×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

insulating two ends of a rod with another

insulating two ends of a rod with another

insulating two ends of a rod with another

(OP)
Hallo,
I have an aluminium rod (crossection: 10mx10m and Length: 80 mm, heat capacity 0.9) placed inside a chamber of 100m3. The rod consists of three sections along its length (20mm sections on both ends and a 40mm section in the middle). All sections are of aluminium.
I want to find out the influence of heat sources present in chamber on the ends of the rod (or locations where ends present inside the chamber). Thus I mounted two temperature sensors on the surface of the both sections on both ends.
The readings of the sensors would not be precise representation of the temperature of the ends due to heat flow (conduction) through the middle section. The middle section is mandatory in my system design. My idea is to replace the middle section with a section of an insulating material (eg. plastic). Which material should I select? The goal is to disconnect the heat flow between ends without inducing any other factor of measurement uncertainty. What factors to consider (eg. heat capacity).
Thnaks
simon

RE: insulating two ends of a rod with another

At what temp?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: insulating two ends of a rod with another

Draw a sketch showing chamber, rod placement, location(s) of heat source(s) and any existing insulation beside the replacement of the inner rod with non conductive material. Also EdStainless' inquiry is legitimate due to temperature limitation with plastic.

RE: insulating two ends of a rod with another

You have only 20mm of aluminum, so why bother keeping that tiny bit conductive? Why not make the rod out of alumina?

For that matter, in a 100 m^3 chamber, why would you expect much temperature gradient over 0.04 m?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: insulating two ends of a rod with another

To me, 10m X10m x 20mm long would not be considered rods but merely plates.

RE: insulating two ends of a rod with another

It is hard to beat "nothing" as a non-conductive medium. What is the point of the portion in the middle - why not engineer it out of the picture?

RE: insulating two ends of a rod with another

(OP)
The middle section can’t be replaced by anything to maintain the configuration of the original system and holding the rod inside the chamber. The relative temperature of the area inside the camber where 2 ends are present can very within 15 min time upto 15 mK.
Does a plastic insulator ensure me complete insulation between the ends? What to consider about the heat capacity of the insulation?

RE: insulating two ends of a rod with another

As yet, you still have not given the temperature range; it's unclear whether the temperature in your figure is the operational temperature or just an arbitrary example.

Insulators tend to have low heat capacities as well, since their density tends to help with thermal resistance. If 15C is a realistic temperature, then pretty much any insulator will work.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: insulating two ends of a rod with another

So are still dealing with plates 10mX10mx10mm or are the dimensions 10mx10m incorrect? There is a big difference on the application of heat transfer equations between plates and rods.

RE: insulating two ends of a rod with another

(OP)
The dimention are: 10 mm x 10 mm in crossection and 100 mm in length. Where 100 mm length consist of three sections 10+80+10 mm. The middle sections should be made of an insulator.
The temperatute in chamber of mostly 15 C°+/- 0.1C° but it can also be 20 C°+/- 0.1C° in very few cases.
Should the heat capacity of the selected insulator should match the heat capacity of aluminium (orignal material) for high accuracy of the temperature measurements on ends? I am considering Teflon due to heat capacity close to the heat capacity of the Aluminium (?)

RE: insulating two ends of a rod with another

(OP)
I have to have two ends of Aluminium in the system and can only replace the middle part.
I guess many insulators materials would work for this application. Heat capacities may not be a worry.

RE: insulating two ends of a rod with another

Do a search of porcelain insulators. You may even be able to make you own kiln fired type.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close