Abstract
Different parameters of the circular-arc, trapezoidal and equal cross-section-shaped flow channels were analyzed, and the core volume goodness factor was used for the comparison of the three different types of flow channels. During the experiment, the Reynolds number (Re) on the air side ranged from 1200 to 5100. The results showed that the overall heat transfer performance of the three channels in this paper are circular-arc, trapezoidal and equal cross-section in order from good to bad. The overall heat transfer enhancement performance of the circular-arc flow channel is the best, which is 9–26.2% and 3.6–11.8% higher than that of the equal and trapezoidal cross-section flow channels, respectively. This showed that although the divergent flow channel structure reduces the fluid velocity in the flow process, it weakens the convective heat transfer performance in the flow channel. However, this gradually decreasing cross-sectional area improves the downstream heat transfer area and reduces the pressure drop in the flow process, thus promoting the overall heat transfer performance. With the increase in the circular radius (R), both the j and f factors increase, and the highest overall heat transfer performance is obtained at R = 300 mm. The convective heat transfer coefficient increases with the decrease in the inlet height.
Highlights
The equal cross-section flow channel heat exchange surface is widely used in plate-fin heat exchangers due to its advantages of a simple structure and low cost [1,2,3]
(2) The increase in the flow rate of the cooling medium increases the pressure drop (∆P), which increases in the form of a parabola as the flow rate increases
The results showed that when the slope angle (β) in the trapezoidal flow channel was between 0◦ and 40◦, the overall heat transfer performance of the trapezoidal flow channel was better than that of the equal cross-section flow channel
Summary
The equal cross-section flow channel heat exchange surface is widely used in plate-fin heat exchangers due to its advantages of a simple structure and low cost [1,2,3]. The structure of this conventional equal-section flow channel has many defects: (1) The temperature difference at the inlet is large, and the temperature difference at the outlet becomes small during the flow of the cooling medium, which limits the convective heat transfer capacity at the outlet region. In previous research [4,5], the heat transfer performance of the trapezoidal flow channel was mainly studied. The results showed that when the slope angle (β) in the trapezoidal flow channel was between 0◦ and 40◦ , the overall heat transfer performance of the trapezoidal flow channel was better than that of the equal cross-section flow channel
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