1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fire and ambient IR

  1. Feb 21, 2009 #1
    hello
    can someone tell me are ambient IR and IR in candle fire has different wave lengths?
    I'm trying to make a flame detector,so if there is different wave lengths i can use a filter circuit to filter only fire's IR signal.
    Thanks
     
  2. jcsd
  3. Feb 21, 2009 #2

    Mapes

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I think your best bet is to look at wavelengths around 1-2 um. According to Incropera and DeWitt's Fundamentals of Heat and Mass Transfer there's very little emission under 2 um for bodies at 300 K.
     
  4. Feb 21, 2009 #3
    well sir does candel fire emits IR around 1-2um? I'm not familier with physics laws you mentioned.
     
  5. Feb 21, 2009 #4

    Mapes

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    All materials emit all wavelengths, but there's a characteristic peak that's a function of temperature alone. For room temperature objects, it looks like the peak is around 10 um. For a candle flame, 1-4 um.
     
  6. Feb 21, 2009 #5

    uart

    User Avatar
    Science Advisor

    Yes, with a typical candle color temperature of about 2000k, by my calculations 2um should be reasonably close to the peak wavelength emitted.
     
  7. Feb 21, 2009 #6
    thankyou very much both of you sirs:smile:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Fire and ambient IR
  1. Cool down below ambient? (Replies: 13)

Loading...