Temperature of Nitrogen in a Pipe

[daz18983]

Hi, i am on work experience and they have given me a short task which is sort of the next step up from work i have done previously. Can anyone help me with the following:-

Vessel containing nitrogen at 50 ^oC

Nitrogen is pumped along a 30m length of pipe at a flow rate of 1.5 litres per minute

pipe line is at ambient temp 20 ^oC

I need to find the temperature of the Nitrogen upon it reaching the end of the pipe at 30m

I have calculated and gathered the following info -

pipe OD - 0.00635m
pipe ID - 0.00457m
Specific Heat Ration of Nitrogen (k) - 1.4
Absolute Preesure through pipe - 9bar
Density of nitrogen at 9bar - 9.47748 kg/m³

I'm not exactly sure how to start this?? But i have looked through some books and believe i need to work out the velocity first?? Any help would be greatly appreciated.

 

[daz18983]

Please ignore this post and refer to the later post on 01/07/2008 named "Thermodynamics Change in Gas Temperature along pipe" which is an attempt at the question and should be a clearer.

Thanks

 

[piercas]

Hello, great job on gathering all the necessary information for this task! I can help you by providing some guidance on how to approach this problem.

First, you are correct in thinking that you need to calculate the velocity of the nitrogen in the pipe. This is because temperature and velocity are related in fluid dynamics, specifically through the concept of convective heat transfer.

To calculate the velocity, you can use the equation Q = V * A, where Q is the flow rate (1.5 liters per minute in this case), V is the velocity, and A is the cross-sectional area of the pipe (which you have already calculated using the pipe OD and ID).

Next, you can use the convective heat transfer equation Q = h * A * (T1 - T2), where Q is the heat transfer rate, h is the convective heat transfer coefficient, A is the surface area of the pipe, and T1 and T2 are the temperatures at the two ends of the pipe (50 oC at the vessel and the unknown temperature at the end of the pipe).

You can rearrange this equation to solve for T2, the temperature at the end of the pipe. To do this, you will need to calculate the convective heat transfer coefficient, which can be found in tables or calculated using empirical equations based on the flow conditions and properties of the fluid (in this case, nitrogen).

Once you have calculated T2, you will have the temperature of the nitrogen at the end of the pipe. Keep in mind that this is an approximation and there may be other factors that can affect the temperature, such as heat loss to the surroundings.

I hope this helps guide you in solving this problem. Good luck with your work experience!