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Vol.49, No.3, 221 ~ 231, 2011
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| Title |
| A Numerical Analysis of Flow Field in the Silt Nozzle During Cold Spray Coating Process |
| 박혜영 Hye Young Park , 박종인 Jong In Park , 정훈제 Hun Je Jung , 장경수 Kyoung Soo Jang , 백의현 Ui Hyun Baek , 한정환 Jeong Whan Han , 김형준 Hyung Jun Kim |
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| Abstract |
| The cold spray process is an emerging technology that utilizes high velocity metallic particles for surface coating. Metallic powder particles are injected into a converging-diverging de Laval nozzle and accelerated to a high velocity by a supersonic gas flow. The cold spray process normally uses a circular nozzle that has a rather narrow spraying range. To overcome this fault, a slit nozzle was considered in this study. The slit nozzle is anticipated to reduce the coating process time because it has a wider coating width than the circular nozzle. However, the slit nozzle can reduce the coating efficiency because it does not allow as much gas and particle velocity as the circular nozzle. To improve the coating efficiency of a slit nozzle, the shape of the slit nozzle was modified. And the results of gas flow and particle behaviour according to the nozzlers shape were compared by the a numerical analysis. As a results, as Expansion Ratio(ER) of 7.5 was found to be the most optimal condition for enhancing the spraying efficiency when the ER was changed by the variation of nozzle neck and exit size. |
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| Key Words |
| alloy, cold spraying, numerical simulation, slit nozzle, critical velocity |
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