Prediction of CHF for Uniformly Heated Vertical tubes at Low Pressures and Low Flows

W. Jaewoo Shim; Ohyoung Kim

Journal of Industrial and Engineering Chemistry, Vol.10, No.4, 516-523, July, 2004

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Prediction of CHF for Uniformly Heated Vertical tubes at Low Pressures and Low Flows

W. Jaewoo Shim^†, and Ohyoung Kim¹

Department of Chemical Engineering, Dankook University, Seoul 140-714, Korea
¹Department of Polymer Science & Engineering, Dankook University, Seoul 140-714, Korea

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The description of critical heat flux (CHF) phenomena under low-pressure (P ≤ 10 bar) and low-flow (G ≤ 300 kg/m²s) conditions is further complicated by the large specific volume of vapor and the effect of buoyancy that are inherent under the conditions. In this study, a total of 834 data points of the CHF for water in a uniformly heated round vertical tube were collected from five different published sources. A comparative analysis is made on the available correlations and a new correlation is presented. The new CHF correlation comprises local variables, namely, the "true" mass quality, mass flux, tube diameter, and two parameters that are a function of pressure only. This study reveals that by incorporating the "true" mass quality into the local condition hypothesis, the prediction of CHF under these conditions can be obtained accurately, while overcoming the difficulties of flow instability and buoyancy effects. The new correlation predicts the CHF data significantly better than do the currently available correlations, within root-mean-square errors of 10.51%, obtained by the heat balance method.

Keywords:CHF (critical heatflux);dryout;burnout;heat transfer equipment

[References]

Mishima K, Nishihara H, Int. J. Heat Mass Transf., 30, 1169 (1987)
Weber P, Johannsen K, Proceeding 9th Int. Heat Transfer Conference, pp. 63-68, Jerusalem (1990)
Chang SH, Baek WP, Bae TM, Nucl. Eng. Design, 132, 225 (1991)
Baek WP, Moon SK, Chang SH, Two-Phase Flow Modelling and Experimentation (1995)
Lee DG, Kim HG, Baek WP, Chang SH, Int. Commun. Heat Mass Transf., 24, 919 (1997)
Kim HC, Baek WP, Chang SH, Nucl. Eng. Design, 199, 49 (2000)
Deng Z, Ph.D. Thesis, Columbia University, New York, U.S.A. (1998)
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)
Thompson B, Macbeth RV, AEEW Rept. R 356, UK Atomic Energy Authority (1964)
Lowdermilk WH, Lanzo CD, Siegel BL, NACA TN 4382 (1958)
Becker KM, Strand G, Report KTH-NEL-14 (1971)
Mishima K, Ph.D. Thesis, Kyoto University, Japan (1984)
Shah MM, Heat Fluid Flow, 8, 326 (1987)
Chang SH, The KAIST CHF data bank (Rev. 3), KAIST-NUSCOL-9601 (1996)
Saha P, Zuber N, Proceeding of the 5th Int. Heat Transfer Conference, pp. 175-179, Tokyo, Japan (1974)
Inasaka F, Nariai H, Nucl. Eng. Design, 163, 225 (1996)

[Related Articles]

[1] Mishima K, Nishihara H, Int. J. Heat Mass Transf., 30, 1169 (1987)

[2] Weber P, Johannsen K, Proceeding 9th Int. Heat Transfer Conference, pp. 63-68, Jerusalem (1990)

[3] Chang SH, Baek WP, Bae TM, Nucl. Eng. Design, 132, 225 (1991)

[4] Baek WP, Moon SK, Chang SH, Two-Phase Flow Modelling and Experimentation (1995)

[5] Lee DG, Kim HG, Baek WP, Chang SH, Int. Commun. Heat Mass Transf., 24, 919 (1997)

[6] Kim HC, Baek WP, Chang SH, Nucl. Eng. Design, 199, 49 (2000)

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

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

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

[10] Thompson B, Macbeth RV, AEEW Rept. R 356, UK Atomic Energy Authority (1964)

[11] Lowdermilk WH, Lanzo CD, Siegel BL, NACA TN 4382 (1958)

[12] Becker KM, Strand G, Report KTH-NEL-14 (1971)

[13] Mishima K, Ph.D. Thesis, Kyoto University, Japan (1984)

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

[15] Chang SH, The KAIST CHF data bank (Rev. 3), KAIST-NUSCOL-9601 (1996)

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

[17] Inasaka F, Nariai H, Nucl. Eng. Design, 163, 225 (1996)