If diameter and length of a cylinder are 0.01 m and 0.07 m respectively, the thermal conductivity of air is 0.028 W/mK and the Nusselt number is 14.2, what will be the convective heat transfer coefficient

The convective heat transfer coefficient of the fluid is 170.4 watts per square meter-degree Celsius.

Explanation:

The Nusselt number () is a dimensionless factor which compares the sensitivity of a fluid due to convection with those due to conduction:

(Eq. 1)

Where:

- Convective heat transfer coefficient, measured in watts per square meter-degree Celsius.

- Conductive heat transfer coefficient, measured in watts per meter-degree Celsius.

- Characteristic length, measured in meters.

In addition, the characteristic length of a cylinder is defined by the following formula:

(Eq. 2)

Where:

- Radius of the cylinder, measured in meters.

- Length of the cylinder, measured in meters.

If we know that , , and , then the convective heat coefficient is:

From (Eq. 2):

And by (Eq. 1):

The convective heat transfer coefficient of the fluid is 170.4 watts per square meter-degree Celsius.

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