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REQUIRE "johnpye/thermo_types.a4c"; |
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|
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MODEL iapws_sat_pressure; |
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|
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p IS_A pressure; |
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T IS_A temperature; |
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pc IS_A pressure_constant; |
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Tc IS_A temperature_constant; |
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|
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Tc :== 647.096 {K}; |
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pc :== 22.064 {MPa}; |
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|
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tau IS_A factor; |
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tau_eq: tau = 1 - (T/Tc); |
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|
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sat_pressure_curve: ln(p/pc) = (Tc/T)*( |
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a[1]*tau + a[2]*tau^1.5 + a[3]*tau^3 + a[4]*tau^3.5 + a[5]*tau^4 + a[6]*tau^7.5 |
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); |
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|
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a[1..6] IS_A real_constant; |
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a[1] :== -7.85951783; |
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a[2] :== 1.84408259; |
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a[3] :== -11.7866497; |
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a[4] :== 22.6807411; |
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a[5] :== -15.9618719; |
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a[6] :== 1.80122502; |
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|
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METHODS |
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METHOD default_self; |
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RUN reset; RUN values; |
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END default_self; |
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METHOD specify; |
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FIX T; |
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END specify; |
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METHOD values; |
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T := 373.1243 {K}; |
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END values; |
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METHOD self_test; |
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ASSERT abs(p - 101.325 {kPa}) < 1 {Pa}; |
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END self_test; |
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|
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END iapws_sat_pressure; |
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|
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MODEL iapws_sat_density; |
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|
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rhof IS_A mass_density; |
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rhog IS_A mass_density; |
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rhoc IS_A mass_density_constant; |
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Tc IS_A temperature_constant; |
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T IS_A temperature; |
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|
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rhoc :== 322 {kg/m^3}; |
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Tc :== 647.096 {K}; |
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|
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tau IS_A factor; |
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|
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tau = 1 - T/Tc; |
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|
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rhof / rhoc = 1 + b[1]*tau^(1/3) + b[2]*tau^(2/3) + b[3]*tau^(5/3) + b[4]*tau^(16/3) + b[5] * tau^(43/3) + b[6]*tau^(110/3); |
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|
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rhog / rhoc = exp( c[1]*tau^(2/6) + c[2] * tau^(4/6) +c[3]*tau^(8/6) + c[4] *tau^(18/6) + c[5]*tau^(37/6) + c[6]*tau^(71/6) ); |
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|
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b[1..6] IS_A real_constant; |
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b[1] :== 1.99274064; |
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b[2] :== 1.09965342; |
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b[3] :== -0.510839303; |
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b[4] :== -1.75493479; |
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b[5] :== -45.5170352; |
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b[6] :== -6.74694450e5; |
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|
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c[1..6] IS_A real_constant; |
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c[1] :== -2.03150240; |
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c[2] :== -2.68302940; |
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c[3] :== -5.38626492; |
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c[4] :== -17.2991605; |
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c[5] :== -44.7586581; |
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c[6] :== -63.9201063; |
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|
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METHODS |
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|
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METHOD default_self; |
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RUN test_1; |
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END default_self; |
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|
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METHOD specify; |
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FIX T; |
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END specify; |
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|
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METHOD values; |
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T := 273.16 {K}; |
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END values; |
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|
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(* the following methods implement the reference data points from the IAPWS supsat.pdf release. *) |
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|
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METHOD test_1; |
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RUN ClearAll; |
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RUN specify; |
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RUN values; |
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END test_1; |
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|
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METHOD test_2; |
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RUN ClearAll; |
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RUN specify; |
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T := 373.1243 {K}; |
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END test_2; |
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|
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METHOD test_3; |
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RUN ClearAll; |
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RUN specify; |
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T := 647.096 {K}; |
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END test_3; |
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|
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END iapws_sat_density; |
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