MapleSim Hydraulics Library from Modelon - MapleSim Help

Online Help

All Products    Maple    MapleSim


Home : Support : Online Help : MapleSim Toolboxes : MapleSim Hydraulics Library from Modelon : Volumes : ModelonHydraulics/Volumes/PistonGasAccumulator

MapleSim Hydraulics Library from Modelon

Piston Gas Accumulator  A gas filled piston accumulator

The gas model in the accumulator is based on the model from:

Span, R., Lemmon, E.W., Jacobsen, R.T, Wagner, W., and Yokozeki, A. "A Reference Equation of State for the Thermodynamic Properties of Nitrogen for Temperatures from 63.151 to 1000 K and Pressures to 2200 MPa," J. Phys. Chem. Ref. Data, 29(6):1361-1433, 2000.

The equation of state (EOS) has been compared to the implementation of REFPROP and gives the same results. This implementation covers only the 1-phase region. It is possible to choose a version that uses the corresponding ideal part only, but this is not recommended.

 

Variables

Connections

Parameters

Variables

Name

Value

Units

Description

Modelica ID

pistonCylinder

 

 

 

pistonCylinder

housing

 

 

 

housing

friction

 

 

 

friction

fixed

 

 

 

fixed

chamber

 

 

 

chamber

spring

 

 

Gas or mechanical spring

spring

Environment

 

 

 

Environment

pAsummary

chamber.p

Pa

Pressure at port A

summary_pA

qchamsummary

chamber.qcham

m3s

Flow rate flowing into Chamber

summary_qCham

Phydsummary

chamber.summary_HP

W

Hydraulic Power in chamber

summary_HP

Connections

Name

Description

Modelica ID

portA

 

port_A

Parameters

General Parameters

Name

Default

Units

Description

Modelica ID

nports

0

 

Number of ports

nPorts

di

 

m

Inner diameter of cylinder

d_i

Vdead

10-6

m3

Minimum oil volume

dead_volume

m

110

kg

Mass of piston

m

smax

12

m

Piston maximum stroke (between stiff, compliant cylinder walls)

s_max

piston

0.02

m

Length of piston

piston_length

sstart

12smax

m

Cylinder initial stroke: default is half full

s_start

ppreload

4.·107

Pa

Preload pressure for empty accumulator

p_preload

ΔTsystem

0

K

Temperature offset from system temperature

dT_system

Tstart

300

K

Initial gas Temperature

T_start

use time constant

true

 

If true, a time constant is used for the thermal behavior, otherwise a heat transfer law

use_time_constant

tthermal

60

s

Thermal time constant

t_thermal

α

150

Wm2K

Heat transfer coefficient

alpha

Tenv

298.15

K

Fixed environment temperature

T_env

initial filling

1

 

Initial filling of gas cylinder as fraction of total

initialFilling

Friction Parameters

Name

Default

Units

Description

Modelica ID

dviscous

4.·103

Nsm

 

viscous_damping

Constant Parameters

Name

Default

Units

Description

Modelica ID

Apiston

[1]

m2

Piston area

piston_area

Vstart

sstartApiston

m3

Oil volume at initialization

V_start

[1] 14di2π

See Also

Volumes

MapleSim Hydraulics Library from Modelon Overview

 


Download Help Document

Was this information helpful?



Please add your Comment (Optional)
E-mail Address (Optional)
What is ? This question helps us to combat spam