草稿整理 Build Direction Effects on Additively Manufactured Channels Snyder, J. C., Stimpson, C. K., Thole, K. A., and Mongillo, D. (January 20, 2016). "Build Direction Effects on Additively Manufactured Channels." ASME. J. Turbomach. May 2016; 138(5): 051006. https://doi.org/10.1115/1.4032168 Abstract 隨著直接金屬激光燒結 (DMLS)(通常也稱為增材製造 (AM))的進步,用於燃氣輪機冷卻的內部通道的新穎幾何特徵可以超越使用傳統製造技術的這些特徵。 然而,在 DMLS 過程中有許多變量會影響零件的最終質量。 燃氣輪機傳熱設計人員最感興趣的是內部通道可以保持的==粗糙度水平(roughness level)== 和 ==公差水平(tolerance levels)==。本研究調查了 DMLS 構建方向和通道形狀對小型通道的壓力損失和傳熱測量的影響。 結果表明,具有不同通道形狀和構建方向的測試案例之間會出現壓力損失差異,而==傳熱性能幾乎沒有變化==。 the goal of this study is to evaluate the effect of DMLS build direction on the pressure loss and heat transfer performance of small (mini) channels.
6/17/20210611025 郭庭均 金屬切削加工(metal machining) 金屬製品的的製造過程大致分為兩類,第一類是作為成型製造的鑄造、鍛造、焊接等等,而另一種則是加工製造,包含切削、磨削等。而金屬切削加工至今仍是最為基礎且重要的基本工藝之一。 金屬切削的種類繁多,有車削(Turning)、鉋切(Planing)、銑切(Milling)、鑽孔(Drilling)等等,其中切削理論的顧名思義就是將工件中多餘的金屬屑片(Chips)切除,使工件成為適當的尺寸與形狀。其中,切削工具的性能可以直接影響到切削加工的品質與生產效率。 切削顫振(chatter)的產生 切銷顫振的產生即是源於刀具的震動而引起的加工不穩定現象,會使得工件表面留下顫振的刀痕。如果刀具再次經過這些顫振刀痕,就會由於工件的不平整引起更大的震動,導致刀具造成更深的刀痕,惡性循環。如果工件的表面的粗糙度較大,可能會加速刀具磨耗,最終可能導致工件或刀具的損壞。 ▲ 顫振(參考連結)
6/7/2021Abstract 由於重力作用在laser sintering process過程中產上的熔體區域上,上方與下方的增材表面已顯示出不同的粗糙度特徵。 laser sintering process 1、2: scaled, structured-light scans of the upskin and downskin surfaces of an Inconel 718 component which was created at a 45° angle to the printing surface. [1] 3: similar to the Inconel 718 downskin surface, but a different scaling was used to provide larger roughness elements in the RIFT Roughness dimensions($R_q/D_h$) 0.0064(小)
5/31/2021Ch1 Introduction to Heat Transfer Introduction Energy can be transferred by interaction of a system with its surrounding, these interaction are called work and heat. Thermodynamics deals with the end states of the thermal interaction process, but provides no information concerning the nature of the interaction and the time rate at which it occurs. How much heat is transferred? How much work is done? Final/equilibrium staste of the system.
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