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To start this small version of HYDROFLO 1.2 ...
- print this document file
- insert the diskette in drive A:
- move to that diskette drive by typing " A: " then press RETURN
- type " DEMO " and press RETURN.
HYDROFLO will then load.
A letter to interested parties...
" CAUTION " U.K. users should note that reference to " English Units ",
using the terms Gallons and GPM etc. MEANS U.S. Gallons and the
necessary conversions should be allowed for.
Dear Engineer,
On this disk or residing in this directory is a small version of
Engineering Software's HYDROFLO 1.2 along with instructions and 2
example problems. HYDROFLO performs the functions of a linear
hydraulic design tool for systems conveying fluids from point to
point. It runs on the IBM PC and the related family of PC/MS-DOS
microcomputers. We are excited about this software because there
are no comparable packages on the market today in terms of its
capabilities and price.
The design engineer essentially works in a worksheet type
environment, analyzing hydraulic elements and observing the bottom
line effects. HYDROFLO's extensive flexibility starts with the fact
that calculations can be performed in English or metric units and
use any type of fluid. All of Engineering Software's packages have
this basic capability. The full featured version includes the
UTILITY functions where with a single command the entire system's
diameter or friction can be changed to a new value and the system's
new operating point and pump specification be determined.
The engineer can specify that a pump be prescribed for a system
to meet a specified flow. Cavitation calculations are made and
reports detailing the system's head losses for various flows are
provided. This demo is a working version in that your own hydraulic
calculations can be performed and verified. It is a good way to
evaluate HYDROFLO risk free. Full screen graphics of the system
and pump operation are accessible along with the full functions
in the REPORT option.
The full featured version costs 250 Pounds Sterling, and includes
a User's Guide with numerous examples and a hydraulic reference handbook.
Tele-phone support is available at no cost to registered users.
ORDER FORM
Name: ________________________________ Title: ____________________
Firm: ________________________________ Phone: ____________________
Address: __________________________________________________________
__________________________________________________________
__________________________________________________________
Post Code: ____________________
Both 5 1/4" and 3 1/2" diskettes are included in all packages. Prices
subject to change.
U.K. PRICE LIST ------ APRIL 1991
Quantity Product Total
____________ HYDRONET 3.0 (550 Pounds Sterling each) _________
____________ HYDROFLO 1.2 (250 " " " " each) _________
____________ H-CALC 1.0 (120 " " " " each) _________
THE BUMPER BUNDLE PACKAGE :
____________ All Three (750 Pounds Sterling - Total) _________
ADD V.A.T. @ 17.5 % _________
Total Enclosed _________
Check or M.O. enclosed _____
Make checks payable and mail to:
PISCES ENGINEERING SERVICES
12 LOCH LAXFORD,
ST. LEONARDS,
EAST KILBRIDE G74 2DL
PHONE & FAX (03552) 43220
This is an abbreviated form of the HYDROFLO 1.2 manual...
INTRODUCTION
HYDROFLO is a tool for use in the design and validation of hydraulic systems.
It solves four common type of problems...
1) with a known pump, find the operating point of the system,
2) prescribe a pump for a system to drive a desired flow,
3) find the steady-state gravity flow for a pipeline, and
4) find element and total head losses for a non-pump system.
Pipe head losses in hydraulic systems can be calculated using the
Hazen-Williams equation for water or using the Darcy-Wiesbach equation for
any fluid. All system calculations can be performed in either English or
metric units. Two choices for head and flow units are available within each
unit system.
The user describes a hydraulic system consisting of inlets, outlets, valves,
fittings, pumps and pipes. If a pump is to be included in the system, the
user has the option of defining the pump curve or letting HYDROFLO prescribe
one for the system. Net positive suction head (NPSH) calculations for
cavitation determination and pump specification are provided. A menu of
valves and fittings is provided for selection. Given the fitting diameter,
the corresponding friction value is automatically used by HYDROFLO in the
head loss calculations. Custom friction values may also be entered. Default
system configurations of data file directories, fluid properties, head loss
equations, pressures and units systems can be set for automatic use at system
start-up.
Besides the basic ability to edit single element data, a large scale system
editing feature allows all system element diameters and friction values to be
changed with one command. A system analyzer is also available to scrutinized
data for incompleteness or inaccuracies. Output reports summarize suction,
discharge and total system head losses and detail individual element
velocities and head losses. A graph of the pump and system operating curves
is constructed for various flows and can be output to the screen and printer.
The current system data can be saved at any point of design in compact data
files.
UNDERLYING THEORIES
PIPES
Two head loss equations are available for determining the major friction
losses in pipes. The question of which equation to use depends on the system
fluid type and conditions. Certain conditions exist where either equation may
be used and comparing the results of both will confirm the proper modeling of
system operation.
The Hazen-Williams equation is available for water systems under turbulent
flow conditions and at 60 degrees F. (or fluids with kinematic viscosity
around 1.2x10-5 ft2/s). To use this equation, Hazen-Williams coefficients are
needed for all pipes. These coefficients have been determined by empirical
methods.
The fundamentally based Darcy-Wiesbach equation can be used for fluids of
various viscosities. The kinematic viscosity of the fluid in use must be
known as well as the piping material's specific roughness (sometimes called
absolute roughness). HYDROFLO uses a Colebrook-White algorithm to determine
the Moody friction factor f so manual look-up of values on the Moody diagram
is not needed.
