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FC_sphere

 

 

The procedure FC_sphere(Fluid$, T_s, T_infinity, P, D : h, Nusselt, Ra) returns the heat transfer coefficient, Nusselt number and Rayleigh number for an isothermal sphere of diameter D submerged in a fluid and subjected to gravity. The units of the inputs and outputs depend on the unit settings in EES.  The magnitude of gravity is assumed to be 9.807 [m/s^2]. 

 

Inputs:

Fluid$ - string name of any fluid in the EES database. The fluid can be an ideal gas or a real fluid

T_s - surface temperature of the plate in [C], [K], [F], or [R].

T_infinity - bulk temperature of the fluid in [C], [K], [F], or [R].

P -  ambient pressure in [Pa], [kPa], [bar], [MPa], [atm], or [psia]

D - diameter of the sphere [m] or [ft]

 

Outputs:

h -  heat transfer coefficient in [W/m^2-K] or [Btu/hr-ft^2-R]

Nusselt - Nusselt number [-]

Ra - Rayleigh number [-]

 

Notes:

The procedure FC_sphere determines the fluid properties and calculates the Rayleigh and Prandtl numbers.  Once these values are found, the non-dimensional procedure FC_sphere_ND is called to calculate the Nusselt number. FC_sphere, in turn, uses the Nusselt number to calculate the coefficient of heat transfer as described in section 6.2.3 of Nellis and Klein.

 

Example:    

$UnitSystem SI C deg  J Pa

P=101300 [Pa]  

T_s=45 [C]

T_infinity=30 [C]

D=0.09 [m]

Fluid$='water'

Call FC_sphere(Fluid$, T_s, T_infinity, P, D : h, Nusselt, Ra)

 

{Solution: h=519.4 [W/m^2-K], Nusselt=76.09, Ra=3.855E+08}

 

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