1-2 TEMA J Shell and Tube
A shell and tube heat exchanger consists of an outer shell filled with a tube bank. The shell side fluid flows in the shell, around the tube, while the tube side fluid flows through the tubes. There are many shell and tube configurations characterized by, among other things, the shell type and the number and configuration of the shell and tube flows. A 1-2TEMA J shell and tube heat exchanger has a J type shell in which the shell side fluid enters at a center inlets, splits and flows to each end where it leaves at two outlets. There are 2 tube passes. The effectiveness-NTU solution is available for 1-2 TEMA J shell and tube heat exchangers. Solution is from Rohsenow et al.
Note that the 1-2 TEMA J Shell and Tube heat exchanger configuration has an effectiveness that is not monotonically increasing with NTU due to the parallel- and counter-flow nature of the heat exchanger. Therefore it is not possible to determine a unique value of NTU corresponding to an effectiveness.
Example:
$UnitSystem SI Mass J K Pa
$VarInfo UA C_dot_1 C_dot_1 C_dot_min Units = 'W/K'
$VarInfo epsilon NTU Units = '-'
UA = 75 [W/K]
C_dot_1 = 50 [W/K]
C_dot_2 = 30 [W/K]
C_dot_min = Min(C_dot_1,C_dot_2)
NTU = UA/C_dot_min
epsilon=hx('12TEMAJ', Ntu, C_dot_1, C_dot_2, 'epsilon')
{Solution:
epsilon = 0.6828}