How to choose the corresponding finned tube type under different working conditions?
How to choose the corresponding finned tube type under different working conditions? The following is a sharing from finned tube heat exchanger/radiator manufacturer. There are several principles for selecting finned tubes in different situations:
(1) If the heat transfer coefficients on both sides of the tube differ significantly, fins should be installed on the side with the lower heat transfer coefficient.
Example 1: Boiler economizer, water flows inside the tube, flue gas flows outside the tube; fins should be used on the flue gas side.
Example 2: Air cooler, liquid flows inside the tube, air flows outside the tube; fins should be added on the air side.
Example 3: Steam generator, water boils inside the tube, flue gas flows outside the tube; fins should be added on the flue gas side.
It should be noted that in the design, the side with the lower heat transfer coefficient should be placed outside the tube as much as possible for easy installation of fins.
(2) If the heat transfer coefficients on both sides of the tube are both low, to enhance heat transfer, fins should be installed on both sides simultaneously. If there are structural difficulties, fins can be omitted on both sides. In this case, adding fins on only one side will not significantly increase the heat transfer.
Example 1: Traditional tubular air preheater, air flows inside the tube, flue gas flows outside the tube. Because it is gas-to-gas heat transfer, the heat transfer coefficients on both sides are low, and adding fins inside the tube is difficult, so bare tubes are used.
Example 2: Heat pipe air preheater, although it still heats air with flue gas, because both flue gas and air flow outside the tube, fins can be conveniently used on both the flue gas side and the air side, greatly increasing the heat transfer.
(3) If the heat transfer coefficients on both sides of the tube are high, there is no need to use finned tubes.
Example 1: Water-to-water heat exchanger, heating cold water with hot water; the heat transfer coefficients on both sides are sufficiently high, so there is no need to use finned tubes. However, to further enhance heat transfer, threaded tubes or corrugated tubes can be used instead of bare tubes.
Example 2: Power plant condenser, water vapor condenses outside the tube, water flows inside the tube. The heat transfer coefficients on both sides are high; generally, there is no need to use finned tubes.
Finned tube type |
