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*Tue Jan 16 11:33:52 2007 UTC*
(17 years, 5 months ago)
by *johnpye*

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More tidying up of old models. Will add roots_of_poly to the list.

1 | REQUIRE "atoms.a4l"; |

2 | REQUIRE "johnpye/thermo_types.a4c"; |

3 | |

4 | (* |

5 | Solution the Horwitz A, "The Case of the Collapsing Can", Chemical |

6 | Engineering Progress, Jun 1997, pp.61-65. |

7 | |

8 | "A fixed-volume vessel contains one pound of saturated water vapor at 14.7 |

9 | psia. One pound of water at 70 deg F and 14.7 psia is introduced |

10 | into the vessel. Assuming the entire process is adiabatic (no heat loss to |

11 | the surroundings), find the amount of liquid and vapor present in the |

12 | vessel, and the temperature and pressure in the vessel." |

13 | |

14 | Model file created by John Pye, Jan 2007. |

15 | *) |

16 | MODEL collapsingcan; |

17 | (* Although these variables are dimensional, the way that the correlation |

18 | equations in the paper are writtem make it simplest to express this model |

19 | in non-dimensional terms *) |

20 | x IS_A solver_var; (* lb *) |

21 | y IS_A solver_var; (* lb *) |

22 | sv IS_A solver_var; (* ft^3 *) |

23 | ul IS_A solver_var; (* Btu/lb *) |

24 | uv IS_A solver_var; (* Btu/lb *) |

25 | p IS_A solver_var; (* psia *) |

26 | T IS_A solver_var; (* deg F *) |

27 | |

28 | x * 0.016 + y * sv = 26.8; (* final volume = initial volume *) |

29 | x + y = 2.0; (* mass balance *) |

30 | |

31 | (* The following curves were based on regression-fits to Keenen and Keyes |

32 | steam tables performed by the author specifically for the purpose of |

33 | solving this problem *) |

34 | 38.2 + 1077 = ul * x + uv * y; (* internal energy balance *) |

35 | sv = 90.6607 -7.109 * p + 0.18803 * p^2; (* sv as fn of pressure *) |

36 | ul = 101.4992 + 7.2929 * p - 0.13267 * p^2; (* ul as fn of pressure *) |

37 | uv = 1060.0 + 1.25965 * p - 0.00535 * p^2; (* uv as fn of pressure *) |

38 | T = 133.65 + 7.2905 * p - 0.13339 * p^2; (* temperature as fn of pressure *) |

39 | |

40 | METHODS |

41 | |

42 | METHOD on_load; |

43 | RUN ClearAll; |

44 | END on_load; |

45 | |

46 | METHOD self_test; |

47 | (* The following results use the solution values as published in the |

48 | original paper. Note that this model is tested regularly as part of the |

49 | ASCEND automated test suite, 'test.py'. *) |

50 | ASSERT abs(x - 1.1453809) < 0.0000002; |

51 | ASSERT abs(y - 0.85461909) < 0.00000002; |

52 | ASSERT abs(sv- 31.337556) < 0.000002; |

53 | ASSERT abs(ul- 171.66791) < 0.00002; |

54 | ASSERT abs(uv- 1074.8354) < 0.0002; |

55 | ASSERT abs(p - 12.434039) < 0.000002; |

56 | ASSERT abs(T - 203.67756) < 0.00002; |

57 | END self_test; |

58 | |

59 | END collapsingcan; |

60 | (* :ex: set ts=4: *) |

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