FITTINGS AND VALVES
Minor friction losses through fittings and valves (which includes inlets and
exits) in water systems are modeled by multiplying the velocity head by the
appropriate resistance coefficient, K. HYDROFLO automatically uses the proper
values upon menu selection of the type and diameter. Custom K values may also
be input for fittings and valves not listed. It is important to check the
operating flow velocity to ensure the complete opening and therefore the
correct friction factor for the fitting.
Friction loss data for fittings and valves in fluid systems other than water
are not in reliable supply. The best approach is to assume turbulent flow
conditions and use the equivalent length method. The fittings can then be
represented as pipe elements in HYDROFLO.
Pressurized tanks at the inlet and exit may be modeled by inputing different
absolute pressures other than atmospheric at those points. Standard
atmospheric pressures at the inlet and exit would be used for open air intake
and discharges (see tables in APPENDIX). The inlet and exit pressure
difference is converted to equivalent feet (or meters) of liquid and is then
added to the elevation difference to obtain the total system static head.
SYSTEM CURVES
Two system curves are drawn on the graphs displayed in the REPORT - GRAPH
option of HYDROFLO. The two upward increasing curves are the combination of
all valve losses plus 90 and 110% of the pipe losses at the user specified
friction values. This provides a sensitivity analysis. The further the two
curves are apart, the more sensitive the system is to variations in pipe
friction coefficients. The other downward decreasing curve defines pump
operation. The hydraulic system will operate at the intersection of the system
and pump curves.
NPSHA
The Net Positive Suction Head Available (NPSHA) calculation is critical for
assessing cavitation possibilities in a hydraulic design using pumps. It is
the total suction head in feet (or meters) of liquid (absolute at the pump
centerline or impeller eye) less the absolute vapor pressure in feet (or
meters) of the liquid being pumped. If this calculation is of low or negative
value, you can be assured that the hydraulic design is near non-functional.
The situation can be remedied by placing the pump closer to the inlet or in
some way increase the suction dynamic head (or reduce the suction static lift).
PUMPS
A pump need not be incorporated into a design using HYDROFLO. The user can
merely be analyzing the head losses on a line composed of pipes and fittings.
HYDROFLO provides two ways to include pumps in your hydraulic design. You
may let HYDROFLO prescribe a pump that will supply the design flow for the
system or you may define a pump by inputing four points from the pump curve
and let HYDROFLO determine the actual operating point of the system.
Setting the DESIGN (ANALYSIS) FLOW amount in the STATUS option to a desired
value and requesting that a pump be prescribed when in DEFINE, forces HYDROFLO
to plot the curve of a pump that will supply the desired flow. The curve
presented is a ideal representation for a pump that has its optimal operating
point at the intersection of the system curve at the design flow.
Realistically, there may be no such pump in existence. But this gives the
engineer a starting point in the search for the required pump. Once a close
fit is found the actual pump curve may be entered and the actual operating
point may be determined. Throttle valves may then be used to to bring the
pump to the desired operating point.
If the user chooses to define a pump for the system, four points off the curve
are needed as input. HYDROFLO will fit these points to a cubic equation and
have a continuous function for the determination of pump head values.
START-UP
To start HYDROFLO, move to the disk drive that contains the HYDROFLO diskette
(ie, type A: or B: and press RETURN) then from that drive, type DEMO at the
DOS prompt and press RETURN.
HYDROFLO will take a few seconds to load. The first screen lists the features
in the full-feature version and where you can obtain it. Press any key to
start this small version of HYDROFLO. The top line of the main HYDROFLO
screen displays the HYDROFLO copyright notice on the left and the current
system filename on the right. The bottom line of the screen has the computer
time and date on the left and the right has an error space reserved for when
errors occur during system operation. The various keystrokes available as
responses for any HYDROFLO prompt is displayed on the line above the bottom
line of the screen.
HYDROFLO uses the following Lotus-style menus and keystroke syntax.
To select an option from a displayed menu:
- Use the space bar or cursor arrows to hi-light the option and press RETURN.
- or press the first character of the option name.
To exit from a lower menu or operation:
- Press the escape key (Esc). (Note: pressing escape repeatedly will
eventually bring you back to the main menu but never let you fully
exit to DOS. You must press "Y" at QUIT).
A help facility is available by pressing the F1 (function) key anywhere during
program execution.
When entering characters or numbers a toggle between insert mode and overtype
mode is available by pressing the insert (Ins) key.
MENU OPTIONS
FILE
The FILE option allows the retrieval from and storage to disk of data files.
The HYDROFLO data file names are appended with the extension of .FLO
automatically, the user need not type it in.
Select the RETRIEVE sub-option and a screen of data filenames will be
displayed. Use the space bar or cursor arrows to hi-light the desired
filename and press RETURN to retrieve the data in the file. The user may also
press function key F2 and input a custom path and filename. The data will
load and the main screen will return and the current filename will be
displayed in the upper right corner. The data is now available for use.
When SAVE is selected, the current path and filename are displayed if a system
has been loaded. Pressing RETURN retains the original filename and the user
is prompted with a warning:
file exists! Cancel Replace
Press "R" to overwrite the data file or "C" (or Esc) to cancel the operation.
