×
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

2 direction heat transfer

2 direction heat transfer

2 direction heat transfer

(OP)
hi, I have a metal heater which is contact with water and air (Metal heater is kind of plate). The metal heater energy supplied from external heat source or it is connected with power supply to produce resistance.
In that case, how I calculate total heat transfer? I am confused because heater will supplied to right and left.

RE: 2 direction heat transfer

The devil is in the detail on this one. If your plate is thick enough that you have a uniform temperature across the surface then heat load will be a combination of the heat transfer from the water and the air. If these are simple convection currents or if there is a flow in one or the other will make a huge difference as will the relevant masses and heat transfer actually going on.

If the temperature of the plate block is < 27C then you've got heat transfer from the air to the plate to the water complicating life.

It's likely that the heat transfer to the water far exceeds that to the air to the extent you might just allow for it by a few percent additional heat transfer.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: 2 direction heat transfer

(OP)
Hi,
Thank you for your responds and sorry for unclear message.

So, I want to use a metal heater (I want to set the heater constant which is 70oC) to heat water in a closed system. However, this closed system consists of still / stagnant water, metal heater, and air.

Due to the purpose of a metal heater is to heat the still water. So I there will be a heat loss in air part.

Because of that, I want to calculate heat loss and supply energy needed of the metal heater (It will be supplied from electricity).

However, so far I know the heat transfer calculation has gradually temperature gradient.

Thank you

RE: 2 direction heat transfer

(OP)
I think the air space could reduce heat loss there.
Water volume: 6 cm3
It is stagnant water, so there will be no circulation speed.

RE: 2 direction heat transfer

I didn't understand your last attachment.

You have tow surfaces with a surface temp of 70C. Just calculate the heat loss into the water and into air.

Your possible issue is that the water will gradually heat up if it's a closed system so you have a transient analysis going on there.

Why not insulate the air side?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

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