EXPERIMENTAL INVESTIGATION OF NATURAL-CONVECTION FROM VERTICAL HELICAL COILED TUBES

被引:76
作者
ALI, ME [1 ]
机构
[1] HELWAN UNIV,FAC ENGN & TECHNOL,CAIRO,EGYPT
关键词
Laminar flow - Surfaces - Tubes (components) - Turbulent flow;
D O I
10.1016/0017-9310(94)90138-4
中图分类号
O414.1 [热力学];
学科分类号
摘要
An experimental study has been made on steady state natural convection heat transfer from vertical helical coiled tubes. Average heat transfer coefficients were obtained for turbulent natural convection to water. The experiments have been carried out for four coil diameter to tube diameter ratios, for five and ten coil turns, and for five pitch to outer diameter ratios. The data are correlated with the Rayleigh number for two different coil sets. The heat transfer coefficient decreases with coil length for tube diameter d0 = 0.012 m, but increases with coil length for d0 = 0.008 m. A critical D/d0 is obtained for a maximum heat transfer coefficient for tube diameter of 0.012 m with either five or ten coil turns.
引用
收藏
页码:665 / 671
页数:7
相关论文
共 10 条
  • [1] BURMEISTER LC, 1983, CONVECTIVE HEAT TRAN, P543
  • [2] FOGIEL M, 1984, HEAT TRANSFER PROBLE, P768
  • [3] EXPERIMENTS ON NATURAL-CONVECTION HEAT TRANSFER FROM OUTER SURFACE OF A VERTICAL CYLINDER TO LIQUIDS
    FUJII, T
    TAKEUCHI, M
    FUJII, M
    SUZAKI, K
    UEHARA, H
    [J]. INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 1970, 13 (05) : 753 - &
  • [4] GARIMELLA S, 1988, ASME, V110, P329
  • [5] Ito H., 1959, J BASIC ENGINEERIN D, V81, P123, DOI [DOI 10.1115/1.4008390, 10.1115/1.4008390]
  • [6] KREITH F, 1958, PRINCIPLES HEAT TRAN, P335
  • [7] McAdams W.H., 1954, HEAT TRANSMISSION
  • [8] Rogers G, 1964, INT J HEAT MASS TRAN, V7, P1207, DOI [10.1016/0017-9310(64)90062-6, DOI 10.1016/0017-9310(64)90062-6]
  • [9] Seban R.A, 1963, INT J HEAT MASS TRAN, V6, P387, DOI DOI 10.1016/0017-9310(63)90100-5
  • [10] AN EXPERIMENTAL STUDY OF TURBULENT NATURAL CONVECTION BOUNDARY LAYERS
    VLIET, GC
    LIU, CK
    [J]. JOURNAL OF HEAT TRANSFER, 1969, 91 (04): : 517 - +