Pressing escape (Esc) at the current path and filename presents the just the
current path ready for the user to enter a new filename. Pressing escape
again allows a totally new path and filename to be entered.
To clear the current data from HYDROFLO's memory (not erase the disk datafile)
without exiting the program, see the later section on utilities for editing.
STATUS
The STATUS option is used to set the default data file directory, head loss
equation, units systems, fluid properties, default friction coefficients and
pressures. The cursor arrows up or down (down arrow same as RETURN) are used
to move between the various input fields. Pressing the escape key (or coming
to the end of the menu) leads to the prompt:
Reset current system to new values? NO YES
If the new values aren't correct, press the escape key (Esc) or "N" to return
to the main menu. If they are correct, press RETURN and the system will use
the new parameter values and the following prompt will appear:
Update default parameter file? NO YES
This prompt will only appear if the previous prompt is answered with "Y" .
A "Y" response to this question will update the HYDROFLO default value file
that is loaded on start-up. The values displayed will be automatically set.
This is a time saver in establishing new designs. For example, if an engineer
always uses the Darcy-Wiesbach equation and analyzes oil conveyance systems,
HYDROFLO will start with these parameters automatically. On hard disk systems,
each person can have their own user directory and HYDROFLO configuration with
the desired parameters viewing only their data files while using a central
directory for the HYDROFLO system files.
PARAMETER DESCRIPTIONS
The DATA FILE DIRECTORY is the path where HYDROFLO looks for data files (shown
in the FILE - RETRIEVE option). HYDROFLO assures that the directory entered
exists before the user can move on to selecting which head loss equation to
use. On a hard disk system, this DATA FILE DIRECTORY should be set to the
user's own sub-directory.
Pressing RETURN or the cursor down arrow hi-lights the HEAD CALCULATION
EQUATION field. The user chooses either the Hazen-Williams or the
Darcy-Wiesbach equation by pressing arrow left or right then RETURN to select.
Press RETURN to select the head loss equation and hi-light the UNIT SYSTEM
field. The UNIT SYSTEM and FLOW UNITS are chosen as above by pressing arrow
right or left then pressing RETURN or arrow down to select.
The DESIGN (ANALYSIS) FLOW is the flow amount desired in the design. Press
"?" (question mark) to let HYDROFLO determine the operating flow in a gravity
or pumping system with known curve. The ANALYZE option will tell you if a
system is being interpreted correctly.
HEAD UNITS are selected like flow units above. if using units of psi or
Kpascals, be sure to set the proper liquid specific gravity.
The DEFAULT SPECIFIC ROUGHNESS or DEFAULT H-W COEFFICIENT can be set so that
the user has to only press RETURN when performing pipe data input. This does
not change any currently defined pipe friction coefficients. To change ALL
EXISTING pipe roughnesses to a new value, use the UTILITY - FRICTION option.
To change a specific existing pipe's roughness coefficient use the DEFINE
option and press F2 when positioned at the pipe.
The SPECIFIC GRAVITY value is needed for the conversion to head units other
than feet or meters of liquid.
The VAPOR PRESSURE is of the liquid at pumping temperature and is required for
the NPSHA (Net Positive Suction Head Available) calculation. If there is no
pump, this can be disregarded.
ATMOSPHERIC PRESSURE AT PUMP sets the pumps external pressure and the initial
values for the pressure at the inlet and exit. The initial default value is
for open tank sea level conditions (see tables in APPENDIX).
The KINEMATIC VISCOSITY is required when using the Darcy-Wiesbach equation.
The bottom of the STATUS screen displays your current hardware configuration.
DEFINE
The DEFINE option on the main menu allows you to ENTER and EDIT new system
elements. This section details the type of elements available for defining.
Once elements are defined, the user can EDIT, DELETE and INSERT elements as
described in the following EDIT section.
ELEMENTS AVAILABLE FOR DEFINING ...
INLETS
The first element in a design is an inlet. The user can select the type of
inlet from the inlet menu or press F2 and input custom values for inlet
description and resistance coefficient K. In both cases, the inlet elevation,
diameter and pressure are asked for. A non-zero diameter is needed to set up
the default system diameter. The pressure value is the absolute atmospheric
pressure at the surface of liquid supply level (barometric pressure from an
open tank or absolute pressure existing in a closed tank). This value of
pressure is needed for the NPSHA calculation. If using HYDROFLO to obtain
simple head loss values for other element than inlets, a zero value of K for
the inlet will omit inlet losses from REPORT option totals.
PIPES
The data entered for pipes include description, diameter, length and friction
factor. The optional descriptions for all elements are for the use of the
user for identification purposes. The friction factor that appears will be
either the default specific roughness or the default H-W coefficient and is
available for editing. The user is free to press RETURN and use this value
or input another friction value.
VALVES & FITTINGS
The fitting menu lists numerous types of valves and fittings. Use the cursor
arrow keys to hi-light the desired fitting and press return to select it. The
user will then be prompted for the fitting diameter and HYDROFLO will use the
appropriate K value for the fitting in its head loss calculations. The user
has the option of pressing F2 on the fitting menu and then inputing custom
descriptions and K values. NOTE: when custom values are input and when then
the UTILITY - DIAMETER option is used, HYDROFLO will not be able to update
the fitting's K value accordingly and the user must remember to update the
value.
