Flow_Boiling_Hamilton
Procedure Flow_Boiling_Hamilton(Fluid$,P_sat, G, d, x, q``: h, T_w ) implements the Hamilton correlation to determine the heat transfer coefficient for an evaporating refrigerant in a micro-tube heat exchanger. The correlation is applicable to pure refrigerants and blends. The correction for blends uses the approximation reported in Kedzierski et al. (2015).
Inputs
Fluid$ - string variable representing a real fluid in the EES data base.
P_sat - the saturation pressure of the incoming vapor in [Pa, kPa, bar, MPa, psi,atm] (units depend on unit system selected in EES).
G - mass velocity, i.e., the ratio of the mass flow rate to the cross-sectional area of the tube [kg/s-m^2] or [lbm/hr-ft^2]
d - diameter of the tube [m] or [ft].
x - quality (must be between 0 and 1)
q`` - surface heat flux [W/m^2] or [Btu/hr-ft^2]
Outputs
h - heat transfer coefficient [W/m^2-K] or [Btu/hr-ft^2-F] including convective and nucleate boiling contributions.
T_w - estimated temperature of the inside surface of the tube in [C], [K], [F], or [R].
Notes:
1. Fluid$ must be a provided with a string variable or string constant that is one of the (non-ideal gas) fluids in EES. It uses the correlation developed by Hamilton.
2. At x=1, the procedure returns that heat transfer coefficient expected for a single phase vapor at the given mass velocity and diameter.
3. At high values of quality that would result in a Reynold's number less than 2300, linear interpolation is used between the heat transfer coefficient at a quality that results in Re=2300 and the x=1 value.
4. See also the Flow_Boiling_Shah and Flow_Boiling_Chen correlations.
Example:
$UnitSystem SI K Pa J
$TabStops 3.5 in
$VarInfo h units=W/m^2-K
$VarInfo P_sat units=Pa
$VarInfo q`` units=W/m^2
$VarInfo T_w units=K
$VarInfo U units=W/m^2-K
F$='R22'
T_sat=250 [K] "boiling saturation temperature"
P_sat=pressure(F$,T=T_sat,x=x) "saturation pressure"
G=200 [kg/m^2-s] "mass velocity"
d=0.0172 [m] "tube inner diameter"
x=0.05 "quality"
$VarInfo q`` lower=100 guess=10000
Call flow_boiling_hamilton(F$, P_sat, G, d, x, q``: h, T_w)
q``=U*(T_h-T_sat) "heat flux"
T_h=261 [K] "temperature of fluid on outside of pipe"
h_h=5400 [W/m^2-K] "heat transfer coefficient on outside surface of pipe"
U=(1/h+1/h_h)^(-1) "overall heat transfer coefficient between fluids on either side of the pipe wall"
{Solution
h=1357 [W/m^2-K]
P_sat=216937 [Pa]
q``=11929 [W/m^2]
T_w=258.8 [K]
U=1084 [W/m^2-K]}