tailieunhanh - Heat Transfer Handbook part 45

Heat Transfer Handbook part 45. The Heat Transfer Handbook provides succinct hard data, formulas, and specifications for the critical aspects of heat transfer, offering a reliable, hands-on resource for solving day-to-day issues across a variety of applications. | 432 FORCED CONVECTION INTERNAL FLOWS k Tmax - To Pr4 99 f 1 l Be47 99 HLW - L2 DopJ with A PL2 Be ------- a for hie ranee 104 ReDh 106 106 ReL 108 1011 Be 1016 Turbulent flow and entrance lengths X Xt D - 10 D Turbulent flow friction factor f 5 2 x 104 Rid 105 see Fig. Turbulent flow heat transfer f St Pr2 3 for Pr Nud hD 5 Pr1 3 forPr 2 x 104 ReD 106 Nud 5 Pr where n for heating hie fluid and n for cooling the fluid in hie ranee L 60 D Pr 120 2500 ReD x 105 x Nud Pr1 3 fl0 tn the rrnne SUMMARY OF FORCED CONVECTION RELATIONSHIPS 433 Pr 16 700 ReD 104 Here P0 p T0 T0 is the wall temperature p p Tm Tm is the bulk temperature 4u _ f 2 ReD Pr__ UD 900 ReD - 1 10Pr f 2 1 2 Pr2 3 - 1 iu f 2 ReD Pr UD f 2 1 2 Pr2 3 - 1 where Pr 106 4000 ReD 5 x 106 and f from Fig. . xt f 2 ReD - 103 Pr Nud ---------------- ---- ------ 1 f 2 1 2 Pr2 3 - 1 where Pr 106 2300 ReD 5 x 106 and f from Fig. . Nud Re - 100 Pr0 4 where Pr 104 ReD 5 x 106 Nud ReD87 - 280 Pr0 4 where Pr 500 3x 103 ReD 106 Nud q constant T0 constant where for eqs. and Pr 104 ReD 106 434 FORCED CONVECTION INTERNAL FLOWS Total heat transfer rate q hAw ATlm Isothermal wall A Tin A TOut lm ln Arin ATout q mCp ATn 1 e hAw mcp Uniform heat flux ATim A Tn ATOut NOMENCLATURE Roman Letter Symbols A cross-sectional area m2 Aw wall area m2 a pressure at point 1 Pa B cross-section shape number dimensionless Be Bejan number dimensionless b length m b pressure at point 2 Pa C cross-section shape factor dimensionless Cf x local skin friction coefficient dimensionless cp specific heat at constant pressure J kg-K D spacing diameter m Dh hydraulic diameter m f friction factor .

• Điện - Điện tử
• Cẩm nang truyền nhiệt
• nghiên cứu ứng dụng
• truyền nhiệt trong các thiết bị điện tử
• khái niệm truyền nhiệt và ứng dụng
• nhiệt động NIST