1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
7 ------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
9 This program is free software; you can redistribute it and/or modify it under
10 the terms of the GNU Lesser General Public License as published by the Free Software
11 Foundation; either version 2 of the License, or (at your option) any later
14 This program is distributed in the hope that it will be useful, but WITHOUT
15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
16 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
19 You should have received a copy of the GNU Lesser General Public License along with
20 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
21 Place - Suite 330, Boston, MA 02111-1307, USA.
23 Further information about the GNU Lesser General Public License can also be found on
24 the world wide web at http://www.gnu.org.
26 FUNCTIONAL DESCRIPTION
27 --------------------------------------------------------------------------------
29 Based on Flightgear code, which is based on LaRCSim. This class simulates
33 --------------------------------------------------------------------------------
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47 #include <FGJSBBase.h>
48 #include <input_output/FGXMLElement.h>
49 #include <math/FGColumnVector3.h>
50 #include <models/FGAuxiliary.h>
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62 #define ID_TANK "$Id$"
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74 /** Models a fuel tank.
76 <h3>Fuel Temperature:</h3>
78 Fuel temperature is calculated using the following assumptions:
80 Fuel temperature will only be calculated for tanks which have an initial fuel
81 temperature specified in the configuration file.
83 The surface area of the tank is estimated from the capacity in pounds. It
84 is assumed that the tank is a wing tank with dimensions h by 4h by 10h. The
85 volume of the tank is then 40(h)(h)(h). The area of the upper or lower
86 surface is then 40(h)(h). The volume is also equal to the capacity divided
87 by 49.368 lbs/cu-ft, for jet fuel. The surface area of one side can then be
88 derived from the tank's capacity.
90 The heat capacity of jet fuel is assumed to be 900 Joules/lbm/K, and the
91 heat transfer factor of the tank is 1.115 Watts/sq-ft/K.
95 Fuel dumping is handled by the FGPropulsion class. A standpipe can be defined
96 here for each tank which sets the level of contents (in pounds) which is not dumpable.
97 Default standpipe level is zero, making all contents dumpable.
99 <h3>Fuel Transfer:</h3>
101 Fuel transfer is handled by the FGPropulsion class, however the contents of tanks
102 may be manipulated directly using the SetContents() function here, or via the property
103 tree at <tt>propulsion/tank[i]/contents-lbs</tt>, where i is the tank number (Tanks
104 are automatically numbered, starting at zero, in the order in which they are read in
105 the aircraft configuration file). The latter method allows one to use a system of FCS
106 components to control tank contents.
108 <h3>Configuration File Format:</h3>
111 <tank type="{FUEL | OXIDIZER}">
112 <location unit="{FT | M | IN}">
117 <drain_location unit="{FT | M | IN}">
122 <radius unit="{FT | M}"> {number} </radius>
123 <capacity unit="{LBS | KG}"> {number} </capacity>
124 <contents unit="{LBS | KG}"> {number} </contents>
125 <temperature> {number} </temperature> <!-- must be degrees fahrenheit -->
126 <standpipe unit="{LBS | KG"}> {number} </standpipe>
130 <h3>Definition of the tank configuration file parameters:</h3>
132 - \b type - One of FUEL or OXIDIZER. This is required.
133 - \b radius - Equivalent radius of tank for modeling slosh, defaults to inches.
134 - \b capacity - Capacity, defaults to pounds.
135 - \b contents - Initial contents, defaults to pounds.
136 - \b temperature - Initial temperature, defaults to degrees Fahrenheit.
137 - \b standpipe - Minimum contents to which tank can dump, defaults to pounds.
140 - \b x - Location of tank on aircraft's x-axis, defaults to inches.
141 - \b y - Location of tank on aircraft's y-axis, defaults to inches.
142 - \b z - Location of tank on aircraft's z-axis, defaults to inches.
145 - \b x - Location of tank drain on aircraft's x-axis, defaults to inches.
146 - \b y - Location of tank drain on aircraft's y-axis, defaults to inches.
