2 replies to this topic

[vino]

Cold air flows through a circular duct of length 150 m at a temperature of 10 deg C.

Question: calculation of the heat transfer rate in the duct.

To calculate heat transfer rate, individual heat transfer coefficients values are needed.

For estimation of individual heat transfer coefficient, whether i can use dittus bolter equation or any other empirical equation is available for estimating inside and outside heat transfer coefficients.

[srfish]

I am not sure what you are asking. What is the situation outside the duct?

[ae.ng]

Two things:

1. You're going to need to clarify your question. Are you wondering about whether or not your empirical equation is suitable for the application? Or, are you unsure if you have to use another equation in solviing your problem?

2. I'm not sure if this is the right Forum to be posting in.

In any case, srfish is right in that you will need to know the situation outside the duct for making calculations. Also, more parameters including: your air velocity (flow regime)and your desired precision should be considered before you decide on the equation.