Advances in heat exchanger models

docs/src/propulsion/gascalc.md

@@ -25,9 +25,9 @@ engine.gas_delh(alpha, n, po, to, ho, so, cpo, ro, delh, epol)
 
 engine.gas_delhd(alpha, n, po, to, ho, so, cpo, ro, delh, epol)
 
-engine.gas_burn(alpha, beta, gamma, n, ifuel, to, tf, t)
+engine.gas_burn(alpha, beta, gamma, n, ifuel, to, tf, t, hvap)
 
-engine.gas_burnd(alpha, beta, gamma, n, ifuel, to, tf, t)
+engine.gas_burnd(alpha, beta, gamma, n, ifuel, to, tf, t, hvap)
 
 engine.gas_mach(alpha, n, po, to, ho, so, cpo, ro, mo, m, epol)
 

example/cryo_input.toml

@@ -49,6 +49,8 @@ name = "TASOPT Model with cryo fuel and HX"
     fuel_in_wingcen = false # Is fuel stored in wing center box?
     fuel_usability_factor = 0.90 # fraction of max fuel volume that is usable
 
+    fuel_enthalpy_vaporization = 0.0 #J/kg, latent heat of vaporization of fuel
+
 [Fuel.Storage]
     tank_placement = "rear" #Location of tank in fuselage. Choices are "front", "rear", or "both".
 
@@ -482,8 +484,8 @@ name = "TASOPT Model with cryo fuel and HX"
 [Propulsion.HeatExchangers] #Default model does not have heat exchangers in the propulsion system
     recirculation_flag = 1
     recirculation_temperature = 200
-    latent_heat = 0
-    core_inner_diameter = 0.564
+    core_inner_diameter = 0.2
+    added_mass_frac = 1.0
 
     precooler_order = 1
     precooler_effectiveness = 0

example/example_regional.toml

@@ -48,6 +48,7 @@
 
     fuel_temp = 280.0
     fuel_density = 817.0 #kg/m3
+    fuel_enthalpy_vaporization = 0.0 #J/kg, latent heat of vaporization of fuel
 
 [Mission]
     N_missions = 1 # Number of missions to be modeled (first mission is the design mission)
@@ -447,8 +448,8 @@
 [Propulsion.HeatExchangers] #Default model does not have heat exchangers in the propulsion system
     recirculation_flag = 0
     recirculation_temperature = 0
-    latent_heat = 0
     core_inner_diameter = 0
+    added_mass_frac = 0.0
 
     precooler_order = 0
     precooler_effectiveness = 0

example/example_widebody.toml

@@ -50,6 +50,7 @@
 
     fuel_temp = 280.0
     fuel_density = 810.0 #kg/m3
+    fuel_enthalpy_vaporization = 0.0 #J/kg, latent heat of vaporization of fuel
 
 [Mission]
     N_missions = 1 # Number of missions to be modeled (first mission is the design mission)
@@ -451,8 +452,8 @@
 [Propulsion.HeatExchangers] #Default model does not have heat exchangers in the propulsion system
     recirculation_flag = 0
     recirculation_temperature = 0
-    latent_heat = 0
     core_inner_diameter = 0
+    added_mass_frac = 0.0
 
     precooler_order = 0
     precooler_effectiveness = 0

src/IO/default_input.toml

@@ -53,6 +53,7 @@
 
     fuel_temp = 280.0
     fuel_density = 817.0 #kg/m3
+    fuel_enthalpy_vaporization = 0.0 #J/kg, latent heat of vaporization of fuel
 
 [Fuel.Storage] #Default fuselage fuel storage parameters for cryogenic fuels
     tank_placement = "rear" #Location of tank in fuselage. Choices are "front", "rear", or "both".
@@ -502,8 +503,8 @@
 [Propulsion.HeatExchangers] #Default model does not have heat exchangers in the propulsion system
     recirculation_flag = 0
     recirculation_temperature = 0
-    latent_heat = 0
     core_inner_diameter = 0
+    added_mass_frac = 0.0
 
     precooler_order = 0
     precooler_effectiveness = 0

src/IO/read_input.jl

@@ -159,6 +159,8 @@ end
 pari[iifwing]  = readfuel("fuel_in_wing")
 pari[iifwcen]  = readfuel("fuel_in_wingcen")
 parg[igrWfmax] = readfuel("fuel_usability_factor")
+pare[iehvap, :, :] .= readfuel("fuel_enthalpy_vaporization") #Heat of vaporization of the fuel
+pare[iehvapcombustor, :, :] .= readfuel("fuel_enthalpy_vaporization") #Heat of vaporization of fuel, if vaporized in combustor
 
