Search found 329 matches

by JJG Koopmans
Sun Jan 14, 2018 8:03 am
Forum: Live Steam
Topic: Union Pacific Big Boy in 3/4 Inch Scale
Replies: 106
Views: 29600

Re: Union Pacific Big Boy in 3/4 Inch Scale

@Rwilliams,
Thanks for the orifice data!
kind regards
Jos Koopmans
by JJG Koopmans
Mon Jan 08, 2018 7:44 am
Forum: Live Steam
Topic: Union Pacific Big Boy in 3/4 Inch Scale
Replies: 106
Views: 29600

Re: Union Pacific Big Boy in 3/4 Inch Scale

Highly interesting, thanks! Could somebody let me know what the internal diameter of the 8 exhaust orifices is of the original (1:1) locomotive? My drawing does not have that detail, thanks!
Kind regards
Jos Koopmans
by JJG Koopmans
Sun Sep 24, 2017 2:08 pm
Forum: Live Steam
Topic: Help Identifying & Valuing Train
Replies: 45
Views: 4863

Re: Help Identifying & Valuing Train

To give an idea about a working one:
https://www.youtube.com/watch?v=J-fVTjv70tI
kind regards
Jos Koopmans
by JJG Koopmans
Fri Jun 02, 2017 9:27 am
Forum: Live Steam
Topic: Help plumbing a vertical injector
Replies: 6
Views: 1501

Re: Help plumbing a vertical injector

Question for the injector users. If one puts the injector to one's mouth and blow through it would one feel suction
at the water inlet???
Kind regards
Jos Koopmans
by JJG Koopmans
Thu Apr 13, 2017 3:47 am
Forum: Live Steam
Topic: Stack exhaust design revisited: the 1 in 6 taper myth?
Replies: 281
Views: 34095

Re: Stack exhaust design revisited: the 1 in 6 taper myth?

In my thesis of 2005 I devoted one and a half page to the effect of the Strouhal number which has exhaust beat frequency in it. At that time I noted already the research outside locomotives indicated increased performance with pulsation. My point of view is that in design and momentum calculations o...
by JJG Koopmans
Tue Apr 11, 2017 5:42 am
Forum: Live Steam
Topic: Stack exhaust design revisited: the 1 in 6 taper myth?
Replies: 281
Views: 34095

Re: Stack exhaust design revisited: the 1 in 6 taper myth?

1) using someone's 1898 opinion is not a strong argument in a scientific debate 2) just Googling "pulsating flow diffuser" will give a load of articles with conclusions like: ".....(2) The time-mean pressure rise is larger than that in the steady flow, ..." just meaning that in a steam locomotive a ...
by JJG Koopmans
Sun Jan 08, 2017 5:53 am
Forum: Live Steam
Topic: Stack exhaust design revisited: the 1 in 6 taper myth?
Replies: 281
Views: 34095

Re: Stack exhaust design revisited: the 1 in 6 taper myth?

(@Law)As far as the Adams vortex blastpipe is concerned, it consists of two blastpipes of which the orifices are flattened into a bananashape. As such it allows flow between the blastpipes. It was generally considered successful, however, being a casting it could not be repaired from wear as welding...
by JJG Koopmans
Wed Jan 04, 2017 10:26 am
Forum: Live Steam
Topic: Running a British Injector above its rated pressure?
Replies: 29
Views: 3407

Re: Running a British Injector above its rated pressure?

Fred, Hot water is a problem for any injector, even for the 1:1 locomotives. The problem being that steam contains a lot of heat and has to be totally condensed for any effect. So above a certain water temperature there is insufficient condensation and the device will not work. kind regards Jos Koop...
by JJG Koopmans
Wed Jan 04, 2017 5:18 am
Forum: Live Steam
Topic: Running a British Injector above its rated pressure?
Replies: 29
Views: 3407

Re: Running a British Injector above its rated pressure?

Howard Gorin wrote:In short an injector works on velocity, not pressure.......
That might suffice for the explanation, however, what is described is momentum,density times velocity squared
which has a dimension of a pressure!
kind regards
Jos Koopmans
by JJG Koopmans
Mon Aug 08, 2016 5:06 am
Forum: Live Steam
Topic: Hunslet draughting issues
Replies: 82
Views: 7916

Re: Hunslet draughting issues

Yeah, sorry!
Kind regards
Jos Koopmans
by JJG Koopmans
Sun Aug 07, 2016 7:03 am
Forum: Live Steam
Topic: Hunslet draughting issues
Replies: 82
Views: 7916

Re: Hunslet draughting issues

.... However, to suggest that 1:3-1:6 must be in fluid dynamics publications seems a bit of a stretch considering the design strategy is so unique to front end design....... Thanks, Bryce This is exactly your problem well defined, you do not wish to see a front end as a subsonic high volume ejector...
by JJG Koopmans
Sat Aug 06, 2016 5:17 am
Forum: Live Steam
Topic: Hunslet draughting issues
Replies: 82
Views: 7916

Re: Hunslet draughting issues

Bryce, Apparently you see it as your goal in life to totally misrepresent my ideas. I reserve the rights to myself only to explain my ideas about the functionality of textbook fluid dynamics in model steam locomotives. It is a free country, you are entitled to your ideas. However I am entitled to mi...