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PF strip-fin ND functions

 

 

The procedure: 

 

CHX_ND_PF_strip_fin(TypeHX$, Re: f, j_H)

 

provides the dimensionless performance associated with a plain fin - strip fin compact heat exchanger surface.  These data are from Kays and London (1994).

 

Inputs

TypeHX$: string identifying the geometry 

 1/8-15.2:  'PF_strip-fin_18_152'

 1/8-13.95: 'PF_strip-fin_18_1395'

  1/8-15.61: 'PF_strip-fin_18_1561'

  1/8-19.86: 'PF_strip-fin_18_1986'

  1/9-22.68: 'PF_strip-fin_19-2268'

  1/9-25.01: 'PF_strip-fin_19-2501'

  1/9-24.12: 'PF_strip-fin_19_2412'

  1/10-27.03: 'PF_strip-fin_110_2703'

  1/10-19.35: 'PF_strip-fin_110_1935'

  1/10-19.74: 'PF_strip-fin_110_1974'

  3/32-12.22: 'PF_strip-fin_332_1222'

  1/2-11.94(D): 'PF_strip-fin_12_1194D'

  1/4-15.4(D): 'PF_strip-fin_14_154D'

  1/6-12.18(D): 'PF_strip-fin_16_11218D'

  1/7-15.75(D): 'PF_strip-fin_17_1575D'

  1/8-16.00(D): 'PF_strip-fin_18_1600D'

  1/8-16.12(D): 'PF_strip-fin_18_1612D'

  1/8-19.82(D): 'PF_strip-fin_18_1982D'

  1/8-20.06(D): 'PF_strip-fin_18_2006D'

  1/8-16.12(T): 'PF_strip-fin_18_1612T'

 

Re: Reynolds number (-)

 

Outputs

f:  friction factor (-)

j_H: Colburn j function for heat transfer (-)

 

The Reynolds number is defined according to:

 

 

where m is the viscosity, Dh is the hydraulic diameter, and G is the mass flux.  The hydraulic diameter is defined as:

 

 

where Ac is the minimum free flow area, A is the total heat transfer area, and L is the length in the flow direction.

 

The mass flux is defined as: 

 

 

where is the mass flow rate.  

 

The friction factor is defined as:

 

 

where r is the density, and to is the equivalent shear stress, defined as:

 

 

where DP is the pressure drop due to friction and form drag in the core.

 

Example

TypeHX$= 'PF_strip-fin_18_152'

Re=1000

Call chx_nd_pf_strip_fin(TypeHX$, Re: f, j_H)

 

{Solution is:

f = 0.07204, j_H = 0.01363}

 

Related procedures include:

Geometry Functions

Coefficient of Heat transfer

Pressure Drop