software for solving ventilation networks

DEVELOPED BY

M.VENKAT RAMANA RAO

M.V.RAMANA RAO*

VENSNET
(SOFTWARE FOR VENTILATION NETWORKS)

ABSTRACT :

With the rapid advance in the semiconductor electronics the old stories of
computing and huge size computers are replaced with the highly efficient and fast
processing mini and micro computers at a low cost. From 1960’s onwards digital
computers have been finding increasing application in planning, designing, operating
and controlling industrial systems. A computer’s great power lies in its ability to
acquire, store, recall, manipulate and modify enormous volumes of data with in a
fraction of seconds.

The major advantages of computer-oriented approach are
i). Pool proof decision making.
ii). Reduction in costs.
iii). Increased timeliness of results and efficiency in operation
iv). Increased scientific reasoning.
v). Forced quantitative thinking.

Presently, every field or industry is using the computers enormously at every
stage. Mining or mineral Industry is not an exception and using computers for
planning, engineering and control of mines. In particular, the application of
computers in solving problems of planning and design, involving the mine
atmospheric environment is finding most importance. In earlier days, the Ventilation
system of a mine was planned based on the experience and with the use of some
thumb rules. Solving of a complex ventilation network of a mine cannot be done
manually and usage of a computer is must.

Prof. Hardy-Cross (Cross, 1936; Scott and Hinsley, 1951) has developed an
iterative method using computer for solving the complex ventilation networks. Based
on the same algorithm, this software program called VENSNET has been developed.
This software facilitates the easy drawing of the network with the help of a mouse.
Modification of the network and its different parameters can be done with the
operation of different menus. Different alternatives can be tried easily and compared
for better solution. The main advantage of this software program is in its being user
friendly.

1.0 INTRODUCTION:

1.1 ABOUT VENSNET :

VENSNET (Software for Ventilation Networks) has been developed for
designing underground mine ventilation systems keeping in view the present

* GME, No.5 Incline, Kothagudem
The Singareni Collieries Company Limited, Kothagudem – 507 119,
Andhra Pradesh, INDIA.

requirement and the future needs of Indian mining industry. This software program
handles large and complicated mine ventilation networks and solves them in most
efficient manner. The important features of this software are
1. Drawing the network with the help of a computer mouse and of its user-
friendly nature.
2. The use of a new simplified algorithm for solving the complex mine
ventilation network.
3. Analyzing the different alternative schemes of ventilation in a single run of the
program.
4. Graphical representation of total network on the screen as well as hard copy
on printer.
5. Post processing of the output and drawing mine characteristics, fan
characteristics and operating point, fixed quantity branches, computation of
fan characteristics.
6. Handling of data using interactive input output with menu selections and
excellent drawing facility of the network with zooming option.

INTRODUCTION TO VENSNET (SOFTWARE FOR VENTILATION NETWORKS)

1.2 BENEFITS:

The major advantages that we are going to get with the usage of this software
program are
1. For a mine involving complex ventilation circuit
a. Multi seam and multi section workings can be maintained by proper
ventilation with out much pressure differences.
b. If there is any problem in any gallery due to spontaneous heating or
fire and explosion then the readjustment of quantities so as to reduce
the quantity in that particular branch can be easily studied and effect of
this reduction in quantity in one branch on other branches can be
known in advance.
c. The high resistance branches are identified and with the change in
resistance of a particular branch effect on total quantity of the mine can

be predicted easily and to increase the quantity to a maximum level,
which branch resistance is to be reduced can be easily known.
d. Complexity involved in planning the ventilation of a mine having
workings in different seams and in different sections of a seam is
reduced and can be easily planned at mine level by a ventilation officer
with some little practice and knowledge about the usage of this
software.
e. Effect of day-to-day alterations on total ventilation of the mine can be
easily predicted by the ventilation officer or manager to make quicker
and efficient decisions.
2. Analysis of Ventilation network, mine characteristics and fan characteristics to
decide blade angle, operation, etc. can be effectively done.
3. With addition or deletion of part of the mine working in future, effect on the
existing ventilation circuit and the need for a booster fan or regulator can be
known in advance and an alternative measure can be think-off or can make
preparations for getting the permission of a booster fan installation in
underground under the Regulation 133 of CMR, 1957.
4. With the change in blade angle of the fan effect on total quantity can be
known and simulation study can be made easily by putting different fans in
place of existing fan and thereby a proper fan is selected, which will operate at
maximum efficiency with optimum power consumption, which will not only
saves the energy but also reduces the power cost.