PUMPS
The user has the choice of defining a pump curve for analysis or letting
HYDROFLO prescribe one for the system. If a curve is defined, the user must
describe four equal distant points off the curve as follows. The flow
increment sets the distance between the four points and is in units of flow.
The four points of head begin first with the shutoff head (The head at which
no flow can be push through the pump). The remaining three points from the
curve are the head values at the flow increment, twice the flow increment and
three times the flow increment. Once a pump is defined, the user can position
the element pointer at the pump and press F5 to obtain a plot of the pump
curve. The pump elevation is needed for the NPSHA calculation and the
suction side calculations. The atmospheric pressure, needed for NPSHA,
suction and discharge calculations when pressure tanks are used, is input in
the STATUS option.
EXITS
The last element in a hydraulic system is an exit. The K value for exits is
normally 1.0 but the user has the option of inputing any value. The pressure
at the exit will default to the pump's atmospheric pressure. If the discharge
is to be at a substantially different elevation or a closed tank, be sure to
update this value to the correct absolute pressure.
EDITING ...
The following keys can be used on defined elements within the DEFINE option.
EDIT (F2)
Use the cursor arrow keys to move the position pointer to an element and press
F2 (Function key 2). The original input screen is shown with the present
values. The user is allowed to edit or re-enter element data by inserting or
overtyping text or numeric characters. Pressing RETURN or pressing arrow down
at a data position retains the original values shown. Pressing escape jumps
out of the editing of the current element and progresses to the next element.
DELETE (F3)
When pointing at a defined element, pressing the F3 key prompts the user for
deletion of the element. The user confirms the request and the element is
removed. Pressing "N" or Esc retains the element.
INSERT (F4)
When pointing at a defined element, pressing the F4 key prompts the user for
inserting an element before that element. Again the user can confirm the
request and select the type of element to insert. Pressing "N" or Esc aborts
the operation.
PLOT (F5)
When positioned at a pump that is not to be prescribed by HYDROFLO, the curve
for the pump is plotted on capable displays. Pressing F6 while the plot is
shown sends the graphics display to the graphics printer. Pressing any other
key returns to the defined element screen pages.
PG-UP and PG-DN
These keys allow fast movement within the pages of defined elements.
REPORT
The REPORT option allows the output of system element data, summaries of head
loss results and system curve plots. All output can be directed to the
SCREEN, FILE or PRINTER.
The SUMMARY sub-option displays the current systems fluid properties, NPSHA
calculation, static head data, system head loss totals and pump prescription.
The DETAIL sub-option gives a listing of all elements with their friction,
diameters, velocities and head losses for a given flow. Pipe details include
lengths. Inlet, exit and pump details include elevations and absolute
pressures.
The GRAPH sub-option displays the system plot with pump curve and operating
point. Pressing F6 sends the displayed graph to the printer. Pressing Esc
(escape key) while the printer receives information aborts the printing
operation.
UTILITIES
The DIAMETER sub-option allows the mass editing of ALL element diameters.
For fittings that were selected from the fitting menu, the corresponding K
value for the new diameter will be set also. Custom fittings will have their
diameters changed so that velocities will be correct but the K values may not
be correct and must be checked and updated by the user.
The FRICTION sub-option changes ALL pipe friction values to a new value.
The ERASE sub-option clears HYDROFLO's memory of the currently defined system.
You are starting over. NOTE: Be sure all wanted work is saved to disk with
the FILE - SAVE option before using ERASE.
ANALYZE
ANALYZE is a powerful option that can spot potential problems in your design.
The first few lines of output state HYDROFLO's interpretation of your problem
(whether a pump, gravity or forced flow problem) and the action to be taken
(operating point to be determined, head losses found, etc.). In general if
HYDROFLO is unable to plot a system graph or outputs strange results, ANALYZE
may pick up the problems cause. The warnings that this option provides are
strictly informational. If HYDROFLO is being used to obtain simple head loss
calculations for a few elements, the warning that there is no exit or pump in
the system, is informational and of no concern. However, if HYDROFLO is being
used to analyze an hydraulic system complete with pump, any warning message
that this option provides may be critical. ANALYZE should be run often so
that it's warnings can be interpreted correctly from experience.
QUIT
This option is used to exit HYDROFLO. Be sure that any altered work since the
last save is not needed. The user will be prompted as to whether they really
wish to leave HYDROFLO and exit to the operating system. Pressing "N"
returns the user to the main menu.
DESIGN METHODS
A general design methodology for using HYDROFLO follows:
1.) Enter the STATUS option and set the head loss equation, units, fluid
parameters, design flow and pressures (if these conditions are going to be
used for most new designs, you may wish to place them in the default parameter
file for automatic start-up).
2.) Enter the DEFINE option and enter all element data starting with the
inlet.
3.) When all data is entered, use the FILE - SAVE option to save the
current data. Perform file saves often so that work is not lost.
4.) Run the ANALYZE option to identify any incomplete or inaccurate data.
5.) Use the REPORT option to obtain a summary of system head losses,
detailed reports of all element data and a graph of the system and pump curves.
6.) Use the UTILITY options to investigate the effects on pump
specification that differing diameters and materials (friction) have.
DESIGN TIPS...
