# CPVC 배관 동파방지용 열선의 위치 선정을 위한 비정상 열전달 수치해석

• 최명영 (한국화재보험협회 방재시험연구원) ;
• 최형권 (서울과학기술대학교 기계자동차공학과)
• Accepted : 2015.11.26
• Published : 2015.12.31
• 59 175

#### Abstract

In this paper, a numerical experiment was conducted to find out the optimal location of electrical heat trace for anti-freeze of water inside the CPVC pipe for fire protection. The unsteady incompressible Navier-Stokes equations coupled with energy equation were solved. Since the conduction equation of pipe was coupled with the natural convection of water, the analysis of conjugate heat transfer was conducted. A commercial code (ANSYS-FLUENT) based on SIMPLE-type algorithm was used for investigating the unsteady flows and temperature distributions in water region. From the present numerical experiment, it has been found that the vector field of water inside the PVC pipe is opposite to the case of steel because of the huge difference of material properties of the two pipes. Furthermore, it was found that the lowest part of the pipe was an optimal position for electrical heat trace since the minimum water temperature of the case was higher than those of the other cases.

#### Keywords

Heat tracing;CPVC;CFD;Natural convection;Conjugate heat transfer

#### Acknowledgement

Supported by : 서울과학기술대학교

#### References

1. M. Y. Choi, D. W. Lee and H. G. Choi, "Numerical Analysis of Unsteady Heat Transfer for the Location Selection of Anti-freeze for the Fire Protection Piping with Electrical Heat Trace", Fire Science and Engineering, Vol. 28, No. 1, pp. 52-57 (2014).
2. J. S. Nam, Y. S. Lee, Y. H. Kim and S. Y. Won, "A Characteristic Comparison of Copper Pipe and Strain less Pipe used in Fire Protection System", Fire Science and Engineering, Vol. 28, No. 4, pp. 200-206 (2010).
3. A. K. De and A. Dalal, "A Numerical Study of Natural Convection Around a Square, Horizontal, Heated Cylinder Placed in a Enclosure", Int. J. Heat and Mass Transfer, Vol. 49, Issues 23-24, pp. 4608-4623 (2006). https://doi.org/10.1016/j.ijheatmasstransfer.2006.04.020
4. M. Y. Ha, I. K. Kim, H. S. Yoon and S. S. Lee, "Unsteady Fluid Flow and Temperature Fields in a Horizontal Enclosure with an adiabatic Body", Physics of Fluids, Vol. 14, No. 9, pp. 3189-3202 (2002). https://doi.org/10.1063/1.1497168
5. M. Y. Ha, I. K. Kim, H. S. Yoon, K. S. Yoon, J. R. Lee, S. Balachandar and H. H. Chum, "Two-Dimensional and Unsteady Natural Convection in a Horizontal Enclosure with a Square Body", Numerical Heat Transfer, Vol. 41, pp. 183-210 (2002). https://doi.org/10.1080/104077802317221393
6. R. Kumar, "Study of Natural Convection in Horizontal Annuli", International Journal of Heat and Mass Transfer, Vol. 31, No. 6, pp. 1137-1148 (1988). https://doi.org/10.1016/0017-9310(88)90056-7
7. T. H. Kuehn and R. J. Goldstein, "Numerical Solution to the Navier-Stokes Equations for Laminar Natural Convection about a Horizontal Isothermal Circular Cylinder", International Journal of Heat and Mass Transfer, Vol. 23, No. 7, pp. 971-979 (1980). https://doi.org/10.1016/0017-9310(80)90071-X
8. KS L 9016, Test methods for thermal transmission properties of thermal insulations (2012).
9. R. R. Gilpin, "Ice Formation in a Pipe Containing Flows in the Transition and Turbulent Regimes", J. Heat Transfer, Vol. 103, pp. 363-368 (1981). https://doi.org/10.1115/1.3244467
10. ANSI/IEEE Std. 515, Standard for the Testing, Design, Installation and Maintenance of Electrical Resistance Heat Tracing for Industrial Applications (2005).
11. ANSI/IEEE Std. 844, Recommended Practice for Electrical Impedance, Induction, and Skin Effect Heating of Pipelines and Vessels (2000).
12. ANSI/NECA 202, Recommended Practice for Installing and Maintaining Industrial Heat Tracing Systems (2001).
13. NFPA 70, National Electrical Code 427.1 (2008).
14. ANSYS Co., ANSYS Fluent User's Guide 13.2.4 (2012).