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Thu Aug 30 02:29:50 2007 UTC (12 years, 11 months ago) by jpye
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1 (* Air properties calculator for ASCEND modelling environment
2 Copyright (C) John Pye 2007
3
4 This program is free software; you can redistribute it
5 and/or modify it under the terms of the GNU General Public
6 License as published by the Free Software Foundation; either
7 version 2 of the License, or (at your option) any later
8 version.
9
10 This program is distributed in the hope that it will be
11 useful, but WITHOUT ANY WARRANTY; without even the implied
12 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
13 PURPOSE. See the GNU General Public License for more
14 details.
15
16 You should have received a copy of the GNU General Public
17 License along with this program; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330,
19 Boston, MA 02111-1307 USA
20 *)
21 REQUIRE "atoms.a4l";
22 REQUIRE "johnpye/thermo_types.a4c";
23
24 (*
25 The air property correlations here are taken from the paper by
26 George A. Adebiyi, 'Formulations for the Thermodynamic Properties of
27 Pure Substance', J Energy Res Tech., 2005. doi:10.1115/1.1794695
28
29 Currently, this model just allows the enthalpy of air to be calculated
30 given the pressure and temperature. Other correlations are implemented
31 in the Adebiyi paper, but they haven't been coded here yet.
32 *)
33 MODEL airprops;
34 p IS_A pressure;
35 T IS_A temperature;
36
37 p_c IS_A pressure_constant;
38 p_c :== 37.7 {bar};
39
40 T_c IS_A temperature_constant;
41 T_c :== 132.6 {K};
42
43 p_r IS_A factor;
44 p_r = p / p_c;
45
46 T_r IS_A factor;
47 T_r = T / T_c;
48
49 a[0..6] IS_A real_constant;
50 a[0] :== 1.685175;
51 a[1] :== 2.283617;
52 a[2] :== -0.49965;
53 a[3] :== 0.108826;
54 a[4] :== -0.012765;
55 a[5] :== 7.471154e-4;
56 a[6] :== -1.732085e-5;
57
58 b_1, b_2, b_3 IS_A real_constant;
59 b_1 :== 0.1629;
60 b_2 :== -0.338964;
61 b_3 :== -0.143369;
62
63 h_r0 IS_A real_constant;
64 h_r0 :== -9.08244;
65
66 M IS_A molar_weight_constant;
67 M :== 28.97 {kg/kmol};
68
69 h IS_A specific_enthalpy;
70 h_r IS_A factor;
71 h_r = h * M / 1{GAS_C} / T_c;
72
73 h_r = SUM[ a[k]/(k+0.5)*T_r^(k+0.5) | k IN [0..6]] + h_r0
74 + ( b_1 + 2.6*b_2 / T_r^1.6 + 1.6 * b_3 / T_r^0.6 ) * p_r;
75
76 METHODS
77 METHOD on_load;
78 FIX p, T;
79 p := 1 {bar};
80 T := 300 {K};
81 END on_load;
82 END airprops;
83

john.pye@anu.edu.au
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