared with the existing correlations used for crack analysis. Although the applied ranges of Reynolds numbers were different, the developed correlation for Reynolds numbers of 0.1.0.35 showed similar tendencies to existing correlations used for higher Reynolds numbers.

이중벽관 증기발생기에서 전열관의 내관과 외관 사이의 틈새에 채워진 헬륨가스의 압력변동으로 전열관의 파손을 감지하는 방법이 개발되고 있다. 이 현상을 모사하기 위해 압력으로 밀착된 두 평판사이의 미세한 틈새에서의 누설률을 측정하여 실험식을 개발하였다. 이 실험식에서는 틈새의 간격과 유동마찰계수가 표면조도에 의해 상호 결합된 형태로 기술되는데, 간단한 평판접촉 모델을 사용하여 유동마찰계수 식을 분리하였다. 이 실험식과 균열에서의 누설률 예측에 사용되고 있는 기존의 유동마찰계수 관련 실험식들을 상호 비교하였다. 레이놀즈 수의 적용범위가 상이함에도 불구하고 개발한 실험식이 0.1~0.35 에서는 레이놀즈 수가 높은 경우에 적용되는 실험식들과 유사한 값을 보였다.

Keywords

References

  1. Nam, H., Choi, B. and Kim, J., 2010, "On the Design Concept Technology Development of a Double Wall Tube Steam Generator," Trans. of the KSME (A), 34(9), 1217-1225. https://doi.org/10.3795/KSME-A.2010.34.9.1217
  2. Grine, L. and Bouzid, A., 2009, "Correlation of Gaseous Mass Leak Rates Through Micro and Nano-Porous Gaskets," Proc. of ASME: Pressure Vessel and Piping Conf., Prague, Czech.
  3. Cazauran, X, Birembaut, Y. and Hahn, R., Kockelmann, H., Moritz, S., 2009, "Gas Leakage Correlation," Proc. of ASME: Pressure Vessel and Piping Conf., Prague, Czech.
  4. Rahman, S., Ghadiali, N., Wilkowski, G.M. and Paul, D.A., 1997, "Computer Model for Probabilistic Leak-Rate Analysis of Nuclear Piping and Piping Welds," Int. J. of Pressure Vessels and Piping, 70, 209-221. https://doi.org/10.1016/S0308-0161(96)00032-4
  5. Rudland, D.L., Wilkowski, G. and Scott, P., 2002, "Effects of Crack Morphology on Leak-Rate Calculations in LBB Evaluations," Int. J. of Pressure Vessels and Piping, 79, 99-102. https://doi.org/10.1016/S0308-0161(01)00138-7
  6. Beck, S.B.M., Bagshaw, N.M. and Yates, J.R., 2005, "Explicit Equations for Leak Rates Through Narrow Crack," Int. J. of Pressure Vessels and Piping, 82, 565-570. https://doi.org/10.1016/j.ijpvp.2004.12.005
  7. Majumdar, S., Kasza, K., Bakhtiari, S., Park, J.Y., Oras, J., Franklin, J., Yulak, C. and Shack, W.J., 2009, "Stambaugh M. Steam Generator Tube Integrity Issues: Pressurization Rate Effects, Failure Maps, Leak Rate Correlation Models, and Leak Rates in Restricted Areas," NUREG/CR-6879, U.S. NRC.
  8. Chang, Y.S., Jeong, J.U., Kim, Y.J., Hwang, S.S. and Kim, H.P., 2010, "Enhancement of Leak Rate Estimation Model for Corroded Cracked Thin Tubes," Int. J. of Pressure Vessels and Piping, 87, 52-57. https://doi.org/10.1016/j.ijpvp.2009.11.004
  9. Li, X., Shi, S., Zhang, Z. and Li, X., 2010, "Leak Rate Calculation for LBB Analysis in High Temperature Gascooled Reactors," Nuclear Engineering Design, 240, 3231-3237. https://doi.org/10.1016/j.nucengdes.2010.06.003
  10. Narabayashi, K., Fujii, M., Matsumoto, K. and Horimizu, Y., 1991, "Experimental Study on Leak Flow Model Through Fatigue Crack in Pipe," Nuclear Engineering Design, 28, 17-27.
  11. Nam, H., Kim, J., Choi, B., Kim, J. and Lee, Y., 2010, "Experimental Investigation of the Leak Detection Capability for a Double Tube," KAERI/TR-4160/2010.
  12. Idelchik, I.E., 1986, "Handbook of Hydraulic Resistance," Hemisphere Publishing Co., New York, 57-112.