| 摘要 |
A turbine portion, for example a turbine blade, for exposure in a hot fluid flow includes at least one internal cooling passage disposed therein. A cooling fluid is introduced within the cooling passage(s) to maintain the bulk temperature of the turbine portion at some acceptable temperature level. A plurality of concavities are disposed on the interior surface of the cooling passage. In one embodiment, the concavities are formed on the interior surface of cooling passage in an array pattern such that a spiral bulk fluid motion is obtained, similar to that which would be formed by a helical rib, but without the rib. The concavity surface pattern serves to enhance heat transfer to the same degree as the conventional rib rougheners, but with significantly less pressure loss due to friction. The spiral motion of the bulk cooling fluid also serves to recirculate central coolant to the heat transfer surface, thereby making the heat exchange process more effective than that for turbulated surfaces.
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