How to calculate the heat transfer area of finned tubes

The calculation method of heat transfer area 

2. ribbed tubes (For example , steel tube and aluminum fin).

Original Title: Finned tube with fin length of 1860 mm, two bare ends is  30 mm and fin diameter is 25 mm,  thickness under fin is 0.5mm, tube wall thickness is 2 mm, fin pitch is  2.8 mm, fin thickness is  0.35 mm, fin diameter is  57mm , effective fin height is  15.5 mm.

What is the heat transfer area of finned tube?

Answer: The calculation of heat transfer area, generally in the cumulative and air exposed part can be divided into three parts.

First part is the surface area of the base tube( need to deduct the fin thickness)

Second part is fin tip (the cumulative effective surface area) 

Third part is area of the two side of fin surface.

Value of the three numbers are added together is the heat transfer area of the fin tube.

Example: according to the original problem (first calculate the unit area meter).

The fin  thickness is 0.35mm , the fin pitch  is 2.8mm , and the number of effective units is 357 pcs.

The effective length of the base surface is 0.875 meters, 3.14x0.026x0.875 1000-357x0.35 = = 0.071435

The top surface area of the fin is 357 x 0.35 = 0.125 m, and the outer diameter of the fin is 57 mm, which is 3.14 x 0.057 x 0.125 = 0.0223 725

The area of two positive and negative fins. It is the area of a large circle, minus the area of a small circle, multiplied by the number of times 2.

The known diameters are 0.057meter and 0.026 meter, respectively, and the radii are 0.0285 and 0.013, and 3.14x (0.0285x0.0285-0.013x0.013) x357x2 = 1.44214.

Cumulative results; 1.44214 + 0.0223725 + 0.071435 = 1.536m2/ M.

The effective length is 1800, so the heat area of the finned tube is 2.765 square / pc.