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Fitroh, Ahmad Jamaludin
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RANCANG BANGUN ROTOR TURBIN ANGIN 10 KW UNTUK MEMPEROLEH DAYA OPTIMUM PADA VARIASI JUMLAH DAN DIAMETER SUDU Atmadi, Sulistyo; Fitroh, Ahmad Jamaludin
Indonesian Journal of Aerospace Vol. 7 No. 2 (2009): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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Penelitian ini merupakan bagian dari kegiatan penelitian untuk mendapatkan rancangan baru sudu rotor Turbin Angin 10 kW. Putaran rotor disesuaikan dengan putaran rancangan generator, yaitu 270 rpm. Pada kecepatan angin 10 m/det, rotor diharapkan mampu menghasilkan daya sekitar 12 kW. Penelitian dilakukan dengan memvariasikan jumlah sudu dan diameter rotor. Dengan menggunakan Computational Fluid Dynamic serta memperhitungkan pengaruh jumlah sudu dan diameter sudu, hasil perhitungan menunjukkan bahwa semakin banyak jumlah sudu, maka daya maksimum yang dapat dihasilkan rotor akan semakin kecil. Selain itu penambahan diameter rotor tidak selalu menghasilkan kenaikan daya. Pada jumlah sudu tertentu terdapat diameter optimal yang menghasilkan daya maksimum. Penelitian ini memberikan kesimpulan bahwa rotor akan menghasilkan daya lebih besar dari 12 kW bila menggunakan jumlah sudu sama dengan dua dengan diameter rotor antara 9,2 hingga 11,2 m.
ANALISIS LAPISAN BATAS ALIRAN DALAM NOSEL STUDI KASUS: NOSEL RX 122 Fitroh, Ahmad Jamaludin; Saeri
Indonesian Journal of Aerospace Vol. 7 No. 2 (2009): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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Telah dilakukan simulasi dan perhitungan lapisan batas permukaan dinding bagian dalam nosel. Studi kasusnya adalah nosel RX 122. Nosel mempunyai diameter inlet, throat, dan exit masing-masing 100, 34, dan 96 mm. Simulasi dan analisis lapisan batas dilakukan dengan kondisi batas tekanan dan temperatur ruang bakar masing - masing 59 bar dan 3.000 K. Hasil simulasi menunjukkan bahwa lapisan batas tetap terjadi mulai dari nosel bagian depan (up stream throat) hingga ke belakang (down stream throat). Lapisan batas semakin menebal pada posisi mendekati inlet dan exit. Tebal lapisan batas di dekat inlet dan di dekat exit masing-masing adalah 0,28dan 0,67 mm.
RANCANGAN DAN ANALISIS AERODINAMIKA SUDU TURBIN ANGIN KAPASITAS 300 KW Atmadi, Sulistyo; Fitroh, Ahmad Jamaludin
Indonesian Journal of Aerospace Vol. 6 No. 2 (2008): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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Penelitian ini merupakan bagian dari kegiatan Perancangan SKEA 300 kW. Rotor dirancang dengan diameter 45 m dengan jumlah sudu tiga buah. Penampang sudu berbentuk airfoil NACA 4424, 4418, dan 4412 berurutan dari pangkal hingga ujung. Prestasi airfoil dihitung dengan simulasi secara CFD dengan mempertimbangkan efek bilangan Reynolds dan bilangan Mach. Geometri sudu mempunyai puntiran sebesar 15º. Dengan memperhitungkan rugi-rugi antara rotor dan generator, maka sudu akan mampu menghasilkan 350 kW pada kecepatan angin nominal 10 m/det dengan sudut pasang sudu sebesar 2º pada putaran 35 rpm dan tip speed ratio λ = 8,24.
PENGEMBANGAN METODE PARAMETER AWAL ROTOR TURBIN ANGIN SUMBU VERTIKAL TIPE SAVONIUS Atmadi, Sulistyo; Fitroh, Ahmad Jamaludin
Indonesian Journal of Aerospace Vol. 6 No. 1 (2008): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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Telah dikembangkan metode penentuan parameter awal rotor turbin angin sumbu vertikal tipe Savonius. Dengan daya dan kecepatan angin tertentu, maka kisaran luas, diameter, tinggi, dan kecepatan putar rotor dapat diketahui. Luas rotor sangat dipengaruhi oleh koefisien daya, cP. Kecepatan putar rotor rancangan dapat dihitung setelah diameter rotor dihitung dan Tip Speed Ratio ditentukan. Penelitian ini menggunakan harga koefisien daya (cP), Tip Speed Ratio (TSR), dan rasio diameter terhadap tinggi rotor (D/t) masing – masing 0,1 ; 0,8 ; dan 0,8. Hasil metode ini berupa tabel daya, kecepatan angin, luas rotor, diameter, tinggi serta kecepatan putar, dapat digunakan sebagai rancangan awal turbin angin Savonius bagi para pemula maupun bagi yang awam tentang turbin angin namun ingin membuat, karena turbin angin Savonius dapat dibuat secara sederhana.
