Heat Analysis and Thermodynamic Effects Part 6

Tham khảo tài liệu 'heat analysis and thermodynamic effects part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Optimal Shell and Tube Heat Exchangers Design 139 Area for flow through window Sw It is given by the difference between the gross window area Swg and the window area occupied by tubes Swt Sw Swg - Swt 92 where ._ Ds 2 Swg y- I y I y I y arccosl 1 - 2-e- I -11 - 2-e- L 1 -11 - 2-e- I I D. I I D. n I D. I s s 93 and Swt n. 8 1 - Fe x. D. 2 94 Shell-side heat transfer coefficient for an ideal tube bank hoi j CPs .ms ks y2 3 95 hot J I Sm I Cp. ụs J Correction factor for baffle configuration effects Jc Je Fe 0 54. 1 - Fe 0-345 96 Correction factor for baffle-leakage effects Jl Ssb Stb y 97 Jl a 1 -a .expI- 2 2. -----I 97 I Sm J where a 0 1 Ssb y Ssb Stb J 98 Correction factor for bundle-bypassing effects Jb Jb exp - 0 99 Assuming that very laminar flow is neglected Res 100 it is not necessary to use the correction factor for adverse temperature gradient buildup at low Reynolds number. Shell-side heat transfer coefficient hs hs hot . 100 Pressure drop for an ideal cross-flow section APbi .Ne. m f bi p Sm2 101 140 Heat Analysis and Thermodynamic Effects Pressure drop for an ideal window section APwi P . 2 0 -m Wi Sm 102 Correction factor for the effect of baffle leakage on pressure drop Rl where Rl exp -1 33 1 - s _ Y SbiSL Ìk I Ssb Stb JI Sm J 103 Ssb 1 k -0 1 S 1 0 8 I Ssb Stb J 104 Correction factor for bundle bypass Rb Rb exp - 1 Pressure drop across the Shell-side APs . Ncw 1 Ps 2. 1 4 .Rb Nb 1 . Nb. I Nc J 105 106 This value must respect the pressure drop limit fixed before the design P. P. design 107 Tube-side Reynolds number Ret .Ntp Re ---T- TT . .N 108 Friction factor for the tube-side flt 1 Tt -4 log 2 7 Re d ex 109 where e is the roughness in mm. Prandtl number for the tube-side Prt Pr p Cp k 110 Nusselt number for tube-side Nut Nu 0 027. Re 0-8. Pr 13 111 Tube-side heat transfer coefficient ht Optimal Shell and Tube Heat Exchangers Design 141 k Nu .k din dd in ex .