NESC0809 TVENT1P.

1. NAME OR DESIGNATION OF PROGRAM:  TVENT1P.

3. DESCRIPTION OF PROBLEM OR FUNCTION

TVENT1P predicts flows and pressures in a ventilation system or other air pathway caused by pressure transients, such as a tornado. For an analytical model to simulate an actual system, it must have (1) the same arrangement of  components in a network of flow paths; (2) the same friction characteristics; (3) the same boundary pressures; (4) the same capacitance; and (5) the same forces that drive the air. A specific  set of components used for constructing the analytical model includes filters, dampers, ducts, blowers, rooms, or volume connected at nodal points to form networks. The effects of a number  of similar components can be lumped into a single one.
TVENT1P contains a material transport algorithm and features for turning blowers off and on, changing blower speeds, changing the resistance of dampers and filters, and providing a filter model to handle very high flows. These features make it possible to depict a  sequence of events during a single run. Component properties are varied using time functions. The filter model is not used by the code unless it is specified by the user. The basic results of a TVENT1P solution are flows in branches and pressures at nodes. A postprocessor program, PLTTEX, is included to produce the plots specified in the TVENT1P input. PLTTEX uses the proprietary CA-DISSPLA graphics software (see http://www.gaeinc.com).

4. METHOD OF SOLUTION

The continuity equation is satisfied at each node in the flow network with the dependent variable (pressure) solved simultaneously by point-wise (local) relaxation techniques. The flows are determined from the calculated pressures with experimental or classical flow descriptions. The boundary conditions are specified as stated but are arbitrary functions of time. The material transport algorithm is based on a simple convection model.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
   500 branches
   400 nodes
    60 rooms
    50 boundary nodes
    25 plot frames with 4 plots per frame
    20 resistance functions
    20 removed branches
    20 removed nodes
    20 points per blower curve
    17 blower curves
    10 filter models
    10 blower speed functions
     5 material functions
     5 control dampers
Assumptions include one-dimensional, isothermal flow, lumped parameters (neglecting spatial distribution of components), and incompressible flow with fluid storage at nodes. TVENT1P does not include inertia or shock.

6. TYPICAL RUNNING TIME

Running time depends on problem complexity, as well as the number of branches or nodes. NESC executed the sample problem in 5 CP seconds on a CDC CYBER170/875 and in 1 CPU minute on an IBM4331.

7. UNUSUAL FEATURES OF THE PROGRAM

TVENT1P is designed to be portable and is highly user-oriented for architect-engineers and heating, ventilation, and air conditioning (HVAC) designers. The program is self-contained and does not require nonstandard system utilities.  Line printer plots are generated.

8. RELATED AND AUXILIARY PROGRAMS

The original IBM360 version of TVENT was prepared by K.H. Duerre, R.W. Andrae, and W.S. Gregory of  Los Alamos National Laboratory.

10. REFERENCES

- TVENT1P, NESC No. 809.7600, TVENT1P CDC Version Tape Description,
  National Energy Software Center Note 87-106, September 30, 1987.
- TVENT1P, NESC No. 809.4331, TVENT1P IBM Version Tape Description,
  National Energy Software Center Note 87-107, September 30, 1987.

- K.H. Duerre, R.W. Andrae and W.S. Greory:
  TVENT - A Computer Program for Analysis of Tornado-Induced
  Transients in Ventilation Systems
  LA-7397-M Rev. (April 1979).
- K.H. Duerre, R.W. Andrae and W.S. Greory:
  TVENT - A Computer Program for Analysis of Tornado-Induced
  Transients in Ventilation Systems
  LA-7397-M Rev. (April 1979).

11. MACHINE REQUIREMENTS

The CDC7600 version requires 114,000 (octal)  words of memory; the IBM4331 requires 540 Kbytes.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  NOS 2.2, LTSS, and SCOPE (CDC7600), VM/CMS (IBM4331).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

  Only
one set of input data may be processed per execution. The program is structured as a one-level overlay to permit use on medium-size computers and to provide for program expansion. The auxiliary program, PLLTEX, is written in FORTRAN66. The CDC7600 version of PLLTEX was not tested by NESC.

15. NAME AND ESTABLISHMENT OF AUTHORS

   7600     R.W. Andrae, P.K. Tang, and W.S. Gregory
            Los Alamos Scientific Laboratory
            P. O. Box 1663
            Los Alamos, New Mexico 87545

   4331     L.R. Eyberger
            National Energy Software Center
            Argonne National Laboratory

File name	File description	Records
NESC0809_01.001	INFORMATION	18
NESC0809_01.002	SOURCE (F4,EBCDIC)	3280
NESC0809_01.003	SIMPLE VENTILATION SYSTEM (S.P.1)	35
NESC0809_01.004	TYP. ARCHITECT-ENGINEERING FORMAT (S.P.2)	42
NESC0809_01.005	S.P.3 (TO BE RESTARTED)	42
NESC0809_01.006	S.P.4 (RESTART JOB)	44
NESC0809_01.007	SERIES-PARALLEL NETWORK (S.P.5)	64
NESC0809_01.008	SIMPLIFIED SERIES-PARALLEL NETWORK (S.P.6)	46
NESC0809_01.009	SIMPLIFIED PARALLEL NETWORK (S.P.7)	46
NESC0809_01.010	JCL AT ANL	73
NESC0809_01.011	JCL AT NEA	19
NESC0809_01.012	PRINTED OUTPUT OF S.P.1	410
NESC0809_01.013	PRINTED OUTPUT OF S.P.2	520
NESC0809_01.014	PRINTED OUTPUT OF S.P.3	441
NESC0809_01.015	PRINTED OUTPUT OF S.P.4	432
NESC0809_01.016	PRINTED OUTPUT OF S.P.5	200
NESC0809_01.017	PRINTED OUTPUT OF S.P.6	510
NESC0809_01.018	PRINTED OUTPUT OF S.P.7	157

File name	File description	Records
NESC0809_02.001	INFORMATION	6
NESC0809_02.002	SOURCE (F4,EBCDIC)	3288
NESC0809_02.003	INPUT DATA FOR S.P.1	35
NESC0809_02.004	INPUT DATA FOR S.P.2	42
NESC0809_02.005	INPUT DATA FOR S.P.3	42
NESC0809_02.006	INPUT DATA FOR S.P.4	44
NESC0809_02.007	INPUT DATA FOR S.P.5	64
NESC0809_02.008	INPUT DATA FOR S.P.6	46
NESC0809_02.009	INPUT DATA FOR S.P.7	64
NESC0809_02.010	INPUT DATA FOR S.P.8	46
NESC0809_02.011	PRINTED OUTPUT OF S.P.1	410
NESC0809_02.012	PRINTED OUTPUT OF S.P.2	520
NESC0809_02.013	PRINTED OUTPUT OF S.P.3	441
NESC0809_02.014	PRINTED OUTPUT OF S.P.4	432
NESC0809_02.015	PRINTED OUTPUT OF S.P.5	591
NESC0809_02.016	PRINTED OUTPUT OF S.P.6	510
NESC0809_02.017	PRINTED OUTPUT OF S.P.7	585
NESC0809_02.018	PRINTED OUTPUT OF S.P.8	509