3 replies to this topic

[Engineers Are The Best]

I am nowadays designing a shell and tube heat echanger and the problem I am facing is that I want estimates of film coefficients for some common gases like ammonia,carbon di oxide,etc in the pressure range of 0.1-10kPa.

[Zauberberg]

Refer to any engineering textbook, such as Kern, Ludwig, GPSA etc. You have examples there. The ranges of U-values for your application should be somewhere in the range 5-40 W/m2C. Google this topic.

Check this link at ChE: U in heat exchangers

[Engineers Are The Best]

Thank you for giving me a small but good guide.

[Zauberberg]

Remember that the actual film coefficient will be the result of exchanger design you have chosen. The point is to select such exchanger type/geometry which will give you satisfactory heat transfer coefficient - the one you were targeting - and by taking into account all specific issues in the system you are dealing with.

Look also at this article by V. Ganapathy: Get heat transfer coefficient - Pressure effect on crossflow

If you cannot reach the references I mentioned in my previous post, let me know.