2.0 DESCRIPTION OF THE SOFTWARE:

The VENSNET software program is the integration of two different models
and the functions of each of these model s are as given below:

1. VENSNET.EXE :

This is the main program controlling various operations and it provides the
facility for drawing the ventilation network in pictorial form with the help
of mouse, saving and loading of network. It also provides the facility of
zooming and several other user friendly features. The important thing that
is provided in this software is the auto saving. The drawn network with all
input values is saved automatically in a file, named ‘Autosave.tmp’ for
each mouse click in the area of drawing. The drawn network can be seen
in the form of a table and quantity for any branch can be fixed easily. After
executing the network, fan and mine characteristic curves can be seen
graphically. It also calculates the equivalent orifice of the mine. Addition
of fan in any branch can be done easily either by selecting from the
available fans in the fans library or directly by giving 3 to 8 points on the
fan curve. Results are displayed in the form of a table and can be printed
on a dot matrix printer. The network diagram can also be printed. This
program is written in Pascal-language using graphics.

2. HARDY.TPU:

This is the heart of VENSNET software program, it is not an executable
one, but it aids the above program in calculating the quantities in each

branch with the help of modified algorithm of hardy-cross iterative method
known as Gauss-Seidel method of solving linear equations. This program
is also written in Pascal-language. After solving the network this program
writes results in a compatible format with user file of VENSNET.EXE, so
that the calculations can be represented in the form of a table and can be
taken a hard print.

3.0 MENU STRUCTURE:

This software program uses different menus mentioned below.
1. New 2.Save 3. Open
4. Run 5. Show/Hide 6. Add fan
7. Print 8. Del Jn. 9. Del Br.
10. In Table 11. Arrow Dir. 12. Del Fan
13. Quantity 14. NVP 15. Chg. Jn. No
16. Chg. Resist 17. Graph 18. Zoom
19. Title 20. About
which are explained in detailed form in ANNEXURE-I.

4.0 HARDWARE REQUIREMENTS:

1. Machine Architecture: The software can run only on any IBM compatible
PC based on any processor later to 80x86 microprocessor.

2. Memory Requirement: It requires 720kB of free RAM and minimum of
1MB of disk space for storage of the software and temporary files. It cannot be
run on PC’s without Hard Disk. So for the use of this software program,
please install the software on the hard disk in a separate directory and use it
for solving the network problems.

3. Graphics Adapter: The software requires VGA display for high-resolution
presentation of the network on screen in multiple colours, but it can run on
CGA or EGA monitors also.

4. Printer: Any standard dot matrix printer (e.g. Epson, L&T, TVSE etc).

5. Operating System: It is compatible to MS-DOS as well as to any Windows
operating system.

5.0 INPUT REQUIREMENT:

For solving the ventilation network of any mine the main inputs required are

1. Total Ventilation plan of the mine with pressure drops and quantities at each
junction or the resistance of each roadway calculated from pressure-quantity
survey.
2. All the parameters of the existing fans along with their fan characteristic
curves.
3. The maximum depth of workings.

6.0 APPLICATION TO A SIMPLE NETWORK:

A sample network has been created by using different menu options of this
software. The parameters like maximum iterations (100), the accuracy required (0.01)
and the atmospheric node or basis node (1) are taken by default. The print of the
drawn network is shown in ANNEXURE-II. The input table i.e. the drawn network
in the form of a table is given in ANNEXURE-III. The drawn network is solved and
the results are produced in the form of a table as shown in ANNEXURE-IV. After
calculations are over the equivalent orifice of the mine, the fan characteristic curve
with the mine characteristic and operating point are shown in the form given in
ANNEXURE-V.

7.0 CONCLUSION:

The VENSNET (Software for Ventilation Networks) is a very useful tool for
ventilation network analysis and planning. Because of
1. Interactive input output and various other such features.
2. Analysis of Complex mine ventilation network can be done very
easily by any operating engineer without much training on the
software, computer programming or data file management.
3. The network can be updated on creation of new connections or
sealing off an area and the redistribution of air can be estimated,
which may be of a great help in making important decisions.
4. Decisions like installing a new fan or changing the blade angle of the
existing fan, putting regulator and installing a booster fan can be
taken easily from the analysis results of this program.
5. Power requirement is calculated, thereby reduction in power cost is
possible and a lot of energy is saved improving the productivity of
mine.

