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HGDT 0.5 online
Posted: Sun May 25, 2008 7:25 pm
by D_Hall
All new combustion model.
Improved heat transfer model.
Unfortuantely, new file format as well so it won't just load any previous files you may have made (that's the price for playing with betas!).
Posted: Sun May 25, 2008 8:53 pm
by Larda
One thing that i noticed is that you cant use a comma , you have to use a point when you enter the numbers.
What do you think of adding a ignition calculator, where you enter the electrode gap and it takes the pressure and number of gaps to calculate the voltage needed?
Posted: Sun May 25, 2008 9:11 pm
by D_Hall
Larda wrote:One thing that i noticed is that you cant use a comma , you have to use a point when you enter the numbers.
Blame Visual Basic. That's not something I've gotten my fingers messy with. Well, OK, in the past I tried to, but I think I did more harm than good so I've backed off and let VB handle all the parsing.
What do you think of adding a ignition calculator, where you enter the electrode gap and it takes the pressure and number of gaps to calculate the voltage needed?
Dunno. Never really thought about it before.
Posted: Sun May 25, 2008 9:25 pm
by Larda
D_Hall wrote:
Blame Visual Basic. That's not something I've gotten my fingers messy with. Well, OK, in the past I tried to, but I think I did more harm than good so I've backed off and let VB handle all the parsing.
Ok, then maybe you should change so the program doesn't use comma when you chose (cm) instead of (in).
If you want to add the ignition calculator here is the calculation:
Code: Select all
V = 4.3 + 136 × (p / T) + 324 × (p / T) × Dg
# V = voltage potential (kV)
# p = absolute pressure in Bar
# T = gas temperature (Kelvin)
# Dg = electrode gap in mm
Posted: Sun May 25, 2008 9:37 pm
by D_Hall
Larda wrote:Ok, then maybe you should change so the program doesn't use comma when you chose (cm) instead of (in).
Huh?
Is it changing? If so, I have absolutely ZERO idea what is going on. I've NEVER tried to change such things midstream.
If you want to add the ignition calculator here is the calculation:
Code: Select all
V = 4.3 + 136 × (p / T) + 324 × (p / T) × Dg
# V = voltage potential (kV)
# p = absolute pressure in Bar
# T = gas temperature (Kelvin)
# Dg = electrode gap in mm
Got an arc energy result in there somewhere? I mean, the arc will HAVE to have a certain energy density to result in ignition. If it's gonna be done, it might as well be done right.
Posted: Sun May 25, 2008 10:02 pm
by Larda
Huh?
Is it changing? If so, I have absolutely ZERO idea what is going on. I've NEVER tried to change such things midstream.
Here is a few screenshots.
The first is when i start the program, then i change it all to metric , after that i can remove all the decimals without affecting the result.
Got an arc energy result in there somewhere? I mean, the arc will HAVE to have a certain energy density to result in ignition. If it's gonna be done, it might as well be done right.
I found some numbers here, locks like the minimum ignition energy for propane/air is 0,26mj
http://yarchive.net/chem/ignition_energy.html
Edit: I haven't found how the energy needed for ignition is affected by the pressure yet.
Posted: Sun May 25, 2008 10:33 pm
by D_Hall
OK, based on the progression of screen shots it looks like....
1) Since you live overseas, you've got your computer set up to do the whole comma thing (where we use periods).
2) In some initialization stuff I assign some text values to some blocks. Those values are being inserted with periods (ie, as text, just the way I specified).
3) VB tries to deal with commas, but since there are some periods showing up... Well, perhaps some things are getting screwed up.
So what I've done: I just went in and reassigned some of those text blocks as numerical inputs. There's some type conversions and such... In any event, I've compiled a new version and uploaded it to the site. NOT in the .zip file, mind you. JUST in the "updated executable" location.
Can you give it a whirl and see what it does?
Posted: Sun May 25, 2008 10:47 pm
by Larda
Doesn't work at all.
Posted: Sun May 25, 2008 11:01 pm
by D_Hall
WTF?
For it not to have made any difference, I could have seen that. But to cause a crash? I'm totally confused.
Posted: Sun May 25, 2008 11:06 pm
by D_Hall
OK, another version uploaded to the executable location.
Give it a whirl?
Posted: Sun May 25, 2008 11:15 pm
by Larda
Same problem now.
Posted: Sun May 25, 2008 11:34 pm
by D_Hall
Where are you?
More to the point: What are the region settings on your computer?
edit: OK, for some reason I had imagined you in Sweden and set my region settings to that. Guess what? I can reproduce the error! Woohoo!
Posted: Sun May 25, 2008 11:47 pm
by Larda
Yes, i'am from Sweden.
Posted: Mon May 26, 2008 12:01 am
by D_Hall
Good news: I know what the problem is.
Bad news: I'm not sure how to fix it without potentially causing other problems.
What's happening... Visual Basic is screwing up. When it sees "0,05" it stops at the comma. It just sees the leading 0. Result? Division by 0.
Posted: Mon May 26, 2008 12:29 am
by starman
D_Hall wrote:Good news: I know what the problem is.
Bad news: I'm not sure how to fix it without potentially causing other problems.
What's happening... Visual Basic is screwing up. When it sees "0,05" it stops at the comma. It just sees the leading 0. Result? Division by 0.
Isn't there a way to make VB recognize and use the regional settings within Windows for its decimal style? I would think so, but if not, you may have to just do some string checking in the fields for commas before the calculation and accommodate from there.
Edit: Sorry, looks like you are all over the regional settings thing.