Remove IndepVarComp from heat exchanger model so users can connect th…

…ings to the DV values (#61)

* Remove IndepVarComp from heat exchanger model so users can connect things to the DV values

* Remove copied HXGroup internals from tests

openconcept/thermal/heat_exchanger.py

@@ -1,5 +1,5 @@
 import numpy as np
-from openmdao.api import ExplicitComponent, IndepVarComp, Group
+from openmdao.api import ExplicitComponent, Group
 from openconcept.utilities import DVLabel
 
 
@@ -1393,37 +1393,37 @@ def initialize(self):
     def setup(self):
         nn = self.options["num_nodes"]
 
-        iv = self.add_subsystem("dv", IndepVarComp(), promotes_outputs=["*"])
-        iv.add_output("case_thickness", val=2.0, units="mm")
-        iv.add_output("fin_thickness", val=0.102, units="mm")
-        iv.add_output("plate_thickness", val=0.2, units="mm")
-        iv.add_output("material_k", val=190, units="W/m/K")
-        iv.add_output("material_rho", val=2700, units="kg/m**3")
-
-        # iv.add_output('mdot_cold', val=np.ones(nn)*1.5, units='kg/s')
-        # iv.add_output('rho_cold', val=np.ones(nn)*0.5, units='kg/m**3')
-        # iv.add_output('mdot_hot', val=0.075*np.ones(nn), units='kg/s')
-        # iv.add_output('rho_hot', val=np.ones(nn)*1020.2, units='kg/m**3')
-
-        # iv.add_output('T_in_cold', val=np.ones(nn)*45, units='degC')
-        # iv.add_output('T_in_hot', val=np.ones(nn)*90, units='degC')
-        # iv.add_output('n_long_cold', val=3)
-        # iv.add_output('n_wide_cold', val=430)
-        # iv.add_output('n_tall', val=19)
-
-        iv.add_output("channel_height_cold", val=14, units="mm")
-        iv.add_output("channel_width_cold", val=1.35, units="mm")
-        iv.add_output("fin_length_cold", val=6, units="mm")
-        iv.add_output("cp_cold", val=1005, units="J/kg/K")
-        iv.add_output("k_cold", val=0.02596, units="W/m/K")
-        iv.add_output("mu_cold", val=1.789e-5, units="kg/m/s")
-
-        iv.add_output("channel_height_hot", val=1, units="mm")
-        iv.add_output("channel_width_hot", val=1, units="mm")
-        iv.add_output("fin_length_hot", val=6, units="mm")
-        iv.add_output("cp_hot", val=3801, units="J/kg/K")
-        iv.add_output("k_hot", val=0.405, units="W/m/K")
-        iv.add_output("mu_hot", val=1.68e-3, units="kg/m/s")
+        # Set the default values for promoted variables
+        self.set_input_defaults("case_thickness", val=2.0, units="mm")
+        self.set_input_defaults("fin_thickness", val=0.102, units="mm")
+        self.set_input_defaults("plate_thickness", val=0.2, units="mm")
+        self.set_input_defaults("material_k", val=190, units="W/m/K")
+        self.set_input_defaults("material_rho", val=2700, units="kg/m**3")
+
+        # self.set_input_defaults('mdot_cold', val=np.ones(nn)*1.5, units='kg/s')
+        # self.set_input_defaults('rho_cold', val=np.ones(nn)*0.5, units='kg/m**3')
+        # self.set_input_defaults('mdot_hot', val=0.075*np.ones(nn), units='kg/s')
+        # self.set_input_defaults('rho_hot', val=np.ones(nn)*1020.2, units='kg/m**3')
+
+        # self.set_input_defaults('T_in_cold', val=np.ones(nn)*45, units='degC')
+        # self.set_input_defaults('T_in_hot', val=np.ones(nn)*90, units='degC')
+        # self.set_input_defaults('n_long_cold', val=3)
+        # self.set_input_defaults('n_wide_cold', val=430)
+        # self.set_input_defaults('n_tall', val=19)
+
+        self.set_input_defaults("channel_height_cold", val=14, units="mm")
+        self.set_input_defaults("channel_width_cold", val=1.35, units="mm")
+        self.set_input_defaults("fin_length_cold", val=6, units="mm")
+        self.set_input_defaults("cp_cold", val=1005, units="J/kg/K")
+        self.set_input_defaults("k_cold", val=0.02596, units="W/m/K")
+        self.set_input_defaults("mu_cold", val=1.789e-5, units="kg/m/s")
+
+        self.set_input_defaults("channel_height_hot", val=1, units="mm")
+        self.set_input_defaults("channel_width_hot", val=1, units="mm")
+        self.set_input_defaults("fin_length_hot", val=6, units="mm")
+        self.set_input_defaults("cp_hot", val=3801, units="J/kg/K")
+        self.set_input_defaults("k_hot", val=0.405, units="W/m/K")
+        self.set_input_defaults("mu_hot", val=1.68e-3, units="kg/m/s")
 
         dvlist = [
             ["ac|propulsion|thermal|hx|n_wide_cold", "n_wide_cold", 430, None],