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From: Zen Cycle <funkmaster@hotmail.com>
Newsgroups: rec.bicycles.tech
Subject: Re: Bicycle physics question
Date: Tue, 25 Jun 2024 11:57:22 -0400
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On 6/25/2024 11:24 AM, Jeff Liebermann wrote:
> On Tue, 25 Jun 2024 15:01:29 GMT, Tom Kunich <cyclintom@yahoo.com>
> wrote:
> 
>> On Tue Jun 25 09:02:14 2024 Zen Cycle  wrote:
>>> On 6/24/2024 8:41 PM, Frank Krygowski wrote:
>>>> On 6/24/2024 12:19 PM, Tom Kunich wrote:
>>>>>
>>>>> A mechanical engineer designs and constructs mechanisms.
>>>>
>>>> Wow. Such simplistic ignorance! But then, how would you know?
>>>>
>>>> Read at least a little bit about the field:
>>>> https://www.mtu.edu/mechanical/engineering/
>>>>
>>>>
>>>>
>>>
>>> Our lead ME just completed a CFD analysis for some different valve
>>> designs we're considering for a vapor recovery solution to be used at
>>> fuel depots. I'd say that's a bit more complex than 'designs and
>>> constructs mechanisms'.
>>> -- 
>>> Add xx to reply
> 
>> And again Dopey shows that he cannot read or understand the English language.
> 
> And once again, Tom demonstrates that he is overly simplistic,
> technically ignorant, out of touch with the latest technology and is
> unwilling to lookup an acronym with Google or DuckDuckGo search.  The
> following might help:
> 
> ME = Mechanical Engineer
> <https://en.wikipedia.org/wiki/Mechanical_engineering>
> 
> CFD = Computational Fluid Dynamics
> <https://en.wikipedia.org/wiki/Computational_fluid_dynamics>
> I'll admit that I know very little about CFD, but at least I'm still
> learning.
> 
> Vapor Recovery
> <https://ww2.arb.ca.gov/our-work/programs/vapor-recovery>
> 
> Mechanical Engineers that work in the machine design field usually
> don't build what they design (unless it's a model).  It's easier,
> faster and less messy to run a computer simulation.  Even with 3D
> Modeling, it's done by someone else.
> <https://www.google.com/search?q=mechanical+engineering+simulation+software&tbm=isch>
> 
> For bicycles, that would be FEA (Finite Element Analysis):
> <https://www.sheldonbrown.com/rinard/fea.htm>
> 
> "Bike Frame Structural Analysis with FEA"  (46:52)
> <https://www.youtube.com/watch?v=Uk9Nu3Wuh3s>
> 
> BikeCAD:
> <https://www.bikecad.ca>

Correct Jeff.

The fluid dynamic simulation is critical before we pull the trigger on 
molds that run in the $70K to $100K range. The fuel compartments are 
filled at up to 1000 GPM, and in many depots 2-3 compartments are filled 
at the same time, but only one vapor recovery plenum is mounted on the 
truck. This means that the vapor recovery coupler needs to be able to 
handle the equivalent of 3000 vapor gallons/min though a 4" pipe 
obstructed by a valve mechanism. There is a 'positive' vacuum in the 
system, but that's only to ensure no venting during the 
coupling/uncoupling process.

Since vapor is compressible, this has implications of pressure buildup 
on the installed vapor recovery piping and the the pressure relief 
valves. Can't have the relief valves 'burping' - they are monitored and 
over pressure conditions will set off alarms in the system.



-- 
Add xx to reply