8.0 ACKNOWLEDGEMENT:

I am very thankful to Sri.M.S.Venkata Ramayya, Dy.GM, 5Gr. of mines and
Sri.Lolla Sudhakar, Dy.Mgr (Project & Planning) for their full co-operation through
out the development of this software and I am very grateful to the Officials of
Singareni Collieries Company Limited, who directly or indirectly helped me a lot
through their positive criticism. I am also thankful to the Professors of University
College of Engineering, Kakatiya University and especially to Sri.D.Chandra Sekar,
Associate Professor in Mining for their valuable guidance.

9.0 REFERENCES:

1. Hartmen, H.L., 1982, “Mine Ventilation and Air Conditioning”, Second Edition,
John Wiley & Sons, Canada.
2. Deshmukh, D.J., 1998, “Elements of Mining Technology”, 9th Edition, Central
Techno Publications, Nagpur.
3. Newman, W.M. and R.F.Sproull, 1984, “Principles of Interactive Computer
Graphics”, Second Edition, McGraw-Hill, New York.
4. Wisemen, N.E., 1968, “A Note on Compiling Display File from a Data structure”,
Comput.J.

5. Three Rivers Computing Corp., 1978, “Graphic Display Programmer’s Guide”,
Three Rivers Computing Corp., Pittsburgh.
ANNEXURE-I

EXPLANATION OF DIFFERENT MENUS USED IN THE VENSNET
SOFTWARE

1. NEW : By clicking this, the existing network on screen is cleared and a fresh
screen will appear for drawing a new network. If the old network that exists on the
screen is to be used later then it has to be saved, otherwise it will be lost permanently.

2. SAVE : The drawn network can be saved to a file by pressing this, for that we have
to enter the file name. The filename should be of 11 characters, in which the last three
characters indicate the extension. For easy identification of the network files, please
give the extension as ‘.ven’, for example ‘pvknet.ven’ is the filename containing the
network data of Padmavathikhani mine. While saving, it will ask for the Title of the
problem. If nothing is mentioned then it will take the title as ‘PROBLEM’.

3. OPEN : Already saved network file can be opened by this. After entering the
filename it will read the data from that file and draws the network on the screen. The
drawn network is shown below.

4. RUN : By pressing this, the network is solved using the modified Hardy cross
iterative method and the results are stored in a file, named as ‘Outdisp.tmp’ and same
is shown on the screen in the form of a table. The result includes the resistance,
quantity and pressure drop in each branch, pressures at each junction and Natural
ventilation pressure of each branch. It also gives the requirement of a booster fan with
the amount of pressure that has to be developed in any branch and if pressure is more
in any branch then the amount pressure that has to be reduced by putting the regulator
is also mentioned. Finally, it will give the fan operating point with the amount of
pressure that is developed by the fan and the quantity delivered. The output data of an
example problem is given ANNEXURE-IV.

The calculated quantity an pressure loss in each branch with resistances is
shown as below.

The requirement of a regulator of booster fan and the fan operating parameters
are shown as below.

Total power (in kW) required is also calculated, no. of iterations taken to converge is
given along with the final sum of absolute values of correction factors in the last
iteration.

5. SHOW / HIDE : To see the branch numbers on the network diagram it should be
clicked once, to hide again press the same button. The network with branch numbers
shown is looks like in the figure given below.

6. ADD FAN : By pressing this, it will ask for the branch number in which fan is to
be installed. After that, 3 to 8 points on the fan characteristic curve are taken and
entered here or the fan data is automatically taken with the selection of the fan
existing in the fans library. The newly entered points if, necessary can be stored to the
fans library with a suitable description about the fan for future usage.

The available fans in the library can be shown as below.

7. PRINT : The drawn network can be taken a print out on a dot matrix printer. A
print out of the network diagram by using a dot matrix printer is given in
ANNEXURE-II.

8. DEL JN. : It is used for deleting any junction that is present in the network. With
the deletion of a particular junction, the branches that are connected with this junction
are also deleted automatically.