- If a pump is to be prescribed for the system, the design flow is the desired
flow for the system.
- When a pump is restricted to being positioned at a certain location and the
NPSHA is low, the diameters of the suction side lines can be increased to
minimize these intake losses.
- When a pump is not restricted to a specific location, the insert element
function (F4) and delete element function (F3) can be used to move the pump to
various spots in the line to provide adequate NPSHA.
- Trade offs existing between system element diameters (pipe and fitting
costs) and pump size (pump costs) can tested by using the UTILITY - DIAMETER
option and letting HYDROFLO prescribe the pump. The optimal solution would
be find the minimum total cost for the system while meeting the design flow
and providing an adequate NPSHA.
USING FLUIDS OTHER THAN WATER
HYDROFLO allows the analysis of hydraulic systems using fluids other than
water. If a fluid has a kinematic viscosity near that of water at 60 degrees
F and is used at turbulent conditions, then the Hazen-Williams equation can be
used. If those conditions are not met, the Darcy-Wiesbach equation should be
used. The kinematic viscosity and the piping materials specific roughness
must be known. For valve and fitting friction head losses, the best approach
is to assume turbulent flow conditions and use the equivalent length method.
The friction coefficients automatically used from the fitting and valve menu
are strictly for water.
SAMPLE PROBLEMS
DEMO PROBLEM 1
An engineer is to provide the pump curve and system pipe size needed for
the hydraulic system shown opposite. A flow of 250 gpm is desired. The
Hazen-Williams equation will be used to compute pipe head losses in this water
system.
The file DEMO1.FLO on the demo disk contains the data for this problem and
can be retrieved using the FILE - RETRIEVE option. The following text
describes the step by step procedure for creating this file.
First, enter HYDROFLO's STATUS option by pressing "S" at the opening
screen or press the space bar once to move to and hi-light the "STATUS"
phrase, then press the RETURN (ENTER) key. Once in the STATUS option, press
the arrow down key to move past the DATA FILE DIRECTORY field to the HEAD
CALCULATION EQUATION field. If "Hazen-Williams" is not displayed, press the
arrow right or left key to switch from the displayed "Darcy-Wiesbach"
statement and press the arrow down key to move to the UNIT SYSTEM field. It
should say "English" and if not, pressing arrow left or right will switch
to the desired unit system. FLOW UNITS are selected as the above parameters
were, and we use "gpm" not "cfs" . The DESIGN (ANALYSIS) FLOW is a string
input field and so type in "250." and press the arrow down (or RETURN) key.
If any parameter field is not correct, press the arrow up key until arriving
at the desired field, then edit it accordingly. For HEAD UNITS we want "feet
of liquid" not "psi" and it is selected as FLOW UNITS was above. Type in
"100." and press RETURN for the DEFAULT H-W COEFFICIENT. This system uses
water and to set the SPECIFIC GRAVITY at 1.0, just press RETURN. The VAPOR
PRESSURE of water at 60 degrees F is ".25" psia so that value is entered and
RETURN is pressed. Enter "14.2" for the atmospheric pressure at the pump and
press RETURN. The following prompt will now appear...
Update current system to new values: NO YES
If the values set are correct, press RETURN or " Y " to accept the new
values. If they aren't, we could press RETURN anyway to accept the values,
and then go back to the STATUS option again to edit desired fields. If we
chose not to accept the new values at all, we could press "N" or Esc to abort
the process. When the values are correct and are accepted, a prompt to update
the default parameter file appears. If we wanted to use the new values each
time HYDROFLO was started, we would answer with a "Y", but for these
demonstration purposes we instead press RETURN.
Discharge elev = 1080.63'
Supply elev = 1012.51'
PRESSURES:
pump elev = 1005.74'
press. at pump = 14.2 psia
PIPES:
Steel sched-40 4"(est)
H-W coef = 100
(page 3-8 Cameron)
Spec Rough = .00015
(page 3-5 Cameron)
FLUID:
Water at 60 deg. F.
Vap. press. = .25 psia
(Page 4-20 Cameron)
Kin. vis = .00001216 ft2/sec
(pg 4-4 & 4-25 Cameron)
DETAILED REPORT - INDIVIDUAL ELEMENTS
(System: DEMO1.FLO) @ flow = 250.00 gpm
El# Description Fric Dia Vel HL
(inches) (ft/s) (feet)
1 Inlet Flush - sharp edged 0.50 4.00 6.38 0.32
Elev = 1012.51 feet Press = 14.20 psia
2 Pipe l= 50.00 100.00 4.00 6.38 3.35
3 Fitt Std. elbow-long radius 90 deg. 0.27 4.00 6.38 0.17
4 Pipe l= 25.00 100.00 4.00 6.38 1.67
5 Fitt Stop check valves 6.80 4.00 6.38 4.31
6 Fitt Plug valve Straightway 0.31 4.00 6.38 0.20
7 Pipe l= 6.00 100.00 4.00 6.38 0.40
8 Pump pump prescribed for system
Elev = 1005.74 feet Press = 14.20 psia
9 Pipe l= 6.00 100.00 4.00 6.38 0.40
10 Fitt Butterfly valve 0.77 4.00 6.38 0.49
11 Pipe l= 50.00 100.00 4.00 6.38 3.35
12 Fitt Std. elbow-long radius 90 deg. 0.27 4.00 6.38 0.17
13 Pipe l= 500.00 100.00 4.00 6.38 33.48
14 Fitt Stop check valves 6.80 4.00 6.38 4.31
15 Pipe l=1000.00 100.00 4.00 6.38 66.97
16 Exit 1.00 4.00 6.38 0.63
Elev = 1080.63 feet Press = 14.20 psia
Back at the main HYDROFLO menu, we select the DEFINE option to perform
data input of the elements shown on the opposite of this side of the page.
