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REQUIRE "ivpsystem.a4l"; |
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REQUIRE "atoms.a4l"; |
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REQUIRE "johnpye/thermo_types.a4c"; |
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IMPORT "freesteam"; |
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IMPORT "dsg"; |
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|
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(* |
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This model requires the 'freesteam' library be installed on your system. |
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You must compile it with the 'ASCEND_CONFIG=`which ascend-config`' flag |
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to ensure that the required external library is installed where ASCEND |
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can find it. Alternatively, you can specify the location by adding to the |
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ASCENDLIBRARY path variable. See http://freesteam.sf.net/ |
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|
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This model also requires the 'dsg' library for Direct Steam Generation |
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calculations, available on request from http://pye.dyndns.org/ |
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|
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For example (assuming you already have the source code for the above): |
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export $ASCENDLIBRARY=$HOME/src/ascend/models |
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cd $HOME/src/freesteam |
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scons -j2 ascend |
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export ASCENDLIBRARY=$HOME/src/freesteam/ascend:$ASCENDLIBRARY |
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cd $HOME/src/dsg-transient |
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scons -j2 ascend |
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export ASCENDLIBRARY=$HOME/src/dsg-transient/ascend:$ASCENDLIBRARY |
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export PATH=$PATH:$HOME/src/ascend/pygtk |
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ascdev johnpye/dsg.a4c |
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*) |
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|
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MODEL dsg; |
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(* temporal derivatives *) |
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drho_dt IS_A density_rate; |
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dmdot_dt IS_A mass_rate_rate; |
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drhou_dt IS_A power_per_volume; |
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dTw_dt IS_A temperature_rate; |
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|
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(* spatial derivatives *) |
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dmdot_dz IS_A mass_rate_per_length; |
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dmdoth_dz IS_A solver_var; |
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dekdot_dz IS_A solver_var; |
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dp_dz IS_A pressure_per_length; |
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drhovel2_dz IS_A pressure_per_length; |
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|
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(* wall properties *) |
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rhow IS_A mass_density; |
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D2 IS_A distance; |
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cw IS_A specific_heat_capacity; |
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Aw IS_A area; |
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hw IS_A heat_transfer_coefficient; |
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|
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Aw = 1{PI}*(D2^2 - D^2)/4; |
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|
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(* conservation equations *) |
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massbal: drho_dt = -1/A * dmdot_dz; |
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mombal: 1/A * dmdot_dt = -dp_dz - f/D/2*rho*vel^2 - drhovel2_dz; |
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enerbal: drhou_dt = 1/A * ( qdott - dmdoth_dz + mdot * dekdot_dz ); |
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pipebal: dTw_dt = 1/rhow/Aw/cw * (qdots - qdotl - qdott); |
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|
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rho IS_A mass_density; |
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mdot IS_A mass_rate; |
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p IS_A pressure; |
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f IS_A positive_factor; (* pipe friction factor *) |
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f_LO IS_A positive_factor; (* liquid-only friction factor *) |
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u IS_A specific_energy; |
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h IS_A specific_enthalpy; |
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vel IS_A speed; |
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qdott, qdotl,qdots IS_A power_per_length; |
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mu IS_A viscosity; |
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v IS_A specific_volume; |
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T, Tw, Tamb IS_A temperature; |
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ekdot IS_A specific_power; |
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|
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rhou IS_A energy_per_volume; |
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rhou = rho * u; |
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|
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rho * v = 1; |
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ekdot = 0.5 * rho * vel^2; |
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|
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thermo_props: iapws97_uvTxmu_ph( |
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p,h : INPUT; |
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u,v,T,x,mu : OUTPUT |
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); |
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|
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vel = rho*mdot/A; |
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|
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Re IS_A positive_factor; |
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Re_rel: Re = rho*vel*D/mu; |
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eps_on_D IS_A factor; |
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eps_on_D_rel: eps_on_D = eps/D; |
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|
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D IS_A distance; |
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eps IS_A distance; |
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A IS_A area; |
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A = 1{PI}* D^2 / 4; |
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|
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friction: dsg_friction_factor( |
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Re, eps_on_D : INPUT; |
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f_LO : OUTPUT |
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); |
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|
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phi2 IS_A positive_factor; |
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x IS_A fraction; |
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twophmult: dsg_phi2_martinelli_nelson( |
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p,x : INPUT; |
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phi2 : OUTPUT |
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); |
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(* TODO: compute LIQUID ONLY reynolds number when in the two-phase region... |
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that's a bit tricky and needs conditional modelling, so maybe try putting |
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it in the external code. *) |
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|
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f = f_LO*rho2; |
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|
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cavity_losses: dsg_ext_heat_loss( |
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Tw,Tamb,D2,hw : INPUT; |
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qdotl : OUTPUT |
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); |
