A CHF Model for Uniformly Heated Vertical Tubes at High Pressures

W.Jaewoo Shim; Joo-Yong Park

Journal of Industrial and Engineering Chemistry, Vol.9, No.6, 792-797, November, 2003

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A CHF Model for Uniformly Heated Vertical Tubes at High Pressures

W.Jaewoo Shim^†, and Joo-Yong Park

Department of Chemical Engineering, Dankook University, Seoul 140-714, Korea

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In this study. a total of 2870 high pressure (70 bar ≤ P ≤ 206 bar) data points of critical heat flux (CHF) in uniformly heated round vertical tubes for water were collected from 5 different published sources. The data consisted of following parameter ranges: 28.07 ≤ G (mass flux) ≤ 10565.03 kg/m²s, 0.00191 ≤ D (diameter) ≤ 0.04468 m, 0.04 ≤ L (length) ≤ 4.966 m, 0.14 ≤ q_c(CHF) ≤ 9.94 MW/m₂, and -0.85 ≤ X (exit qualities) ≤ 1.22. With these data a comparative analysis is made on available correlations, and a new correlation is presented. The new high pressure CHF correlation, as in the low and medium pressure cases of earlier studies, comprised of local variables, namely, "true" mass quality, mass flux, tube diameter, and two parameters as a function of pressure only. This study reaffirms our earlier findings that by incorporating "true" mass quality in the local condition hypothesis, the prediction of CHF under these conditions can be obtained quite accurately. overcoming the difficulties of flow instability and buoyancy effects that are inherent in the phenomena. The new correlation predicts the CHF data significantly better than those currently available correlations, with average error 0.12% and rms error 13.52% by the heat balance method.

Keywords:CHF (critical heat flux);dryout;burnout;heat transfer equipment;true mass quality

[References]

Shim WJ, Lee SW, Kim O, J. Ind. Eng. Chem., 9(3), 323 (2003)
Shim WJ, Joo SK, J. Ind. Eng. Chem., 8(3), 268 (2002)
Becker KM, Strand G, Osterdahl C, Royal Institute of Technology, Laboratory of Nuclear Engineering, KTH-NEL-14, Sweden (1971)
Lee DH, Obertelli JD, AEEW-R213, UK Atomic Energy Authority (1963)
Thompson B, Macbeth RV, AEEW-R 356, UK Atomic Energy Authority (1964)
Swenson HS, Caver JR, Karkarla CR, ASME, 62-WA-297 (1963)
Griffel J, NYO-187-7, Columbia University (1965)
Bowring RW, AEEW-R 789, UK Atomic Energy Authority (1972)
Shah MM, Heat Fluid Flow, 8, 326 (1987)
Tong LS, J. Nucl. Energy, 21, 241 (1967)
Deng Z, Ph.D. Thesis, Columbia University, New York, U.S.A. (1998)
Jafri T, Ph.D. Thesis, Columbia University, New York, U.S.A. (1993)
Saha P, Zuber N, Proceeding of the 5th Int. Heat Transfer Conference, pp. 175-179, Tokyo, Japan (1974)

[Referenced By]

[1] Shim WJ, Lee SW, Kim O, J. Ind. Eng. Chem., 9(3), 323 (2003)

[2] Shim WJ, Joo SK, J. Ind. Eng. Chem., 8(3), 268 (2002)

[3] Becker KM, Strand G, Osterdahl C, Royal Institute of Technology, Laboratory of Nuclear Engineering, KTH-NEL-14, Sweden (1971)

[4] Lee DH, Obertelli JD, AEEW-R213, UK Atomic Energy Authority (1963)

[5] Thompson B, Macbeth RV, AEEW-R 356, UK Atomic Energy Authority (1964)

[6] Swenson HS, Caver JR, Karkarla CR, ASME, 62-WA-297 (1963)

[7] Griffel J, NYO-187-7, Columbia University (1965)

[8] Bowring RW, AEEW-R 789, UK Atomic Energy Authority (1972)

[9] Shah MM, Heat Fluid Flow, 8, 326 (1987)

[10] Tong LS, J. Nucl. Energy, 21, 241 (1967)

[11] Deng Z, Ph.D. Thesis, Columbia University, New York, U.S.A. (1998)

[12] Jafri T, Ph.D. Thesis, Columbia University, New York, U.S.A. (1993)

[13] Saha P, Zuber N, Proceeding of the 5th Int. Heat Transfer Conference, pp. 175-179, Tokyo, Japan (1974)