Starting with the inlet (the element data is listed in output report opposite
side of paper). When DEFINE is selected, the Inlet menu appears and the
description "Flush - sharp edged" is hi-lighted by pressing arrow down once,
then pressing RETURN to select. A smaller sub-window appears that displays
the inlet description and resistance value K, and the cursor is positioned at
the elevation field. An elevation of "1012.51" is input and the user presses
RETURN. Our initial estimate of system diameter is 4" and that value is
entered thus setting up the default diameter for the rest of the system. The
pressure at the inlet is the next input and since this is an open surface
intake, press RETURN to use the default atmospheric pressure (set up for the
pump in the STATUS option).
The element menu is automatically displayed after the inlet data input and
the position pointer is set to element #2. Element #2 is a pipe so RETURN is
pressed and an optional description can be entered. The next field displays
the default diameter set up for the inlet and RETURN can be pressed to accept
the value. A length of "50." feet is entered for the pipe and the RETURN
key is pressed. The default Hazen-Williams coefficient appears and the RETURN
key is again pressed to accept the value.
The element menu is displayed and the pointer is positioned at element #3.
This element is a fitting and the word "Fitt" is hi-lighted by pressing the
arrow down key and the RETURN key is pressed to select it and the fitting and
valve menu appears. Again using the cursor arrow keys, the statement "Std.
elbow long radius 90 deg" is hi-lighted and the RETURN key is pressed. The
default diameter is displayed and RETURN is pressed to accept the default
value. HYDROFLO automatically uses the correct resistance coefficient K, for
inlets, exits, valves and fittings selected from it's internal menus.
The data for elements #4 through #7 are input in the same manner as the
previous elements.
When pump position #8 is reached, the phrase " pump " is hi-lighted on
the element menu and the RETURN key is pressed. The pump window appears and
offers the choice of "define a pump for analysis" or "let HYDROFLO
prescribe a pump" for the system. In this problem, a pump is to be
prescribed so press the arrow down key and then press RETURN. The pump
elevation field is displayed and the value "1005.74" is entered an RETURN
is pressed.
The data for elements #9 through #15 is entered (according to data listed
on opposite side, detailed report) up to exit element #16.
At exit element #16, the phrase " exit " is hi-lighted on the element
menu and the RETURN key is pressed. A window is displayed with the exit's
data and the cursor is positioned at the description field. The description
is optional. The next input field is the resistance coefficient, K. For most
exits a value of 1.0 is used but the value may be edited. In the elevation
field a value of "1080.63" is entered the RETURN key is pressed. We press
RETURN again to accept the default diameter value and again to accept the
default pressure since this is an open surface exit.
The "defined" mode is entered where by pressing the arrow left or right
(or page-up, page-dn) key can position the pointer at an element and display
it's data. We can edit an individual element's data by positioning the
pointer at the element and pressing F2, insert an element by pressing F4 or
delete an element by pressing F3.
With the full featured version we could now select FILE , then SAVE and
specify a filename for our data to reside in. At the main menu run the
ANALYZE option to determine if any potential problems exist in the system.
From the main menu, the REPORT option can be used to preview results of
the analysis. The operating point is determined to be at 250 gpm and 188
feet head with a NPSHA (Net Positive Suction Head Available) of 28.5 feet and
a general system velocity of 6.38 ft/sec. Other system diameters can be
tested with the full featured of HYDROFLO using the UTILITY - DIAMETER
option but 4" appears to be the best. With the demo disk, the DEFINE option
is used to edit individual element diameters using the F2 key.
The graph obtained with the REPORT - GRAPH option (CAPACITY vs. HEAD
graph, following) and the NPSHA value (end of SUMMARY OF PUMPING SYSTEM DATA)
would be taken to a pump manufacturer to find an appropriate pump. Once a
close operating pump is found, it's curve is input to the system by
positioning the DEFINE pointer to the pump position and pressing F2, selecting
"define a pump" (the top line option) then inputing it's data according to
the previously discussed DEFINE - PUMPS section and the actual operating point
will be found.
SUMMARY OF PUMPING SYSTEM DATA (System: DEMO1.FLO)
CONFIGURATION: Hazen-Williams Eq.
