The advantage of oval tube straight wing heat exchanger as dry surface cooling
At present, there are some problems in the conventional round tube heat exchanger technology.
(1) Wind resistance problem. When the wind speed of the heat exchanger is 2.5 m/s, the wind resistance of the six-row heat exchanger can reach 250 Pa. At this time, the energy consumption of the fan is large, and the wind resistance increases when the wind speed increases.
(2) Heat transfer problem. The heat transfer performance of round tube fin heat exchangers has reached the bottleneck. There are no effective measures at this stage. In order to increase the heat exchange capacity of the heat exchanger, only the heat dissipation can be increased, but at the same time, the volume of the heat exchanger must be increased. Increased costs.
When the elliptical tube technology is used in an electronic clean room, the air resistance of the FFU circulating air system can be greatly reduced and the energy consumption of the FFU system can be reduced due to the small wind resistance due to the windwardness.
At the same time, due to the special structure of the oval tube, the heat transfer coefficient of the heat exchanger can be increased.
The elliptical tube heat exchanger is an ordinary round copper tube with a diameter of 9.52 mm. After a special extrusion process, an elliptical tube with a growth axis of 12.5 mm and a short axis of 8 mm is produced.
At this point, if the two heat exchangers have the same tube center distance D, the tube spacing of the oval tube is dl, and the tube spacing of the circular tube is d2, it is obvious that d1>d2,d1-d2=2x(9.52-8)=3.04 Mm, oval tube can form a relatively large air flow.
For two heat exchangers with the same wind volume, under the same air volume condition, when the center distance of the same pipe is the same, the net flow between pipes can be increased by about 10%, the net and wind speed can be reduced, and at the same time, the wind speed can be effectively reduced. The turbulence on the lee side of the elliptical tube can be reduced by the above two factors.
High thermal conductivity
(1) The tube is extruded into an elliptical tube, and the tube increases slightly.
(2) At the same time, there is also a heat exchange wet period between the copper tube and the air fluid. Elliptical tubes have more heat transfer than circular tubes.
(3) The long axis of the elliptical tube also strengthens the degree of turbulence in the air on the wind side, improves the overall heat transfer effect, and increases the thermal conductivity coefficient K. The elliptical tube used in the heat exchanger can enhance the heat transfer results. The application of external reinforcement technology.
Under the heating conditions, the temperature distribution of the circular tube and the elliptical tube heat exchanger under the infrared camera clearly shows that the elliptical tube and the air flow heat exchange are more fully.