 # Setup mission variables
 ranges = readmis("range")
@@ -921,9 +923,10 @@ dweight = dprop["Weight"]
 
 HEx = readprop("HeatExchangers")
 dHEx = dprop["HeatExchangers"]
+    parg[igHXaddmassfrac] = read_input("added_mass_frac", HEx, dHEx)
+
     pare[iefrecirc, :, :] .= read_input("recirculation_flag", HEx, dHEx)
     pare[ierecircT, :, :] .= read_input("recirculation_temperature", HEx, dHEx)
-    pare[iehlat, :, :] .= read_input("latent_heat", HEx, dHEx)
     pare[ieDi, :, :] .= read_input("core_inner_diameter", HEx, dHEx)
 
     pare[iePreCorder, :, :] .= read_input("precooler_order", HEx, dHEx)

src/engine/gascalc.jl

@@ -569,7 +569,7 @@ function gas_delhd(alpha, n, po, to, ho, so, cpo, ro, delh, epol)
 end # gas_delhd
 
 """
-    gas_burn(alpha, beta, gamma, n, ifuel, to, tf, t)
+    gas_burn(alpha, beta, gamma, n, ifuel, to, tf, t, hvap)
 
 Calculates fuel/air mass fraction in combustion with specified start and end temperatures to,t .
 Calculates mass fractions of post-combustion constituents
@@ -583,13 +583,14 @@ Calculates mass fractions of post-combustion constituents
     - `to`: starting air temperatur
     - `tf`: starting fuel temperature
     - `t`: temperature of combustion products
+    - `hvap`: fuel enthalpy of vaporization
       
     **Output:**
     `f`: fuel/air mass fraction
     `lambda(.)`: mass fractions for combustion product constituents
 
 """
-function gas_burn(alpha, beta, gamma, n, ifuel, to, tf, t)
+function gas_burn(alpha, beta, gamma, n, ifuel, to, tf, t, hvap)
 
       nm = n - 1
       so, s_t, ho, h_t, cpo, ro = gassum(alpha, nm, to)
@@ -599,7 +600,7 @@ function gas_burn(alpha, beta, gamma, n, ifuel, to, tf, t)
 
       #---- add on fuel contribution to hf and hc, which gassum cannot index via ifuel
       si, s_t, hi, h_t, cpi, ri = gasfun(ifuel, tf)
-      hf = hf + hi * beta[n]
+      hf = hf + (hi - hvap) * beta[n]
 
       #sb, s_t, hb, h_t, cpb, rb = gasfun(ifuel, t)
       #hc = hc + hb * gamma[n] #Add contribution from unburnt fuel when etab < 1
@@ -617,7 +618,7 @@ function gas_burn(alpha, beta, gamma, n, ifuel, to, tf, t)
 end # gas_burn
 
 """
-    gas_burnd(alpha, beta, gamma, n, ifuel, to, tf, t)
+    gas_burnd(alpha, beta, gamma, n, ifuel, to, tf, t, hvap)
     
 Same as gas_burn, but also returns derivatives.
 
@@ -631,6 +632,7 @@ Same as gas_burn, but also returns derivatives.
     - `to`: starting air temperatur
     - `tf`: starting fuel temperature
     - `t`: temperature of combustion products
+    - `hvap`: fuel enthalpy of vaporization
       
     **Output:**
     `f`: fuel/air mass fraction
@@ -641,7 +643,7 @@ Same as gas_burn, but also returns derivatives.
     `l_t`: 
 
 """
-function gas_burnd(alpha, beta, gamma, n, ifuel, to, tf, t)
+function gas_burnd(alpha, beta, gamma, n, ifuel, to, tf, t, hvap)
 
       nm = n - 1
       so, s_t, ho, ho_to, cpo, ro = gassum(alpha, nm, to)
@@ -651,7 +653,7 @@ function gas_burnd(alpha, beta, gamma, n, ifuel, to, tf, t)
 
       #---- add on fuel contribution to hf and hc, which gassum cannot index via ifuel
       si, s_t, hi, hi_tf, cpi, ri = gasfun(ifuel, tf)
-      hf = hf + hi * beta[n]
+      hf = hf + (hi - hvap) * beta[n]
       hf_tf = hf_tf + hi_tf * beta[n]
 
       #sb, s_t, hb, hb_t, cpb, rb = gasfun(ifuel, t)