9. DEL BR.: By this any branch in the network can be deleted easily. If a fan exists in
a branch that is to be deleted then, fan must be deleted first then only the branch is
allowed for deletion.

10. IN TABLE : The drawn network is shown in the form of a table with all the
details like branch number, starting and ending junction numbers of each branch,
Resistance, fixed quantities and Natural ventilation pressures of each branch are
shown. Fan data with calculated co-efficients is also displayed. The maximum
number of iterations (fixed to 100), the permissible error (0.01), basis node (node 1)
and the number of fans present is shown as below.

The branches with all the relevant data are shown as below.

The input data of an example problem is given in ANNEXURE-III.

11. ARROW DIR.: By this the direction of the branch can be changed keeping all
other parameters unchanged.

12. DEL FAN : The existing fans in the network can be deleted by this.

13. QUANTITY : With this the quantity in any branch can be fixed, for example the
quantity for a longwall panel is fixed as 20m3/sec. So while calculating the quantities
in each branch during network solving, the quantity in the longwall panel branch is
maintained at 20m3/sec and quantities in all other branches are adjusted if, necessary
it will indicate the need for installation of a booster fan or regulator in a particular
branch.

14. NVP : Natural Ventilation Pressure of any branch can be given by pressing this.

15. CHG. JN. NO. : Junction number can be changed by this.

16. CHG. RESIST. : Resistance of any branch can be altered with this.

17. GRAPH : After solving the drawn network, the mine and fan characteristic
curves are drawn on a graph sheet and the operating point is indicated. It also gives
the equivalent orifice of the mine. This graph can be taken a hard print on paper. The
characteristic curves of mine and fan looks as shown in the below figure.

18. ZOOM : With this any part of the drawn network can be zoomed and seen to a
larger scale. In the zoomed out diagram the resistances of each branch with branch
numbers and junction numbers are shown clearly.

The zooming operation is explained clearly in the following figures.

3.19. TITLE : Pressing this, the title of the currently drawn network can be given.
The default title is ‘Problem’.

3.20. ABOUT: About the software and the details of the developer are displayed by
clicking this. For any suggestions, please mail to venkoos@rediffmail.com

About the program is shown as below.

ANNEXURE-II

A PRINT OUT OF THE SAMPLE NETWORK
BY USING DOT MATRIX PRINTER

ANNEXURE-III

COMPLETE INPUT DATA FOR THE SAMPLE NETWORK
IN THE FORM A TABLE

EXAMPLE PROBLEM

No. of Branches [NB] = 31 Basis node [JDTM] = 1
Maximum No.of Iterations [MIT] = 100 No.of Fans [NFC] = 1
Permissible Error [E] = 0.01

Fan-1 : -> No.of Data Ponts [NDP] = 3
[ Quantity / Pressure ]
1 - 122.00/1000.00
2 - 162.00/600.00
3 - 198.00/200.00

Co-efficients :
C-1= 2289.667897
C-2= -4.963312

BrNo JA JB Resist Quantity FanSt NVP
Ns^2/m^8 m^3/s Pa
1 1 2 0.0073 0.00 0 0.000
2 2 3 0.0553 0.00 0 0.000
3 3 4 0.0066 0.00 0 0.000
4 2 3 0.0042 0.00 0 0.000
5 4 5 0.0017 0.00 0 0.000
6 5 6 0.0016 0.00 0 0.000
7 6 7 0.0055 0.00 0 0.000
8 7 8 0.0056 0.00 0 0.000
9 8 9 0.0048 0.00 0 0.000
10 9 11 0.2720 0.00 0 0.000
11 11 12 0.0124 0.00 0 0.000
12 12 13 0.0080 0.00 0 0.000
13 13 18 0.0061 0.00 0 0.000
14 18 1 0.0058 0.00 1 0.000
15 13 14 0.0028 0.00 0 0.000
16 14 18 0.0046 0.00 0 0.000
17 7 14 3.9849 0.00 0 0.000
18 8 12 3.0000 0.00 0 0.000
19 2 3 1.9500 0.00 0 0.000
20 1 2 0.0034 0.00 0 0.000
21 9 10 4.2830 0.00 0 0.000
22 10 11 0.0511 0.00 0 0.000
23 9 11 8.8716 0.00 0 0.000
24 3 15 0.1219 0.00 0 0.000
25 15 4 0.0450 0.00 0 0.000
26 17 6 0.0050 0.00 0 0.000
27 17 10 13.1861 0.00 0 0.000
28 16 17 0.0315 0.00 0 0.000
29 1 16 0.0073 0.00 0 0.000
30 16 5 0.0050 0.00 0 0.000
31 10 13 0.0128 0.00 0 0.000

