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Correlations for Convective Heat Transfer

Nov 08 2010 01:20 PM | bspang in Heat Transfer ***** Share this topic:
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Section 4: Forced Convection Flow Across Single Circular Cylinders and Tube Bundles

convection_eq_18

Eq. (18)

 

convection_eq_19

Eq. (19)

 

convection_eq_20

Eq. (20)

D = cylinder diameter, um = free-stream velocity, all properties at fluid bulk mean temperature. Correction for temperature dependent fluid properties see section 4-4.

4-1 Smooth Circular Cylinder

convection_eq_21

Eq. (21)

where: convection_5

 

convection_eq_22

Eq. (22)

Valid over the ranges 10 < Rel < 107 and 0.6 < Pr < 1000.

4-2 Tube Bundle

Transverse pitch ratio convection_6

Longitudinal pitch ratio convection_7

Void ratio convection_8for b > 1

convection_9for b < 1

Nu0,bundle = fANul,0 (Gnielinski)

Nul,0 according to section 4-1 with convection_10instead of Rel.

Arrangement factor fA depends on tube bundle arrangement.

convection_11

In line arrangement: convection_eq_23

Eq. (23)

 

convection_12

Staggered arrangement: convection_eq_24

Eq. (24)

 

4-3 Finned Tube Bundle

convection_13

convection_14

convection_15

In-line tube bundle arrangement:

convection_eq_25Eq. (25)

Staggered tube bundle arrangement:

convection_eq_26Eq. (26)

 

4-4 Effects of Property Variation with Temperature

Liquids:

convection_eq_27Eq. (27)

 

convection_eq_28Eq. (28)

Subscript w: at wall temperature, without subscript: at mean fluid temperature.

Gases:

convection_eq_29Eq. (29)

 

convection_eq_30Eq. (30)

Temperatures in Kelvin.





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