Flow = 250.00 gpm
FLUID PROPERTIES:
Specific Gravity = 1.000
Vapor Pressure = 0.25 psia
STATIC HEADS:
Suction Elev Head = 6.77 feet
Discharge Elev Head = 74.89 feet
Exit - inlet press. = 0.00 feet
Total Static Head = 68.12 feet
NPSHA CALCULATION:
Supply pressure = 14.20 psia (abs)
Vapor pressure = 0.25 psia (abs)
Suction static head = 6.77 feet
Suction dynamic hd = 10.41 feet @ design flow
NPSHA = 28.58 feet
HEAD LOSSES (in feet)
FLOW (gpm)
SUCTION SIDE 125 250 375
MINOR LOSSES:
Valves & fittings 1.25 4.99 11.23
MAJOR LOSSES:
Pipe HL using Hazen-Williams Eq 1.50 5.42 11.48
STATIC SUCTION HEAD:
Inlet - pump elev + pressures 6.77 6.77 6.77
TOTAL SUCTION HEAD:
Head (+), lift (-) 4.02 -3.64 -15.94
DISCHARGE SIDE
MINOR LOSSES:
Valves & fittings 1.40 5.60 12.59
MAJOR LOSSES:
Pipe HL using Hazen-Williams 28.90 104.20 220.61
STATIC DISCHARGE HEAD:
Exit - pump elev + pressures 74.89 74.89 74.89
TOTAL DISCHARGE HEAD:
Static head plus friction losses 105.19 184.69 308.10
TOTAL SYSTEM LOSSES
TOTAL SUCTION HEAD:
Static head + friction losses 4.02 -3.64 -15.94
TOTAL DISCHARGE HEAD:
Static head + friction losses 105.19 184.69 308.10
TOTAL SYSTEM HEAD:
Suction and discharge heads 101.18 188.33 324.04
Pump Prescription:
Design operating point: FLOW = 250.00 gpm
HEAD = 188.33 feet
NPSHA = 28.58 feet
DEMO PROBLEM 2
A pump is to be specified for the oil conveyance system displayed opposite.
A flow of .4 m3/sec is to be delivered by the 30 cm. diameter system. The
Darcy-Wiesbach equation will be used to calculate pipe head losses and the
valves will be modeled as pipes using the equivalent length method. The file
DEMO2.FLO on the demo disk contains the data for this problem and can be
retrieved using the FILE - RETRIEVE option.
Using HYDROFLO's STATUS option, we set the Darcy-Wiesbach equation for
use in calculating pipe head losses. The DESIGN (ANALYSIS) FLOW will be set
at .4 m3/sec. Within the metric unit system we setup flow units of m3/sec
and head units of meters of liquid. We will also set a default specific
roughness of .03 mm for the steel pipe. Specific gravity and kinematic
viscosity are set to the values listed opposite.
Using the DEFINE option, we give the inlet a K value of 0.0 because all
fittings (except the pump) are being modeled as equivalent lengths of pipe.
On the inlet data input, press arrow up when at the elevation field and enter
"0.0" for the friction K value. All the other data for the inlet is needed so
that static head and NPSHA calculations are performed correctly. Using the
chart on page 3-121 in Cameron (included with full featured version) we line
up the diameter 11.8 inches (30 cm.) and the point for an ordinary entrance
and we get 17 feet of pipe length which works out to 5.18 meters. Pipe element #2 has a length of 30 meters so we
have added this length to it. The same process is used for the exit and its
equivalent length is add to pipe #24 and a K value of 0.0 is given to the exit.
The rest of the data is entered (pipes entered normally and valves as
pipes) along with the pump which we request to be prescribed.
The ANALYZE option will tell us that the inlet and exit have zero for
coefficients. This is as intended. The losses for the inlet and exit are
included in the adjacent pipes length.
The prescribed pump's and system's curve along with the system summary of
head losses is shown on the back of this page.
Tank B elev = 178.15 m
Tank A elev = 132.63 m
Pump elev = 125.79 m
PIPING SYSTEM:
Steel sched-40 30 cm.
Specific Rough = .03 mm
PRESSURES:
Atm press @ pump = 99.285 Kpa
Tank A = 121.39 Kpa (closed)
Tank B = 103.54 Kpa (closed)
FLUID:
SG = .86 Crude oil at 120 deg. F.
Kinematic Vis = 4.1 centistokes = 4.1e-6 m2/sec
Vap. press. = .5 KPa
DETAILED REPORT - INDIVIDUAL ELEMENTS
(System: DEMO2.FLO) @ flow = 0.40 m3/sec
El# Description Fric Dia Vel HL
(cm.) (mtr/s) (meters)
1 Inlet Inward projecting 0.00 30.00 5.66 0.00
Elev = 132.63 meters Press = 121.39 Kpa
2 Pipe l= 35.18 3.00e-002 30.00 5.66 2.83
3 Pipe Fitt -elbow-45 deg l= 4.27 3.00e-002 30.00 5.66 0.34
4 Pipe l= 30.00 3.00e-002 30.00 5.66 2.41
5 Pipe Fitt -Tee-thruflo l= 5.79 3.00e-002 30.00 5.66 0.47
6 Pipe l= 15.00 3.00e-002 30.00 5.66 1.21
7 Pipe Fitt -Tee-thruflo l= 5.79 3.00e-002 30.00 5.66 0.47
8 Pipe l= 47.00 3.00e-002 30.00 5.66 3.78
9 Pipe Fitt -Sw chk val l= 22.86 3.00e-002 30.00 5.66 1.84
10 Pipe Fitt -Plug Val Str l= 4.27 3.00e-002 30.00 5.66 0.34
11 Pipe l= 4.00 3.00e-002 30.00 5.66 0.32
12 Pump pump prescribed for system
Elev = 125.79 meters Press = 99.29 Kpa
13 Pipe l= 4.00 3.00e-002 30.00 5.66 0.32
14 Pipe Fitt -Plug val str l= 4.27 3.00e-002 30.00 5.66 0.34
15 Pipe l= 150.00 3.00e-002 30.00 5.66 12.07
16 Pipe Fitt -elbow lr 90 l= 7.62 3.00e-002 30.00 5.66 0.61
17 Pipe l= 85.18 3.00e-002 30.00 5.66 6.85
18 Exit 0.00 30.00 5.66 0.00
Elev = 178.15 meters Press = 103.54 Kpa
SUMMARY OF PUMPING SYSTEM DATA (System: DEMO2.FLO)
CONFIGURATION: Darcy-Wiesbach Eq.