ANALISIS NOSEL MOTOR ROKET RX - 122 LAPAN SETELAH DILAKUKAN PEMOTONGAN PANJANG DAN DIAMETER Fitroh, Ahmad Jamaludin; Saeri
Indonesian Journal of Aerospace Vol. 6 No. 1 (2008): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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Telah dilakukan penelitian dan analisis ulang nosel motor roket RX - 122 milik LAPAN. Nosel tersebut didesain untuk tekanan ruang bakar 70 bar. Hasil perhitungan secara analitis menunjukkan bahwa gaya dorong yang dihasilkan seharusnya sebesar 18,6 kN. Hasil simulasi numerik memberikan gaya dorong yang lebih kecil, yaitu sebesar 18,0 kN. Perbedaan tersebut dikarenakan adanya gesekan antara aliran gas dengan permukaan bagian dalam nosel yang mana ditandai dengan penurunan tekanan total sebesar 13%. Diameter awal nosel adalah 130 mm. Oleh karena keterbatasan dimensi motor roket, maka diameter nosel harus dibatasi maksimum 100 mm. Pengurangan diameter nosel dilakukan dengan cara memotong nosel sepanjang 85 mm. Pemotongan tersebut mengakibatkan penurunan prestasi nosel. Perhitungan secara analitis dan simulasi numerik memberikan gaya dorong masing – masing 18,1 kN dan 17,7 kN. Akibat pemotongan panjang nosel tersebut, maka gaya dorong yang dihasilkan nosel berkurang hanya sekitar 2%.
SIMULASI CFD PADA DIFFUSER AUGMENTED WIND TURBINE (DAWT) : EFEK BENTUK INLET DAN PANJANG DIFUSER TERHADAP DISTRIBUSI KECEPATAN ANGIN DI EXIT DIFUSER Atmadi, Sulistyo; Fitroh, Ahmad Jamaludin
Indonesian Journal of Aerospace Vol. 10 No. 2 Desember (2012): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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The objective of the research is to obtain a lighter diffuser design. It is done by modifications previously designed diffuser on the shape and length of its inlet. Thus the study analyze the effect of modified inlet and diffuser length on the distribution of wind speeds at the nozzle exit. Analysis was performed using a CFD-based software. Modifications was made to the diffuser inlet and exit diameter each-amounting to 4 and 2 m. Modified inlet can improve performance by 1.4%; meanwhile the wind angle of 60º, the performance was reduced by 2.45%, due to the separation. Shortening the length diffuser can reduce the velocity distribution in the exit, maximum of occurs at length of 1 m at 4.6%. Therefore it is recommended that optimum diffuser length is 2 m.
PERHITUNGAN DAN ANALISIS LOSSES, DIAMETER EFEKTIF ROTOR, DAN PENYERAPAN DAYA DAN ENERGI PADA DIFFUSER AUGMENTED WIND TURBINE (DAWT) Atmadi, Sulistyo; Fitroh, Ahmad Jamaludin
Indonesian Journal of Aerospace Vol. 9 No. 2 Desember (2011): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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The use of diffuser in wind turbine (DAWT) is aimed at increasing the effective speed to produce a higher power. A bigger and heavier turbine results in difficulty in manufacturing the turbine orientation system. This research consists of three parts i.e. the calculation and analysis of the losses, determination of the effective diameter of the rotor, and the calculation and analysis of the absorbed energy by DAWT. The losses calculation and analysis is based on the friction between the airflow and wall. The diameter of the rotor is choosen in the diffuser area which has minimum turbulence flow produced by the wind angle. The calculation and analysis of the power is based on its rotor diameter. Then the power converted to become energy. In this research, DAWT is assumed to have no orientation system so that easily manufactured, i.e. the rotor is oriented at a single direction. Wind direction and frequency is selected in three configurations. In the first configuration, the wind direction comes from all the twelve wind source direction with the same frequency in the 24 hour period, producing 2 hourly periods for every wind direction. In the second configuration, wind from 90° and 270° or perpendicular to the axial turbine axes are eliminated, and hence producing 10 different wind directions at 2.4 hourly periods. In the third configuration, the turbine is set at the beach whereby the wind direction comes only at two direction; the sea and land wind directions. At these conditions, the wind is assumed to come at 0°, 30°, 150°, 180°, 210°, and 330°. The aim of this research is to calculate the energy absorption of the wind rotor, and comparing with those produced without the diffuser system in place. In this research, a 2m rotor diameter and 4m diffuser diameter is selected, power coefficient of 0.3, wind speed of 5m/sec, and these parameters are constant for the 24 period under analysis. The result of the calculation shows that there are losses near wall especially for high wind angle. The rotor diameter have chossen about 1,940 m. The energy absorption of the wind rotor without the diffuser is 6.231 kJ. The energy absorption values for the 1st, 2nd and 3rd configuration with the diffuser produce 54.361, 65.234, and 101.316 kJ respectively. It shows that the use of diffuser in the wind rotor could produce an increase of up to 9 to 16 times in the power absorption of the rotor.
