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Shape Optimization of Three-Way Reversing Valve for Cavitation Reduction

3 방향 절환밸브의 공동현상 저감을 위한 형상최적화

  • Received : 2015.03.30
  • Accepted : 2015.08.09
  • Published : 2015.11.01

Abstract

A pair of two-way valves typically is used in automotive washing machines, where the water flow direction is frequently reversed and highly pressurized clean water is sprayed to remove the oil and dirt remaining on machined engine and transmission blocks. Although this valve system has been widely used because of its competitive price, its application is sometimes restricted by surging effects, such as pressure ripples occurring in rapid changes in water flow caused by inaccurate valve control. As an alternative, one three-way reversing valve can replace the valve system because it provides rapid and accurate changes to the water flow direction without any precise control device. However, a cavitation effect occurs because of the complicated bottom plug shape of the valve. In this study, the cavitation index and percent of cavitation (POC) were introduced to numerically evaluate fluid flows via computational fluid dynamics (CFD) analysis. To reduce the cavitation effect generated by the bottom plug, the optimal shape design was carried out through a parametric study, in which a simple computer-aided engineering (CAE) model was applied to avoid time-consuming CFD analysis and difficulties in achieving convergence. The optimal shape design process using full factorial design of experiments (DOEs) and an artificial neural network meta-model yielded the optimal waist and tail length of the bottom plug with a POC value of less than 30%, which meets the requirement of no cavitation occurrence. The optimal waist length, tail length and POC value were found to 6.42 mm, 6.96 mm and 27%, respectively.

자동차부품 세척장비는 엔진과 변속기 블록 등의 가공과정에서 잔류하는 기름때를 제거하며, 잦은 수류방향 전환과 고압수의 분사를 위해 한 쌍의 2 방향 밸브를 사용한다. 그러나 정교한 밸브제어장치 없이 2 방향 밸브를 사용하는 경우 급격한 수류방향 전환에 따른 맥동현상이 발생하여 사용에 어려움이 따른다. 대안으로 하나의 3 방향 절환밸브를 사용하는 방법은 정교한 제어장치 없이도 정확한 수류방향 절환이 원활히 이루어져 이러한 문제점을 해결할 수 있다. 그러나 복잡한 유로 및 바텀플러그 형상으로 인해 유속변화가 심하게 발생하여 공동현상이 나타날 수 있다. 본 연구에서는 3 방향 절환밸브 내의 유동특성을 해석적으로 평가하였으며, 바텀플러그 하부에서 나타나는 공동현상을 공동화지표와 POC(Percent of cavitation)를 도입하여 정량화하였다. 공동현상의 저감을 위해 바텀플러그 형상을 매개변수화하고, 해석의 수렴성 개선과 해석시간을 단축시킬 수 있는 단순 유한요소모델을 이용하여 유동해석을 통한 형상최적설계를 실시하였다. 완전요인배치법을 통한 실험계획법과 인공신경망 기반 반응표면모델을 적용하여 공동현상이 발생하지 않는 POC 가 30% 미만인 바텀플러그의 형상을 제시하였다. 얻어진 최적해는 POC 27%에 대하여 바텀플러그의 허리길이와 꼬리길이가 각각 6.42mm 및 6.96mm 이다.

Keywords

References

  1. Proceco Ltd., Industrial parts washer, http://www.proceco.com/industries/automotive/Aqueous-Parts-Cleaning/Automotive-Aqueous-cleaning -Engine-Components.php.
  2. Brian, N., 2007, Handbook of Valves and Actuators, Roles & Associates Ltd, UK, pp. 82-93.
  3. Franc, J. P. and Michel, J. M., 2003, Fundamentals of Cavitation, Grenoble Sciences, France, pp. 20-82.
  4. ISA-RP75.23, 1995, "Considerations for Evaluating Control Valve Cavitation," the Instrument Society of America.
  5. Lee, J. H., Baek, S. H., Park, J. H., Park, S. I. and Park, Y. C., 2013, "Experimental and Numerical Investigation for Reducing Cavitation of Butterfly Valve with Perforated pate," Trans. Korean Soc. Mech. Eng. B, Vol. 37, No. 9, pp. 176-177.
  6. Jo, S. H., Kim, H. J. and Song, K. W., 2014, "A Numerical Study for Reducing Cavitation in a Butterfly Valve with a Perforated Plate," The KSFM Journal of Fluid Machinery, Vol. 17, No. 3, pp.65-70. https://doi.org/10.5293/kfma.2014.17.3.065
  7. Kubo, M., Araki, T. and Kimura, S., 2003, "Internal flow analysis of nozzles for DI diesel engines using a cavitation model," JSAE Review 24, pp.255-261. https://doi.org/10.1016/S0389-4304(03)00034-1
  8. Kim, D. K. and Sohn, C. H., 2013, "Numerical Study on Cavitation Reduction in Velocity-Control Trim of Valve with High Pressure Drop," Trans. Korean Soc. Mech. Eng. B, Vol. 37, No. 9, pp. 863-871. https://doi.org/10.3795/KSME-B.2013.37.9.863
  9. ANSYS Inc., http://www.ansys.com.
  10. Park, K. H. and Kim, J. G., 2008, "Assessment of Turbulence Models for Engine Intake and Compression Flow Analysis," Journal of the Korean Society of Marine Engineering, Vol. 32, No. 8, pp. 1129-1140. https://doi.org/10.5916/jkosme.2008.32.8.1129
  11. Kim, M. J., Jin, H. B., Son, C. H. and Chung, W. J., 2013, "Numerical Analysis on Cavitation of Centrifugal Pump," KSFM Journal of Fluids Engineering, Vol. 16, No. 2, pp. 27-34.
  12. Owen, A., 1992, "Orthogonal Arrays for Computer Experiments, Integration and Visualization," Statistica Sinica, Vol. 2, pp. 439-452.
  13. SAS Institute Inc., 2010, JMP ver.10, http://www.jmp.com/en_us/software/jmp.html.

Cited by

  1. Cavitation Visualization Test for Shape Optimization of Bottom Plug in Reversing Valve vol.40, pp.11, 2016, https://doi.org/10.3795/KSME-A.2016.40.11.913