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|
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mdoth IS_A energy_rate; |
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mdoth = mdot * h; |
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|
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rhovel2 IS_A solver_var; |
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rhovel2 = rho * vel^2; |
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|
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(* internal heat transfer *) |
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|
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h1 IS_A heat_transfer_coefficient; |
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|
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qdott = h1 * 1{PI} * D * (Tw - T); |
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|
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twophconv: dsg_conv_coeff_two_phase( |
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p, h, mdot, D, f : INPUT; |
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h1 : OUTPUT |
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); |
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|
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t IS_A time; |
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|
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METHODS |
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|
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METHOD specify; |
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RUN fix_design; |
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RUN fix_states; |
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RUN fix_spatials; |
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RUN ode_init; |
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END specify; |
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|
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METHOD fix_states; |
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FIX Tw, p, h, mdot; |
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END fix_states; |
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|
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METHOD fix_design; |
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(* design parameters, geometry, materials of construction *) |
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FIX rhow,D2,cw,hw; |
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FIX D, eps; |
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FIX qdots; |
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FIX Tamb; |
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END fix_design; |
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|
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METHOD fix_spatials; |
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(* for use when tinkering about with a single node only *) |
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FIX dmdot_dz, dmdoth_dz, dekdot_dz, dp_dz, drhovel2_dz; |
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END fix_spatials; |
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|
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METHOD fix_temporals; |
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(* for steady-state solution *) |
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FIX drho_dt; |
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FIX dmdot_dt; |
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FIX drhou_dt; |
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FIX dTw_dt; |
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END fix_temporals; |
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|
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METHOD values; |
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(* design parameters *) |
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D := 60 {mm}; |
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D2 := 70 {mm}; |
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eps := 0.05 {mm}; |
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rhow := 7.8 {g/cm^3}; |
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cw := 0.47 {J/g/K}; |
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hw := 10 {W/m^2/K}; |
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Tamb := 300 {K}; |
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|
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(* states *) |
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Tw := 600 {K}; |
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p := 10 {bar}; |
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h := 4000 {kJ/kg}; |
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mdot := 0.001 {kg/s}; |
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|
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(* spatial derivs *) |
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dp_dz := -200 {Pa/m}; |
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dmdot_dz := 0 {kg/s/m}; |
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drhovel2_dz := (0 {kg/m^3}) * (0 {m/s})^2 / (1 {m}); |
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dekdot_dz := 0 {W/m}; |
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dmdoth_dz := dmdot_dz * 0 {kJ/kg}; |
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|
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(* derivative variables *) |
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drho_dt := 0 {kg/m^3/s}; |
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dmdot_dt := 0 {kg/s/s}; |
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drhou_dt := 0 {kg/m^3*kJ/kg/s}; |
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dTw_dt := 0 {K/s}; |
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|
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drhou_dt.nominal := rhou.nominal / 60 {s}; |
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|
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v := 0.2 {m^3/kg}; |
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|
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(* bounds *) |
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f.lower_bound := 0.008; |
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v.lower_bound := 0.00999 {m^3/kg}; |
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v.upper_bound := 1/(0.0202 {kg/m^3}); |
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u.lower_bound := 0 {kJ/kg}; |
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u.upper_bound := 3663 {kJ/kg}; |
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|
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(* starting guesses *) |
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Re := 10000; |
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END values; |
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|
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METHOD ode_init; |
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t.ode_type := -1; |
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t := 0 {s}; |
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|
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rho.ode_id := 1; drho_dt.ode_id := 1; |
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rho.ode_type := 1; drho_dt.ode_type := 2; |
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|
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mdot.ode_id := 2; dmdot_dt.ode_id := 2; |
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mdot.ode_type := 1; dmdot_dt.ode_type := 2; |
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|
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rhou.ode_id := 3; drhou_dt.ode_id := 3; |
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rhou.ode_type := 1; drhou_dt.ode_type := 2; |
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|
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Tw.ode_id := 4; dTw_dt.ode_id := 4; |
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Tw.ode_type := 1; dTw_dt.ode_type := 2; |
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|
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rho.obs_id := 1; |
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mdot.obs_id := 2; |
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rhou.obs_id := 3; |
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Tw.obs_id := 4; |
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|
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END ode_init; |
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|
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METHOD on_load; |
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RUN reset; |
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RUN values; |
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END on_load; |
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|
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END dsg; |
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