Karakteristik Aliran Dan Perpindahan Panas Simulasi Finned Tube 3 Dimensi High Pressure Evaporator HRSG Di PT. PJB Gresik

Ramadhi, Rizza (2014) Karakteristik Aliran Dan Perpindahan Panas Simulasi Finned Tube 3 Dimensi High Pressure Evaporator HRSG Di PT. PJB Gresik. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

HRSG merupakan pembangkit gabungan (siklus Brayton dan siklus Rankine) dimana gas buang atau exhaust gas yang masih panas dari siklus Brayton dimanfaatkan kembali oleh HRSG untuk memanasi fluida water sehingga nantinya uap panas digunakan untuk memutar turbin uap (siklus Rankine). Pada penelitian tugas akhir ini dilakukan simulasi numerik tiga dimensi pada circular finned tube. Variasi kecepatan fluida pada velocity inlet 4m/s, 9m/s, 24m/s, temperatur dinding steel yaitu 613K, temperatur flue gas (udara) 743K. Metode simulasi dari ketiga variasi tersebut menggunakan software computational fluid dynamic gambit 2.4.6 dan fluent 6.3.26. Hasil yang didapatkan dari penelitian ini adalah dengan kecepatan inlet 4m/s, 9m/s, 24m/s bahwa temperatur fin tertinggi terdapat pada fin row 2 yaitu untuk Re 2500 (kecepatan 4m/s), T = 680.058K; Re 5622 (kecepatan 9m/s), T = 694.631K; Re 15000 (kecepatan 24m/s), T = 712.837K. Nilai Nusselt Number maksimum terdapat pada tube row 2 yaitu untuk Re 2500 (kecepatan 4m/s), Nu = 54.149 pada sudut teta (θ) 64.28o; Re 5622 (kecepatan 9m/s), Nu = 74.2616 pada sudut teta (θ) 64.28o; Re 15000 (kecepatan 24m/s), Nu = 150.814 pada sudut teta (θ) 64.28o. Effectiveness fin maksimum terdapat pada Re 2500, untuk posisi C = 4.23, posisi B = 3.45, dan posisi A = 3.27. Effectiveness fin maksimum terdapat pada Re 2500, untuk posisi C = 4.14, posisi B = 3.38, dan posisi A = 3.09. Effectiveness fin maksimum terdapat pada Re 2500, untuk posisi C = 4.39, posisi B = 3.92, dan posisi A= 3.86. Bahwasannya Reynolds Number sangat berpengaruh terhadap karakteristik perpindahan panas. Nusselt Number akan meningkat seiring bertambahnya Reynolds Number. Effectiveness fin akan menurun seiring bertambahnya Reynolds Number, hal ini disebabkan Tf (temperatur rata-rata fin) akan meningkat seiring bertambahnya nilai Re maka ΔT akan menurun. Effectiveness fin atau fin performance pada setiap posisi (a, b, c) untuk masingmasing Reynolds Number sangat memenuhi karena nilai dari Ef ≥ 2 apabila Ef ≤ 2 maka desain fin tersebut kurang baik. ==================================================================================== HRSG is combined cycle powerplant (Brayton cycle and Rankine Cycle) in which the exhaust gases are still hot from the Brayton cycle is recovered by HRSG to warm the fluid water, so that the steam can be used to turn the steam turbine (Rankine cycle). In this thesis three-dimensional numerical simulations performed on circular finned tube. Variation of fluid velocity in the inlet velocity of 4m/s, 9m/s, 24m/s, steel wall temperature is 613K, the temperature of the flue gas (air) 743K. Simulation method of the three variations using software computational fluid dynamic gambit 2.4.6 and fluent 6.3.26. The results obtained from this study is the inlet velocity of 4m/s, 9m/s, 24m/s that the temperature is highest fin on fin row 2 ie for Re 2500 (speeds of 4m/s), T = 680.058K; Re 5622 (speed 9m/s), T = 694.631K; Re 15000 (speed of 24m/s), T = 712.837K. The maximum value of Nusselt Number contained in the tube row 2 ie for Re 2500 (speeds of 4m /s), Nu = 54.149 at an angle theta (θ) 64.28o; Re 5622 (speed 9m/s), Nu = 74.2616 at an angle theta (θ) 64.28o; Re 15000 (speed of 24m/s), Nu = 150.814 at an angle theta (θ) 64.28o. Maximum fin effectiveness are at Re 2500, for the position of C = 4.23, B = 3.45 position, and the position of A = 3.27. Maximum fin effectiveness are at Re 2500, for the position of C = 4.14, B = 3.38 position, and the position of A = 3.09. Maximum fin effectiveness are at Re 2500, to the position of the C = 4.39, position B = 3.92, and the position of A = 3.86. Reynolds Number greatly affect the heat transfer characteristics. Nusselt Number will increase with Reynolds Number. Fin effectiveness decreases with increasing Reynolds Number, this is due to Tf (average fin temperature) will increase with increasing Re, the ΔT value will decrease. Effectiveness fin or fin performance at each position (a, b, c) is suitable for each of the Reynolds Number because the value of Ef ≥ 2 if Ef ≤ 2 then the fin design is not good.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: HRSG; circular finned tube; metode numerik; perpindahan panas; numerical simuation method; heat transfer.
Subjects: T Technology > TJ Mechanical engineering and machinery
Divisions: Faculty of Industrial Technology > Mechanical Engineering > (S1) Undergraduate Theses
Depositing User: Mrs Anis Wulandari
Date Deposited: 24 May 2017 06:55
Last Modified: 24 May 2017 06:55
URI: http://repository.its.ac.id/id/eprint/41367

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