PENGEMBANGAN METODE PENENTUAN KARAKTERISTIK RANCANGAN AWAL ROTOR TURBIN ANGIN Atmadi, Sulistyo; Fitroh, Ahmad Jamaludin
Indonesian Journal of Aerospace Vol. 5 No. 1 (2007): Vol 5, No.1 Juni (2007)
Publisher : BRIN Publishing

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A method for determining design characteristics of a wind turbine rotor has been developed. Given the desired power and operational wind speed, the approximate design diameter and rotor rpm can then be determined. The size of the rotor diameter is governed by the blade performance, in which is normally given as power coefficient Cp; designed rotor spedd can be known after calculating the tip spedd ratio. Using this method, the blade and rotor characteristics can be designed quickly as a preliminary design parameter. Keywords: Rancangan awal, Koefisien daya, Tip speed ratio.
SIMULASI PENGGUNAAN DIFFUSER PADA TURBIN ANGIN SUMBU HORISONTAL UNTUK KENAIKAN DAYA Atmadi, Sulistyo; Fitroh, Ahmad Jamaludin
Indonesian Journal of Aerospace Vol. 9 No. 1 Juni (2011): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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One technique to improve the power output of a wind turbine is by implementing a diffuser, which is called the diffuser augmented wind turbine (DAWT). The area ratio between the inlet and outlet of the diffuser increases the flow rate inside the diffuser which in effect produces higher output power. In this research, a 2 meters rotor diameter was used. Diffuser diameter ratio variation of 2, 3, 4, and 5 were chosen which provides inlet diameter of 4, 6, 8, and 10 meter respectively. Power rotor coefficient is assumed to be constant of 0.30. Air speed distribution inside the diffuser is calculated using CFD method. The inlet speed to the diffuser is varied to give 4 different speeds. The wind angle at the inlet is also varied at 0º, 30º and 60º. The simulation result showed that at 0 degree angle, diffuser diameter ratio variation of 2, 3, 4, and 5 will increase the power output about 58, 622, 3169, and 11519 times respectively. It also showed that the increase in the output power for diameter diffuser ratio of 2 at 0º and 60º angle is 58 and 4 times respectively.
ANALISIS LOSSES PIPA LURUS BERDIAMETER 40 cm PADA TEROWONGAN ANGIN LAPAN Fitroh, Ahmad Jamaludin
Indonesian Journal of Aerospace Vol. 9 No. 1 Juni (2011): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

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One of LAPAN’s programs is design and build the ramjet open tested wind tunnel. The lenght of pipe connecting between wind tunnel and storage tank was designed long enough so it was estimated there is big losses along the pipe. The object of this research is to calculation that losses, specially for the straight part only. The magnitude of the losses was gotten from simulation using software based on CFD theory. This research used two methods, i.e. based on pressure method and based on mass flow rate method. The simulation’s result using based on mass flow rate method gave the higher losses for the straight pipe so that result was chosen as the final result. That result was processed become the losses as a function of mass flow rate. The higher mass flow rate will produce the bigger losses. At mass flow rate of 60 kg/s, the losses is 0.135 %/m and at 100 kg/s the losses is 0.299 %/m. The relation between both parameter is close to linier curve.
Co-Authors Agus Ariwibowo, Agus Hartono, Firman Herdiana, Dana Saeri Sulistyo Atmadi