# Heat Convection through a Vertical Pipe

• AstroWave
In summary, the conversation discusses the topic of modeling steam flow through a vertical cylinder and finding the surface temperature as a function of length. The speaker is seeking advice on handling the convection term in the energy balance and is unsure about the fluid motion within the shell. They mention a similar process done for a solid pipe and ask for clarification on the concept and other possible approaches. The article provided is suggested for further reading.
AstroWave
Hello everyone,

I am trying to model the flow of steam through a vertical cylinder. Ultimately I would like to find the surface temperature as a function of the length of the pipe. I am assuming the steam cools as it moves upward along the length of the pipe and it is a steady-state process, so T only varies with position (1-dimensional).

Doing a shell balance around a small portion of the pipe I am confused about the convection term entering in from the base and leaving through the top of the shell. I understand the cross sectional area concerning this convection term is the area of a circle. However, I am uncertain about how to determine the gradient for the surface temperature when all of the terms in the energy balance are due to convection.

I have seen the similar process done for a solid pipe (long fin) where there was conduction through the shell and convection out of the side. But I am confused by fluid motion inside the shell.

Any advice on this conceptually, or if you could recommend another approach, would be appreciated.

You have to determine whether you are dealing with laminar or turbulent flow to begin with. The analysis is not a plug into an equation and get the answer,

http://people.msoe.edu/~kumpaty/courses/ME%20318/Week6_7.pdf

Last edited by a moderator:

## 1. How does heat convection occur through a vertical pipe?

Heat convection through a vertical pipe occurs when a fluid (such as air or water) is heated at the bottom of the pipe, causing it to rise and create a flow. This flow then transfers heat from the bottom of the pipe to the top, creating a convection current.

## 2. What factors affect the rate of heat convection through a vertical pipe?

The rate of heat convection through a vertical pipe is affected by several factors, including the temperature difference between the fluid and the pipe, the properties of the fluid (such as density and viscosity), and the diameter and length of the pipe.

## 3. How is heat convection through a vertical pipe different from heat conduction?

Heat convection through a vertical pipe differs from heat conduction in that convection involves the movement of a fluid, while conduction involves the transfer of heat through a solid material. Convection is generally a more efficient method of heat transfer, as it allows for a larger surface area to be in contact with the heat source.

## 4. Can the direction of heat convection in a vertical pipe be reversed?

Yes, the direction of heat convection in a vertical pipe can be reversed by changing the temperature difference between the fluid and the pipe. When the bottom of the pipe is cooler than the top, the fluid will sink and create a downward convection current.

## 5. How is heat convection through a vertical pipe used in practical applications?

Heat convection through a vertical pipe is used in many practical applications, such as heating and cooling systems, heat exchangers, and industrial processes. It is also an important factor in natural phenomena, such as ocean currents and atmospheric circulation. Understanding heat convection is crucial in designing efficient and effective systems for transferring heat.

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