| 摘要 |
PURPOSE:To enable an entire uniform thermal passing rate to be attained and elongate a time until a space between fins is closed with frost during heating operation by a method wherein a pitch of fin is varied in more than two types and a fin pitch at an outlet side is made larger than a fin pitch at an inlet side of fluid within a thermal conducting pipe. CONSTITUTION:Fins 10a are arranged under a close fitting around a thermal conducting pipe 11a at an inflow-side of a coolant 12 (a low dried area of the coolant) and fins 10b are arranged under a rough fin pitch around a thermal conducting pipe 11b of a flowing-out part of coolant 12 (a high dried area of coolant). As viewed from outside of the thermal conducting pipe, as a result of a flow passage of air 13 between the fins 10a approaching to a rectangular shape, a thermal conductivity of air alphao has a high value. In turn, as viewed from an inside part of the thermal conducting pipe, an evaporation thermal conductivity alphai in a range of a degree of (x) of coolant of 0.5<=x<=0.9 shows a high value. Therefore, the fins 10a having a relative high alphao and the thermal conducting pipe 11a having a relative low alphai are combined with the fins 10b having a relative low alphao and the thermal conducting pipe 11b having a relative high alphai, resulting in producing an entire uniform thermal passing rate.
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