Aluminium silikon alloy merupakan paduan aluminium yang banyak digunakan dalam bidang teknik. Paduan ini memiliki kekuatan yang baik dan banyak diproduksi menjadi suatu komponen melalui proses pengecoran. Kandungan silikon dapat mengakibatkan penurunan fluiditas coran alumunium yang pada akhirnya akan menurunkan kualitas coran, fluiditas ini juga dipengaruhi temperatur pada saat penuangan alumunium cair. Penelitian ini bertujuan untuk mengetahui efek temperatur penuangan terhadap fluiditas, karakteristik aliran dan cacat coran pada pengecoran aluminium silikon alloy menggunakan cetakan pasir. Pengecoran dilakukan dengan gravity casting, analisa aliran simulasi meliputi distribusi kecepatan aliran, temperatur, tekanan, cacat permukaan dan fluiditas yang terjadi pada saat proses pengisian rongga cetak serta perbandingan fluiditas coran dan cacat permukaan pada eksperimental. Temperatur penuangan 685, 710, 735, 760 dan 785°C dengan ketebalan cetakan pola 1, 3, 5, 7, 9, dan 12 mm. Proses simulasi menggunakan software berbasis computational fluid dynamic. Hasil penelitian diperoleh temperatur tuang 785oC memiliki kecepatan aliran tertinggi yaitu sebesar ±0.145 m/s pada rongga 12 mm dan distribusi temperatur yang tinggi yaitu sebesar ±759 oC pada rongga 3 mm, sedangkan temperatur tuang 685oC memiliki distribusi tekanan yang tinggi yaitu sebesar ±107287 Pa pada rongga 6 mm. Cacat permukaan terbanyak pada temperatur tuang 785oC dan temperatur tuang 685oC paling sedikit. Fluiditas coran terbaik pada temperatur 785oC dimana rongga 12, 9, 7, 5 dan 3 mm terisi penuh dan 1 mm mencapai 181.4 mm.
Aluminum silicon alloy is an aluminum alloy that is widely used in engineering. This alloy has good strength and plenty of it are produced into a component through the casting process. Silicon content could result in a decrease in fluidity of aluminum castings which in turn would reduce the quality of casting. This fluidity is also influenced by temperature at the time of pouring liquid aluminum. This study aims to determine the effect of pouring temperature on fluidity, flow characteristics and casting defects on aluminum alloy silicon casting by using sand mold. Casting was conducted by gravity casting, simulation flow analysis including flow velocity distribution, temperature, pressure, surface and fluidity defects that occured during the process of filling the mold cavity as well as the comparison of the fluidity of castings and surface defects in the experiment. Casting temperatures was 685, 710, 735, 760 and 785°C with a mold thickness of patterns 1, 3, 5, 7, 9 and 12 mm. The simulation process used software based on computational fluid dynamic. The result showed pouring temperature of 785oC had the highest flow velocity of ± 0.145 m/s in 12 mm cavity and a high temperature distribution of ± 759oC in cavity of 3 mm, while the pouring temperature of 685oC had a high pressure distribution of ± 107287 Pa in 6 mm cavity. Most surface defects occurred at pour temperature of 785oC and the least at pour temperature of 685oC. The best castings liquidity occurred at temperature of 785oC where the cavity of 12, 9, 7, 5 and 3 mm was fully filled and 1 mm reached 181.4 mm.
Computational Fluid Dynamic Analysis of Flapping Wing of Micro Aerial Vehicle at Very Low Reynolds Numbers Turbulent Flow