Oval Tube Type Air-cooled Oil Cooler For Transformers
Oval Tube Type Air-cooled Oil Cooler for Transformers
Core advantages (compared with round tube)
Improved heat transfer efficiency
Increased air-side heat transfer area: For the same tube diameter (meaning equal cross-sectional area), oval tubes have a longer circumference than round tubes, allowing for more fins to be welded, and an increase in air-side heat transfer area per unit length of 15-30% (e.g., for an oval tube with a cross-sectional area of 100mm², the circumference is approximately 20% longer than a round tube of the same area).
Enhanced air turbulence: the long, flat cross-section of the oval tube creates more pronounced turbulence in the air flowing through the fins (especially in the "edge" areas at the ends of the tube's long axis), destroying the boundary layer, reducing thermal resistance and allowing for a faster transfer of heat from the tube wall to the air.
Optimization of oil-side flow: transformer oil in the oval tube flow, due to the asymmetric cross-section, easy to form spiral secondary flow, to avoid the common "center of low flow velocity, wall flow velocity is high" phenomenon of stratification in the circular tube, so that the oil flow and the wall contact more fully, to enhance the efficiency of the oil side of the heat transfer.
Reduce the space occupation
Reduce the windward area: the short axis direction of the elliptical tube can be parallel to the air flow direction, in the same heat dissipation power, its overall thickness (the size of the air flow direction) is smaller than the circular tube, suitable for transformer compartment, outdoor compact installation, and other space-constrained scenarios. For example, for the same number of coolers, the oval tube design can reduce the overall volume by 10-20%.
Advantage of Compact Arrangement: The flat structure of elliptical tubes allows for a denser arrangement of tubes (the spacing in the short axis direction can be reduced), which allows for more heat exchanger tubes to be arranged in a limited frame, thus increasing the heat dissipation capacity per unit volume.
Enhanced Structural Stability
Better Vibration Resistance: The elliptical tube has a higher stiffness in the long axis direction than the round tube, so it is not easy to resonate or deform in the airflow impact generated by the fan or in the vibration environment of the transformer operation, thus prolonging the service life of the tubes.
Stronger bonding of fins: Longer welding/expansion contact lines between the oval tube and fins result in stronger bonding, which reduces the problem of fins falling off due to long-term thermal expansion and contraction (especially in high temperature thermal oil circulation scenarios).
