Re: "Rockets not carrying fuel" for orbital transfer.

From: George Dishman (george_at_briar.demon.co.uk)
Date: 11/25/04 

Date: Thu, 25 Nov 2004 20:33:42 -0000

Much snipped to get to the physics, I understand
your concept.

"Robert Clark" <rgregoryclark@yahoo.com> wrote in message
news:832ea96d.0411201704.7de95ba@posting.google.com...
> | |
> | |
> |___ ___|
> /__ | | __\
> // || || \\
> //| |\\
> // | | \\
> | |
> | |
>
> [thrust] = (pressure)*(square area of ports)

I'm tied up with other things so I can't give this
much time but I think the thrust will be the pressure
difference through the nozzle times the flow rate.
You certainly need to take conservation of momentum
into account. Both flow rate and pressure difference
will depend on the nozzle design, and I think what is
good for one is bad for the other.

> Now remember the entire tubes weight is supported by these exhaust
> ports

The mass in the pipe is accelerating so you need more
thrust, and the acceleration means there is a pressure
difference between the top and bottom of the section
which will accumulate as you go down the pipe.

Finally, as flow is being lost at each section, the
flow rate at the bottom is more than at the top, and
the difference grows as the pipe adds more sections.

All of these factors complicate the maths significantly.

George

Relevant Pages

  • Re: "Rockets not carrying fuel" for orbital transfer.
    ... difference through the nozzle times the flow rate. ... Both flow rate and pressure difference ... The mass in the pipe is accelerating so you need more ... difference between the top and bottom of the section ...
    (sci.space.policy)
  • Re: "Rockets not carrying fuel" for orbital transfer.
    ... difference through the nozzle times the flow rate. ... Both flow rate and pressure difference ... The mass in the pipe is accelerating so you need more ... difference between the top and bottom of the section ...
    (sci.astro)
  • Re: Water pipe size
    ... My question is "will this create a pressure or flow rate ... Knowing how iron/galv pipe ages, its effective size is probably considerably ... since your plan is ultimately to replace all of the old ...
    (alt.home.repair)
  • Re: The things people build out of PVC nowadays...
    ... Isn't it very similar to a water tower? ... >thin pipe coming out of the bottom. ... the more pressure you get at the tap. ... a relatively low flow rate. ...
    (alt.sysadmin.recovery)
  • Re: Question about Poiseuilles formula.
    ... >>Poiseuille's formula calculates the volume fluid flow through a pipe ... >>given its viscosity and the pressure change at the two ends. ... >> My question concerns a vertical pipe with the fluid pumped upwards. ...
    (sci.physics)