Thread Subject: Hydraulic Pipeline

Hi all,

I don't know how to exactly parametrize the hydraulic pipeline block.
In case I have a pipe which is 5 Meters long and outlet is 2 meters above fluid-level, what is the "Aggregate equivalent length of local resistances" -

Thank you for your help
Cheers
Jerome

On Feb 9, 8:50 am, "Jerome " <j.s...@gmx.net> wrote:
> Hi all,
>
> I don't know how to exactly parametrize the hydraulic pipeline block.
> In case I have a pipe which is 5 Meters long and outlet is 2 meters above fluid-level, what is the "Aggregate equivalent length of local resistances" -
>
> Thank you for your help
> Cheers
> Jerome

I guess you're using Simulink, which I don't have.
I've done a fair bit of pipeline hydraulics outside of Simulink, but I
have no idea what "Aggregate equivalent length of local resistances"
means. It's gobbledygook.
I empathise with you.
Why not use 5 and see what happens?

"Jerome " <j.steg@gmx.net> wrote in message
news:hkpptt$cph$1@fred.mathworks.com...
> Hi all,
>
> I don't know how to exactly parametrize the hydraulic pipeline block.
> In case I have a pipe which is 5 Meters long and outlet is 2 meters above
> fluid-level, what is the "Aggregate equivalent length of local
> resistances" -
> Thank you for your help
> Cheers
> Jerome
>

Hi,

I assume you are referring to the hydraulic pipeline block in SimHydraulics:
http://www.mathworks.com/access/helpdesk/help/toolbox/physmod/hydro/ref/hydraulicpipeline.html

Have a look at the documentation:
"Aggregate equivalent length of local resistances

This parameter represents total equivalent length of all local resistances
associated with the pipe. You can account for the pressure loss caused by
local resistances, such as bends, fittings, armature, inlet/outlet losses,
and so on, by adding to the pipe geometrical length an aggregate equivalent
length of all the local resistances. This length is added to the geometrical
pipe length only for hydraulic resistance computation. The fluid volume
depends on pipe geometrical length only. The default value is 1 m."

If you want to negletct those effects, you can set it to 0 or some small
value.

HTH,

Arnaud

"Arnaud Miege" <arnaud.miege@nospam.mathworks.co.uk> wrote in message <hkrb1m$cm2$1@fred.mathworks.com>...
>
> "Jerome " <j.steg@gmx.net> wrote in message
> news:hkpptt$cph$1@fred.mathworks.com...
> > Hi all,
> >
> > I don't know how to exactly parametrize the hydraulic pipeline block.
> > In case I have a pipe which is 5 Meters long and outlet is 2 meters above
> > fluid-level, what is the "Aggregate equivalent length of local
> > resistances" -
> > Thank you for your help
> > Cheers
> > Jerome
> >
>
> Hi,
>
> I assume you are referring to the hydraulic pipeline block in SimHydraulics:
> http://www.mathworks.com/access/helpdesk/help/toolbox/physmod/hydro/ref/hydraulicpipeline.html
>
> Have a look at the documentation:
> "Aggregate equivalent length of local resistances
>
> This parameter represents total equivalent length of all local resistances
> associated with the pipe. You can account for the pressure loss caused by
> local resistances, such as bends, fittings, armature, inlet/outlet losses,
> and so on, by adding to the pipe geometrical length an aggregate equivalent
> length of all the local resistances. This length is added to the geometrical
> pipe length only for hydraulic resistance computation. The fluid volume
> depends on pipe geometrical length only. The default value is 1 m."
>
> If you want to negletct those effects, you can set it to 0 or some small
> value.
>
> HTH,
>
> Arnaud
>
Hi Arnaud,
thanks for your prompt response.
Exactely that is the block I'm refering to.
In my assumption I only want to account for a height difference between inlet(Tank level) and outlet of 2 Meters. no other losses such as mentioned.
Is there a formula with which I can calculate the Aggregate equivalent length of local resistances" (L_eq)
Cheers,
Jerome

"Jerome " <j.steg@gmx.net> wrote in message
news:hkrdmq$2um$1@fred.mathworks.com...

>>
> Hi Arnaud,
> thanks for your prompt response.
> Exactely that is the block I'm refering to.
> In my assumption I only want to account for a height difference between
> inlet(Tank level) and outlet of 2 Meters. no other losses such as
> mentioned. Is there a formula with which I can calculate the Aggregate
> equivalent length of local resistances" (L_eq)
> Cheers,
> Jerome
>

Then I suggest you neglect this and set it to zero. Note however, that the
hydraulic pipeline block does not account for gravity effects (i.e. it
assumes that both extremities are at the same height). If you want to
include gravity effects, then you need to use the low-pressure version of
the block (available since R2009a):
http://www.mathworks.com/access/helpdesk/help/toolbox/physmod/hydro/ref/hydraulicpipelp.html

HTH,

Arnaud

"Arnaud Miege" <arnaud.miege@nospam.mathworks.co.uk> wrote in message <hkro4h$19f$1@fred.mathworks.com>...
>
> "Jerome " <j.steg@gmx.net> wrote in message
> news:hkrdmq$2um$1@fred.mathworks.com...
>
> >>
> > Hi Arnaud,
> > thanks for your prompt response.
> > Exactely that is the block I'm refering to.
> > In my assumption I only want to account for a height difference between
> > inlet(Tank level) and outlet of 2 Meters. no other losses such as
> > mentioned. Is there a formula with which I can calculate the Aggregate
> > equivalent length of local resistances" (L_eq)
> > Cheers,
> > Jerome
> >
>
> Then I suggest you neglect this and set it to zero. Note however, that the
> hydraulic pipeline block does not account for gravity effects (i.e. it
> assumes that both extremities are at the same height). If you want to
> include gravity effects, then you need to use the low-pressure version of
> the block (available since R2009a):
> http://www.mathworks.com/access/helpdesk/help/toolbox/physmod/hydro/ref/hydraulicpipelp.html
>
> HTH,
>
> Arnaud
>
Hi Arnaud,
Thx for your Help.

Jerome