Flow = 0.40 m3/sec
FLUID PROPERTIES:
Specific Gravity = 0.860
Vapor Pressure = 0.50 Kpa
Kinematic Viscosity = 4.1e-006 m2/sec
STATIC HEADS:
Suction Elev Head = 6.84 meters
Discharge Elev Head = 52.36 meters
Exit - inlet press. = -2.12 meters
Total Static Head = 43.40 meters
NPSHA CALCULATION:
Supply pressure = 121.39 Kpa (abs)
Vapor pressure = 0.50 Kpa (abs)
Suction static head = 6.84 meters
Suction dynamic hd = 14.01 meters @ design flow
NPSHA = 7.16 meters
HEAD LOSSES (in meters)
FLOW (m3/sec)
SUCTION SIDE 0.20 0.40 0.60
MINOR LOSSES:
Valves & fittings 0.00 0.00 0.00
MAJOR LOSSES:
Pipe HL using Darcy-Wiesbach Eq 3.87 14.01 30.05
STATIC SUCTION HEAD:
Inlet - pump elev + pressures 9.46 9.46 9.46
TOTAL SUCTION HEAD:
Head (+), lift (-) 5.59 -4.55 -20.59
DISCHARGE SIDE
MINOR LOSSES:
Valves & fittings 0.00 0.00 0.00
MAJOR LOSSES:
Pipe HL using Darcy-Wiesbach 5.58 20.20 43.32
STATIC DISCHARGE HEAD:
Exit - pump elev + pressures 52.86 52.86 52.86
TOTAL DISCHARGE HEAD:
Static head plus friction losses 58.44 73.07 96.19
TOTAL SYSTEM LOSSES
TOTAL SUCTION HEAD:
Static head + friction losses 5.59 -4.55 -20.59
TOTAL DISCHARGE HEAD:
Static head + friction losses 58.44 73.07 96.19
TOTAL SYSTEM HEAD:
Suction and discharge heads 52.85 77.62 116.78
Pump Prescription:
Design operating point: FLOW = 0.40 m3/sec
HEAD = 77.62 meters
NPSHA = 7.16 meters
APPENDIXES
Darcy-Wiesbach specific roughnesses in mm.
(Source - Pipeflow analysis by Stephenson, 1984)
Finish Smooth Average Rough
-------------------------------------------------------------------------
Glass, drawn metals 0 0.003 0.006
Steel, PVC or AC 0.015 0.03 0.06
Coated steel 0.03 0.06 0.15
Galvanized, vitrified clay 0.06 0.15 0.3
Cast iron or cement lined 0.15 0.3 0.6
Spun concrete or wood stave 0.3 0.6 1.5
Riveted steel 1.5 3 6
Foul sewers, tuberculated
water mains 6 15 30
Unlined rock, earth 60 150 300
COMMON CONVERSIONS
MULTIPLY BY TO GET
feet .30480 meters
meters 3.2808 feet
psi 6.8948 Kpa
Kpa .1450 psi
gpm (U.S.) .06309 liters per second
cfs 448.8 gpm (U.S.)
cubic meters/sec 1000. liters per second
feet of liquid SG/2.31 psi
psi 2.31/SG feet of liquid
meters of liquid SG/.102 Kpascals
Kpascals .102/SG meters of liquid
centistokes 1x10-6 square meters / sec.
ATMOSPHERIC PRESSURES AT VARIOUS ALTITUDES
ALTITUDE PRESSURE
FEET METERS Psia Kpa
-1000 -304.8 15.2 104.8
-500 -152.4 15.0 103.4
0 0 14.7 101.4
500 152.4 14.4 99.3
1000 304.8 14.2 97.9
1500 457.2 13.9 95.8
2000 609.6 13.7 94.5
2500 762.0 13.4 92.4
3000 914.4 13.2 91.0
3500 1066.8 12.9 88.9
4000 1219.2 12.7 87.6
4500 1371.6 12.4 85.5
5000 1524.0 12.2 84.1
5500 1676.4 12.0 82.7
6000 1828.8 11.8 81.4
6500 1981.2 11.5 79.3
7000 2133.6 11.3 77.9
7500 2286.0 11.1 76.5
8000 2438.4 10.9 75.2
8500 2590.8 10.7 73.8
9000 2743.2 10.5 72.4
9500 2895.6 10.3 71.0
10000 3048.0 10.1 69.6
15000 4572.0 8.3 57.2
20000 6096 6.7 46.2
30000 9144 4.4 30.3
40000 12192 2.7 18.6
50000 15240 1.7 11.7