## Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

## Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

(OP)

I have a transient pipe model (internal flow of water inside the pipe) that can calculate the water temperature distribution through the pipe length over time (solving convection-diffusion equation with heat sink).

This pipe model considers the heat transfer (as loss from the water to the surrounding ground) at turbulent and laminar flow conditions (using Gnielinski correlation, and Mills correlation to obtain the water thermal resistance, respectively).

“In life, the truest guide is science” – Mustafa Kemal Atatürk

This pipe model considers the heat transfer (as loss from the water to the surrounding ground) at turbulent and laminar flow conditions (using Gnielinski correlation, and Mills correlation to obtain the water thermal resistance, respectively).

**My Question:**How can I calculate the water thermal resistance when there is no flow condition?“In life, the truest guide is science” – Mustafa Kemal Atatürk

## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

TTFN (ta ta for now)

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## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

Also, what are you trying to actually determine. To get the average temperature of the water that isn't flowing, is a very basic heat transfer/resistance calculation that you wouldn't need a model for.

## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

I didn't understand well enough your question but the model shall answer zero velocity condition. I model district heating piping network so there are conditions (at spring and summer) that the end-users do not consume heat so the water content in the end pipes becomes zero-velocity so my model has to handle such conditions. If your question is if Mills correlation for laminar flow condition can be used for zero-flow condition: I must say that I don't know.

I consider the layers of the pipe sections so for water volume the pipe wall material is the heat sink while solving pure-diffusion equation with heat sink (this time the heat sink for the pipe wall material is the insulation material). I solve the numerical models for each of the layers (water, pipe wall, insulation, casing). So, yes, the sink temperature increases with time when the water temperature is increased).

It was my first attempt to just applying zero-flow (then Mills correlation was used to find the water-resistance as partial in the overall thermal resistance (water,steel,insulation,casing,ground). It works but the problem is that I have no idea what the water resistance is when at natural convection (at zero flow) exists. So I have doubt in the validity of the results obtained.

I don't have this handbook. But laminar flow?

“In life, the truest guide is science” – Mustafa Kemal Atatürk

## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

“In life, the truest guide is science” – Mustafa Kemal Atatürk

## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

_{Gr}as low as 0.10.## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition

## RE: Heat Loss from a Buried Pipe | Stagnant/No Flow Condition