147 - \b z - Location of tank drain on aircraft's z-axis, defaults to inches.
149 <h3>Default values of the tank configuration file parameters:</h3>
151 - \b type - ttUNKNOWN (causes a load error in the propulsion configuration)
152 - \b location, \b drain_location - both optional, but a warning message will
153 be printed to the console if the location is not given
154 - \b x - 0.0 (both full and drained CG locations)
155 - \b y - 0.0 (both full and drained CG locations)
156 - \b z - 0.0 (both full and drained CG locations)
160 - \b temperature - -9999.0
163 @author Jon Berndt, Dave Culp
164 @see Akbar, Raza et al. "A Simple Analysis of Fuel Addition to the CWT of
165 747", California Institute of Technology, 1998,
166 http://www.galcit.caltech.edu/EDL/projects/JetA/reports/lumped.pdf
169 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
171 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
173 class FGTank : public FGJSBBase
177 The constructor reads in the defining parameters from a configuration file.
178 @param exec a pointer to the base FGFDMExec instance.
179 @param el a pointer to the Tank element.
180 @param tank_number the tank number (zero based).
182 FGTank(FGFDMExec* exec, Element* el, int tank_number);
186 /** Removes fuel from the tank.
187 This function removes fuel from a tank. If the tank empties, it is
189 @param used the amount of fuel used in lbs.
190 @return the remaining contents of the tank in lbs.
192 double Drain(double used);
194 /** Performs local, tanks-specific calculations, such as fuel temperature.
195 This function calculates the temperature of the fuel in the tank.
196 @param dt the time step for this model.
197 @return the current temperature in degrees Celsius.
199 double Calculate(double dt);
201 /** Retrieves the type of tank: Fuel or Oxidizer.
202 @return the tank type, 0 for undefined, 1 for fuel, and 2 for oxidizer.
204 int GetType(void) {return Type;}
206 /** Resets the tank parameters to the initial conditions */
207 void ResetToIC(void);
209 /** If the tank is supplying fuel, this function returns true.
210 @return true if this tank is feeding an engine.*/
211 bool GetSelected(void) {return Selected;}
213 /** Gets the tank fill level.
214 @return the fill level in percent, from 0 to 100.*/
215 double GetPctFull(void) {return PctFull;}
217 /** Gets the capacity of the tank.
218 @return the capacity of the tank in pounds. */
219 double GetCapacity(void) {return Capacity;}
221 /** Gets the contents of the tank.
222 @return the contents of the tank in pounds. */
223 double GetContents(void) const {return Contents;}
225 /** Gets the temperature of the fuel.
226 The temperature of the fuel is calculated if an initial tempearture is
227 given in the configuration file.
228 @return the temperature of the fuel in degrees C IF an initial temperature
229 is given, otherwise 0.0 C is returned. */
230 double GetTemperature_degC(void) {return Temperature;}
232 /** Gets the temperature of the fuel.
233 The temperature of the fuel is calculated if an initial tempearture is
234 given in the configuration file.
235 @return the temperature of the fuel in degrees F IF an initial temperature
236 is given, otherwise 32 degrees F is returned. */
237 double GetTemperature(void) {return CelsiusToFahrenheit(Temperature);}
239 double GetStandpipe(void) {return Standpipe;}
241 const FGColumnVector3 GetXYZ(void);
242 const double GetXYZ(int idx);
244 double Fill(double amount);
245 void SetContents(double amount);
246 void SetTemperature(double temp) { Temperature = temp; }
247 void SetStandpipe(double amount) { Standpipe = amount; }
249 enum TankType {ttUNKNOWN, ttFUEL, ttOXIDIZER};
255 FGColumnVector3 vXYZ;
256 FGColumnVector3 vXYZ_drain;
260 double Contents, InitialContents;
262 double Temperature, InitialTemperature;
263 double Standpipe, InitialStandpipe;
265 FGAuxiliary* Auxiliary;
266 FGPropertyManager* PropertyManager;
267 void Debug(int from);
270 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%