Non Math Person needs help again

shellsie · 2012-01-25 20:18:44

So, here I am again with an equation that I just have no idea about. Obviously I am not a Maths person. I am doing a fire report for our trout farm in Australia and I thought rather than pay someone $5,000 to do the report I would give it a go.
The first part was easy, but now it's a bit hard going (that is an understatement)
So here goes:

E = a s c

c is to the power of 4 also.

a= Stefan-Boltzman constant
s= .95
c=1090

I am having trouble putting in the correct symbols so I just made up the formula

I am WAY out of my depth here as I know what the Stefan-Boltzman is (but don't know how to write the symbols within this message box).

Obviously do not know what E is but the answer that I will hopefully get will give me the radiant heat flux of fire.

Any help is MOST appreciated and if you are ever in Australia you must drop in to our trout/salmon farm and catch a fish for free.
Shellie

bobbym · 2012-01-26 02:14:59

The Stefan-Boltzman constant is 5.670373 * 10^(-8). I have left out the units because you have not told me in what units the other numbers are in.

When you say 1095, I have to say1095 what? Miles, feet, degrees, amperes, seconds, grams...

Is r the universal gas constant, or Rydbergs? They are both capital R. Can you copy the problem exactly as it appears? That would help and do not forget to leave nothing out.

I intend to visit Australia.

shellsie · 2012-01-26 13:39:13

B.10.2 Flame Emissive Power
Flame emissive power (E) shall be calculated using the Stefan-Boltzmann equation, as follows:

E= σ T_f^4

σ=Stefan Boltzman constant (5.67 x 〖10〗^(-11)kWm^(-2) K^(-4))
= flame emissivity (assumes 0.95)
T_f=flame temperature

I know that T_f is 1090K but that is all I know.
I have written it as I see it. Finally worked out I could do the maths symbols in Word....duh!
So what do you reckon, is there enough information? I should have listened more at high school but it was the same old story....I used to think when will I ever need to use all of this stuff!!!!
Thanks so much for your reply I really appreciate it.
Shell
ps I pasted this and all of the symbols did not turn out right. I originally tried to send a link that I had posted on Photobucket and Mathisfun (yeh right) server came back with "new users can not post links as they may contain spam." Not sure what to do now. AAARRRGGGHHH

bobbym · 2012-01-26 14:19:38

Hi;

This symbol did not post correctly but you want to call it .95.

Everything seems fine but what is

^(-11)kWm^(-2) K^(-4))

this little k in front of the W? It does not show up at Wikipedia. I know the capital K is Kelvins.

Anyway that is just a unit the answer appears to be.

We just need to know what that k is?

shellsie · 2012-01-26 14:41:37

Hello
I googled and came up with that kW/m means kilo Watts per metre. Which I guess means sense because it is to do with fire intensity?
So now do you come up with a final figure? Fingers crossed
Thanks again
Shell

bobbym · 2012-01-26 14:45:09

Hi;

Based on that Stefan Boltzman constant being 5.67 x10^(-11) as you have written, I am getting

shellsie · 2012-01-26 15:00:17

Sorry for my maths ignorance but is that as far as we can take the equation or do we end up with a single figure?
Shellie

bobbym · 2012-01-26 15:03:54

That is as far as we can go. The letters are units, like mph. When you say 60 mph the units tell you what the 60 means. Same thing here. If the .95 is correct and the SB constant is right then it was just a straight multiply. That is the answer.

shellsie · 2012-01-26 15:17:51

Thanks so much for your help and your time.
Not sure actually if I can take it any further as I thought that we would end up with a single figure.
The reason I thought this was because I then have to use the figure that I got to work out another equation. I thought I would have ended up with E (flame emissive power) as a single figure in kW/m to the power of 2.
Oh well, obviously it's me not you and I guess I will have to call it quits....but thanks, you've been great.
Shellie

bobbym · 2012-01-26 15:25:45

Hi Shellie;

You mean a whole number like 256? It is not likely with that constant in the equation.

shellsie · 2012-01-26 15:29:08

Hi
Yes a whole number..but if it's not possible then maybe I misunderstand the final result that I need?
Very frustrating

bobbym · 2012-01-26 15:36:35

The SB constant is a very small number. It really looks like this .000 000 000 056 7. You would have have some value in that equation that was huge to get a whole number.

shellsie · 2012-01-26 15:47:49

Ok, wow, you guys are smart!
I think that I will just use the simplified method for my report rather than struggling with this anymore. Thank you from the bottom of my heart for your time and look us up when you are in Australia at Trentham Trout Farm.
Shellie

bobbym · 2012-01-26 16:10:56

Not that smart. I do a lot of good guessing. Save me some fish!

Math Is Fun Forum

#1 2012-01-25 20:18:44

Non Math Person needs help again

#2 2012-01-26 02:14:59

Re: Non Math Person needs help again

#3 2012-01-26 13:39:13

Re: Non Math Person needs help again

#4 2012-01-26 14:19:38

Re: Non Math Person needs help again

#5 2012-01-26 14:41:37

Re: Non Math Person needs help again

#6 2012-01-26 14:45:09

Re: Non Math Person needs help again

#7 2012-01-26 15:00:17

Re: Non Math Person needs help again

#8 2012-01-26 15:03:54

Re: Non Math Person needs help again

#9 2012-01-26 15:17:51

Re: Non Math Person needs help again

#10 2012-01-26 15:25:45

Re: Non Math Person needs help again

#11 2012-01-26 15:29:08

Re: Non Math Person needs help again

#12 2012-01-26 15:36:35

Re: Non Math Person needs help again

#13 2012-01-26 15:47:49

Re: Non Math Person needs help again

#14 2012-01-26 16:10:56

Re: Non Math Person needs help again

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