No.of Branches [NB] = 31 No.of Junctions [NJ] = 18
Max. Junction No. [MJ] = 18 No.of Fixed Q Branches [LXQ] = 0

No.of Fan Branches [NFN] = 1 No.of Meshes [NM] = 14

ANNEXURE-IV

OUTPUT RESULTS FOR THE SAMPLE NETWORK
IN THE FORM OF A TABLE
EXAMPLE PROBLEM

No.of Branches [NB] = 31 No.of Junctions [NJ] = 18
Max. Junction No. [MJ] = 18 No.of Fixed Q Branches [LXQ] = 0
No.of Fan Branches [NFN] = 1 No.of Meshes [NM] = 14

Branch Jn.A Jn.B R Q HLOSS HJA HJB NVP
Ns^2/m^8 m^3/s Pa Pa Pa Pa
1 1 2 0.0073 22.8 3.8 -0.0 3.8 0.0
2 2 3 0.0553 11.7 7.6 3.8 11.4 0.0
3 3 4 0.0066 46.9 14.5 11.4 25.9 0.0
4 2 3 0.0042 42.5 7.6 3.8 11.4 0.0
5 4 5 0.0017 56.2 5.4 25.9 31.3 0.0
6 5 6 0.0016 91.0 13.3 31.3 44.5 0.0
7 6 7 0.0055 106.6 62.6 44.5 107.1 0.0
8 7 8 0.0056 91.8 47.2 107.1 154.2 0.0
9 8 9 0.0048 75.4 27.3 154.2 181.6 0.0
10 9 11 0.2720 52.7 755.4 181.6 937.0 0.0
11 11 12 0.0124 40.7 20.6 937.0 957.6 0.0
12 12 13 0.0080 57.1 26.1 957.6 983.6 0.0
13 13 18 0.0061 57.6 20.2 983.6 1003.9 0.0
14 18 1 0.0058 115.0 76.7 1003.9 -0.0 0.0
15 13 14 0.0028 42.5 5.1 983.6 988.7 0.0
16 14 18 0.0046 57.4 15.2 988.7 1003.9 0.0
17 7 14 3.9849 14.9 881.6 107.1 988.7 0.0
18 8 12 3.0000 16.4 803.3 154.2 957.6 0.0
19 2 3 1.9500 2.0 7.6 3.8 11.4 0.0
20 1 2 0.0034 33.4 3.8 -0.0 3.8 0.0
21 9 10 4.2830 13.5 778.4 181.6 959.9 0.0
22 10 11 0.0511 -21.2 -23.0 959.9 937.0 0.0
23 9 11 8.8716 9.2 755.4 181.6 937.0 0.0
24 3 15 0.1219 9.3 10.6 11.4 22.0 0.0
25 15 4 0.0450 9.3 3.9 22.0 25.9 0.0
26 17 6 0.0050 15.6 1.2 43.3 44.5 0.0
27 17 10 13.1861 8.3 916.6 43.3 959.9 0.0
28 16 17 0.0315 24.0 18.1 25.2 43.3 0.0
29 1 16 0.0073 58.8 25.2 -0.0 25.2 0.0
30 16 5 0.0050 34.8 6.1 25.2 31.3 0.0
31 10 13 0.0128 43.0 23.7 959.9 983.6 0.0

FAN OPERATING POINTS :
Fan Br JA JB R Q NVP FANHEAD AHP
no. Ns^2/m^8 m^3/s Pa Pa kW
1 14 18 1 0.0058 115.0 0.0 1080.5 124.3

Total AHP Required (kW) = 124.3

No. of Iterations done = 11 SumDQ = 0.0238425

ANNEXURE – V

MINE AND FAN CHARACTERISTIC CURVE OF
THE SAMPLE NETWORK

software for solving ventilation networks

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