PF strip-fin ND functions
Missing image: pf_strip-fin_ndfunction.bmp
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 
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: