Component
reference
This section
describes the properties and the default values of all the
hydraulic components. For each component we show the
properties screen as it appears to the operator, and a table
showing the internal representation of those same
properties. Some properties in the table are only
visible to the computation engine and cannot be modified
directly through the graphical user interface (for instance,
adding a line to the comments' section modifies the
QtyComments property). The tables are used to provide
explanations of selected properties.
The
properties shown in gray in the tables are called project
properties and can only be edited within the context of an
assembly (they are not intrinsic component properties).
Please note that project properties do not have default
values and that the following tables show project property
values only for the purpose of exemplification.
The accumulator component dialog box is
show below:
Figure 31
|
Property |
Description |
|
[accum_1]
|
Unique identifier for this
component |
|
Cn="" |
Comment line where n is an
integer >=1 |
|
QtyComments=n |
|
|
Type_Of_Gas=nitrogen |
Gas can be nitrogen, helium or
ideal. Note: above about 5000 psia, “ideal” is
seriously in error when compared to the real gas. |
|
Gas_Exponent=table |
This can be “table” or a real
number. For the most accurate results use “table” |
|
Empty_Volume=10 gal |
Gas volume when the accumulator is
empty of fluid. This is the actual volume of gas
present when the accumulator is precharged, which is
usually different from the “nominal” volume of the
bottle. |
|
Time_Constant=45 sec |
This parameter is a measure of the
rate at which the temperature of the gas approaches the
ambient temperature. 45 seconds has proven to be
accurate for cylindrical float and piston type
accumulators, with either helium or nitrogen. In
the absence of better data, use 45 seconds. |
|
Precharge=1500 psi |
This is the precharge pressure at
the ambient temperature. If an absolute pressure
unit like psi(a) is not used, then the hydraulic fluid
depth head is added to get the absolute pressure. |
|
Depth=1000 ft |
Depth below the HPU |
|
Ambient_T=40 F |
The gas always tries to settle back
to this temperature. |
|
Starting_T=20 F |
Temperature of the precharge gas at
the start of the simulation |
|
Initial_Fill=3000 psi |
This the pressure (or volume) of
fluid in the accumulator at the start of the simulation.
Important: If you want to start with an empty
accumulator, do not use a pressure here… use 0 gal or
some other volume unit. If you specify a pressure,
round off errors may result in a tiny squirt of fluid
that you do not expect. |
|
QtyOutputs=4 |
|
|
O1=Gas_P,y,psi,-1 |
(Output) Internal pressure. May be
absolute or gauge (relative to fluid hydraulic head). |
|
O2=Gas_T,n,F,-1 |
(Output) Gas average temperature as
a function of time. “Average” means over the
internal volume at a particular point in time. |
|
O3=Gas_n,n,,-1 |
(Output) Gas law exponent. If
you specify an exponent this will be boringly constant.
If you use the table, the exponent will change with
temperature and pressure. |
|
O4=Fluid,y,gal,-1 |
(Output) Amount of fluid in the
accumulator |
When put on
the end of a line, this component does not allow any fluid
to exit the line through that end. The blocked component
dialog box is shown below:
Figure 32
|
Property |
Description |
|
[[Blocked_1] |
Unique identifier for this
component |
|
Cn = "" |
Comment line where n is an
integer >=1 |
|
QtyComments = n |
|
|
StopOnPressure=yes |
You can have the simulation stop
when the pressure at this blocked end passes through a
reference pressure. If you answer no, then
pressure is ignored and the simulation will end base on
time alone. |
|
Direction=rising |
If you are stopping on the basis of
pressure, this determines whether the simulation is
stopped when the pressure is above or below the
reference point. |
|
Pressure=1500 psi |
This is the reference pressure for
stopping the simulation. |
The branch
is used to connect more than one line to the output of a
discharge device. The branch component does not have a
component properties' editor.
|
Property |
Description |
|
[Branch_1]
|
Unique identifier for this
component |
|
Cn="" |
Comment line where n is an
integer >=1 |
|
QtyComments=n |
|
|
Qty_Branches=2 |
This value cannot be modified |
The document component dialog box is
show below:
Figure 33
|
Property |
Description |
|
[Document_1]
|
Unique identifier for this
component |
|
Cn="" |
Comment line where n is an
integer >=1 |
|
QtyComments=n |
|
|
Project="Titanic" |
A line identifying the project |
|
Client="Oil Gulf" |
A line identifying the client |
|
PressureUnit=psi,-1 |
(See explanation below) |
|
FlowUnit=gpm,-1 |
(See explanation below) |
|
VolumeUnit=gal,-1 |
(See explanation below) |
|
SpeedUnit=ft/sec,-1 |
(See explanation below) |
|
TimeUnit=sec,-1 |
(See explanation below) |
This
component holds general descriptions and explanations
related to a simulation. There must be one, and only one of
these in each assembly that can be run. The computation
engine uses the units for any computed quantity that does
not otherwise have a unit assigned to it.
The fluid component dialog box is show
below:
Figure 34
|
Property |
Description |
|
[Fluid_1] |
Unique identifier for this
component |
|
Cn = "" |
Comment line where n is an
integer >=1 |
|
QtyComments = n |
|
|
T1=2.5 C |
Two temperature points to allow
interpolating a viscosity at the operating temperature.
Temperature must be >0 absolute. A logarithmic
interpolation is used, not linear. |
|
T2=25 C |
|
P1=0 bar |
Two pressure points to allow
interpolating a viscosity and density at the operating
pressure. |
|
P2=300 bar |
|
V_at_P1T1=4.38 cs |
Viscosity matrix for interpolating
a fluid viscosity at the working temperature and
pressure. |
|
V_at_P2T1=4.45 cs |
|
V_at_P1T2=1.93 cs |
|
V_at_P2T2=1.96 cs |
|
Density_at_P1=1.011 |
Two density points to allow
interpolating a density at the operating pressure. |
|
Density_at_P2=1.027 |
|
Bulk_Modulus=315.378E3 psi |
This is the mathematical inverse of
the fluid compressibility. |
|
Ta=40 F |
The ambient temperature is used to
compute a
Viscosity for all fluid
calculations. |
This component holds fluid properties.
There must be one of these in each assembly that can be run.
The hose component dialog box is show
below:
Figure 35
Property |
Description |
|
[hose_1] |
Unique identifier for this
component |
|
Cn = "" |
Comment line where n is an
integer >=1 |
|
QtyComments = n |
|
|
ID=0.51 IN |
Hose internal diameter |
|
Roughness=10E-6 IN |
Hose roughness |
|
FastFraction=0.55 |
This is the fraction of the viscous
friction that occurs with the fast time constant. |
|
ExpansionUnit=CC/FT |
Can also be % (applies to the
expansion table) |
|
PressureUnit=PSI |
(Applies to the expansion table) |
|
TimeUnit=SEC |
(Applies to the expansion table) |
|
P1=0.13, 25,
0.14700, 60, 80 |
Expansion table points. There can be any number of them.
The format is:
Px=exp,
pres, ratio, fast, slow.
Exp
is the expansion
Pres
is the pressure
Ratio
is the ratio of elastic to viscoelastic expansion
Fast
is the fast viscoelastic time constant
Slow
is the slow viscoelastic time constant
Here are
some guidelines for picking Ratio (and for refining
Exp). Pres and Exp are normally given by the hose
manufacturer in the expansion curve for the hose.
Make a plot of the manufacturer’s data. The curve
should be smooth and get flatter as pressure is
increased. Any bumps or oscillations should be
taken out or discussed with the manufacturer to see if
they actually occur in the real hose.
Then,
look at the speed of sound that results in the
simulation. Speed of sound should increase with
pressure. 1000 ft/sec is quite slow. At
operating pressures, speed of sound is generally near
2500-2700 ft/sec, but a case that reached 3000 ft/sec.
Has not been observed. |
|
P2=0.23, 50,
0.15600, 60, 80 |
|
P3=0.36, 100,
0.18300, 60, 80 |
|
P4=0.53, 200,
0.22100, 60, 80 |
|
P5=0.74, 400,
0.27600, 60, 80 |
|
P6=1, 800,
0.35000, 60, 80 |
|
P7=1.39, 1600,
0.43600, 60, 80 |
|
P8=1.71, 2400,
0.49300, 60, 80 |
|
QtyPoints=8 |
Number of expansion table points
(computed automatically) |
|
Length=5 km |
Length of hose |
|
QtyLines=1 |
Number of identical lines in
parallel |
|
Wavespeed_Unit=ft/sec |
Unit of measure to use when
displaying the calculated wave speed. |
|
Wavespeed_Dec=0 |
Number or decimals for displaying
wave speed |
|
Initial_Cndx=1500 psi |
Initial pressure or flow in the
hose component |
|
Save_Cndx=y |
Save final conditions for use in
the next simulation |
|
Read_Cndx=y |
Read final conditions from the
previous simulation |
|
QtyOutputs=8 |
|
|
O1=Src_P,y,psi,-1 |
Pressure at source end of this line |
|
O2=Src_Q,y,gpm,-1 |
Flow rate at source |
|
O3=Src_Qtot,n,gal,-1 |
Totalized flow at source |
|
O4=Dis_P,y,psi,-1 |
Pressure at discharge end of this
line |
|
O5=Dis_Q,y,gpm,-1 |
Flow rate at discharge |
|
O6=Dis_Qtot,n,gal,-1 |
Totalized flow at discharge |
|
O7=Re,n,,-1 |
Reynolds's number at the source end |
|
O8=f,n,,-1 |
Friction factor at the source end |
Expansion table points are entered
using the second page of the hose component dialog box
Figure 36
The inlet port component uses a generic
dialog box as show below:
Figure 37
|
Property |
Description |
|
[ConnIn_1] |
Unique identifier for this
component |
|
Cn = "" |
Comment line where n is an
integer >=1 |
|
QtyComments = n |
|
This
component is used for creating subassemblies and utilizing
these as building blocks for creating more complex
assemblies. A port component will represent an inlet port in
the subassembly icon once entered in the parent assembly.
Components or assemblies that precede this one can connect
to this inlet port.
The inlet
port component uses a generic dialog box as show below:
Figure 38
|
Property |
Description |
|
[ConnOut_1] |
Unique identifier for this
component |
|
Cn = "" |
Comment line where n is an
integer >=1 |
|
QtyComments = n |
|
This
component is used for creating subassemblies and utilizing
these as building blocks for creating more complex
assemblies. A port component will represent an outlet port
in the subassembly icon once entered in the parent assembly.
This port is used to connect an assembly to components or
assemblies that follow this one.
The pressure
discharge component supplies or establishes a pressure at
the discharge end of a line. The pressure discharge
component dialog box is show below:
Figure 39
|
Property |
Description |
|
[PressDis_1] |
Unique identifier for this
component |
|
Cn="" |
Comment line where n is an
integer >=1 |
|
QtyComments=n |
|
|
Pressure=1500 psi |
|
The pressure
source component supplies or establishes a pressure at the
source end of a line. The pressure source component
uses the same dialog box as the pressure source component.
|
Property |
Description |
|
[PressSrc_1]
|
Unique identifier for this
component |
|
Cn="" |
Comment line where n is an
integer >=1 |
|
QtyComments=n |
|
|
Pressure=1500 psi |
|
The pump
component represents two pumps, one electric, and one air
driven. Both feed the same output. Both pumps, one
pump or neither pump might be running at any particular
time. The pump component dialog box is show below:
Figure 40
|
Property |
Description |
|
[pump_1] |
Unique identifier for this
component |
|
Cn = "" |
Comment line where n is an
integer >=1 |
|
QtyComments = n |
|
|
E_Pump_Rate=10 gpm |
Constant flow pump rate put out by
the electric pump when on |
|
E_Pump_On=2000 psi |
Pump low limit on switch |
|
E_Pump_Off=3000 psi |
Pump high limit off switch. |
|
A_Pump_Stall=3000 psi |
Pressure at outlet which will stall
the air driven pump (pressure at which its flow rate is
reduced to zero) |
|
A_Pump_Rate=4 gpm
|
Flow from the air driven pump with
no outlet pressure present. This is the absolute
maximum flow the air pump can manage. |
|
E_Pump_Init=on |
initial condition of the electric
pump |
|
A_Pump_Init=on |
initial condition of the air pump |
|
QtyOutputs=3 |
|
|
O1=Flow,y,gpm,-1 |
(Output) Total flow rate for both
pumps |
|
O2=E_Flow,n,gpm,-1
|
(Output) Electric pump flow rate |
|
O3=A_Flow,n,gpm,-1 |
(Output) Air pump flow rate |
The regulator component dialog box is
show below:
Figure 41
|
Property |
Description |
|
[regulator_1]
|
|
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