# 응축기용 낮은 핀관의 내부 나선 홈에 의한 응축 열전달 성능과 압력손실에 관한 연구

• 한규일 (부경대학교 제어기계공학과) ;
• 조동현 (대진대학교기계설계공학과)
• Published : 1998.06.01

#### Abstract

Heat transfer performance improvement by fin and groovs is studied for condensation of R-11 on integral-fin tubes. Eight tubes with trapczodially shaped integral-fins having fin density from 748 to 1654fpm(fin per meter) and 10, 30 grooves are tested. A plain tube having the same diameter as the finned tubes is also used for comparison. R-11 condensates at saturation state of 32 $^{\circ}C$ on the outside tube surface coded by inside water flow. All of test data are taken at steady state. The heat transfer loop is used for testing singe long tubes and cooling is pumped from a storage tank through filters and folwmeters to the horizontal test section where it is heated by steam condensing on the outside of the tubes. The pressure drop across the test section is measured by menas pressure gauge and manometer. The results obtained in this study is as follows : 1. Based on inside diameter and nominal inside area, overall heat transfer coefficients of finned tube are enhanced up to 1.6 ~ 3.7 times that of a plain tube at a constant Reynolds number. 2. Friction factors are up to 1.6 ~ 2.1 times those of plain tubes. 3. The constant pumping power ratio for the low integral-fin tubes increase directly with the effective area to the nominal area ratio, and with the effective area diameter ratio. 4. A tube having a fin density of 1299fpm and 30 grooves has the best heat transfer performance.

#### References

1. ASME J. of Heat Transfer v.101 Analysis of Tubulent Flow and Heat Transfer in Internally Finnod Tubes and Annuli Patankar, S. V.;Lvanovic, M.;Sparrow E. .M.
2. Int. J. Heat Mass Transfer v.15 Application of Rough Surface to Heat Exchanger Design Webb, R. L.;Eckert, E. R. G.
3. The American Society of Mechanical Engineers for Presentation at the AICHE - ASME Heat Transfer Conference v.11-13 Heat Transfer and Pressure Drop of Internally Finned tubes in Laminar Oil Flow Watkinson, A. P.;Miletti, D. I.;Kubanek, G. R.
4. Heat Transfer- Fourth Edition Holman, J. P.
5. Thermal Eng.(USSR) v.17 no.2 Omatskii, A. P.;Shcherbakob, V. K.;Semena, M. G.
6. Int. J. Heat Mass Transfer v.9 Condensation Heat Transfer in the Presence of Noncondensables, Interifacial Resistance, Superheatiog, Variable Properties, and Diffusion Minkowycz, W. J.;Sparrow, E. M.
7. Heat Transfereng. v.2 no.1 Tube-Side Heat Transfer and Pressure Drop for Tubes Having Helical Internal Ridging with Turbulent /Transitional Flow of Single Phase Fluid Par 1. Single-Helix Rdiging Withers, James G.
8. AICHE SYMPOSIUM SERIES v.69 no.131 Turbulent Heat Transfer and Pressure Drop in Internally Finned Tubes Watkinson, A. P.;miletti, D. I.;Tarassoff, P.
9. Int. J. Heat Transfer v.21 An Investigation of Heat Transfer and Friction for Rib Roughened Surfaces Han, J. C.;Clicksman, L. R.;Rohsenow, W. M.
10. Paper Presented at the Semi-Annual ASHRAE Meeting Heat Transfer and Pressure and Pressure Drop of Forge - Fin Tubes in Turbulent Air Flow Watkinson, A. P.;Miletti, D. L.;Kubanek, G. R.
11. Ph. D. thesis, Department of Mechanicla Engineering, Aeronautical Engineering and Mechanics, Rensselaer Polytechnic Institute Heat Transfer Enhancement of Intube Flows in Process Heat Exchangters by Means of Twisted- Tape Inserts Manglik, R. M.
12. Int. J. Heat Mass Transfer v.21 Rough Annulus Pressure Drop Interpretation of Experiments and Recalculation for Square Ribs Manbach, K.
13. Paper Presented at ASME - AICHE Heat Transfer Conf. Berlges, A. E.;Brown, J. S.;Snider, W. D.