Woosung Choi

Mr. Woosung Choi

Pusan National University, Busan, Republic of Korea

Research Focus & Metrics

Academic Career Length

1Year (2026-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 October 2026 in Applied Sciences
Verified
Journal Article
Open access
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WCWoosung Choi
Woosung Choi
SLSeung Yeop Lee
Seung Yeop Lee
JSJi Hyun Sung
Ji Hyun Sung
SPSuk-Hee Park
Suk-Hee Park
KKKunwoo Kim
Kunwoo Kim
To address overhang sagging in laser powder bed fusion (L-PBF) of meso-scale film-cooling holes, this study proposes a 777TD hybrid geometry combining the nominal 7° diffuser features of a 777 hole with a pointed, self-supporting roof. Ideal smooth-wall computational fluid dynamics (CFD) calculations compared cylindrical, teardrop, 777, and 777TD holes with diameters of 0.5–0.8 mm at a blowing ratio of 1.0 and a density ratio of 1.5. At D = 0.8 mm, the predicted area-averaged adiabatic film-cooling effectiveness was 0.3308 for 777TD and 0.3208 for 777, a nominal relative increase of 3.1%. Separately, Haynes 230 specimens were fabricated at build orientations of 30° and 60° and evaluated by X-ray computed tomography (CT). At D = 0.8 mm and a 30° build orientation, the in-tolerance proportion in the selected outlet region was 93% for 777TD and 76% for 777, an increase of 17 percentage points under a ±0.1D deviation criterion. These results support further evaluation of the hybrid geometry for meso-scale cooling hole manufacture. The CFD comparison and CT conformity assessment provide complementary evidence; the cooling performance of the as-built holes has not been experimentally validated.