Rizal, Karisma (2015) Studi numerik pengaruh jarak transisi 2D, 3D, 4D, 5D, 7D, existing, dan 10D, antara secondary superheater dan boilerbank tube serta pengaruh susunan tube aligned dan staggered terhadap karakteristik aliran dan perpindahan panas konveksi. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Rendahnya efisiensi pembangkit pada unit 1 dan 2 PLTU
PT.Indonesia Power Perak menyababkan 2 unit tersebut dimatikan
secara permanen sejak 1995. Pada 2012 unit 3 dan 4 dimatikan
sementara hingga efisiensi pembangkit ini dapat ditingkatkan.
Penggantian bahan bakar dari MFO menjadi gas menjadi salah
satu solusi yang diberikan. Solusi lain yang ditawarkan adalah
dengan meningkatkan perpindahan panas tube-tube boiler
khusunya pada secondary superheater dan boilerbank tube.
Penelitian dilakukan dengan memvariasikan jarak
transisi antara secondary superheater dan boilerbank tube sebesar
2D, 3D, 4D, 5D, 7D, existing, dan 10D. Fluida kerja berupa gas
sisa hasil pembakaran yang diasumsikan sebagai gas ideal dengan
kecepatan sebesar 5.46 m/s pada pembebanan 100% yang
mengalir pada sisi eksternal tube dengan temperatur 1000 K.
Boundary condition yang diambil adalah 3 baris tube pada
secondary superheater, 2 baris tube pada boilerbank tube
staggered, dan 2 baris tube pada aligned boilerbank tube. Studi
numerik dilakukan secara 2 dimensi dengan aliran steady dengan
prinsip Computational Fluid Dynamic (CFD) dangan menggunakan software GAMBIT 2.4.6 untuk membuat geometri
dari domain dan software FLUENT 6.3.26 untuk mensimulasikan.
Dari penelitian yang telah dilakukan, didapatkan grafik
Nusselt lokal pada susunan tube aligned dan susunan tube
staggered, grafik Nusselt rata-rata secondary superheater dan
boilerbank tube pada seluruh variasi, serta grafik perbandingan
Nusselt lokal pada seluruh variasi. Susunan tube bank Staggered
memiliki nilai Nusselt Number lokal dan rata-rata yang lebih
tinggi dibandingkan susunan tube bank Aligned. Serta didapatkan
kesimpulan bahwa variasi jarak transisi tidak memiliki efek yang
signifikan terhadap perpindahan panas pada secondary
superheater dan boilerbank tube tipe aligned, namun memiliki
pengaruh yang signifikan terhadap boilerbank tube tipe staggered.
Kecepatan inlet boilerbank tube tipe staggered berturut-turut pada
variasi jarak transisi 2D, 3D, 4D, 5D, 7D adalah 8.94 m/s, 7.31
m/s, 6.3 m/s, 5.64 m/s, 4.72 m/s, dan jarak transisi existing dan
10D dengan kecepatan sama sebesar 4.5 m/s. Peningkatan Nusselt
Number tertinggi terjadi pada variasi jarak transisi 2D dengan
peningkatan Nusselt pada tube pertama sebesar 18.98% dan pada
tube kedua sebesar 6.97% dibandingkan dengan kondisi existing.
Pressure Drop yang terjadi pada seluruh variasi menunjukkan
nilai yang relatif sama.
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Because of The low efficiency of the power plant units 1
and 2 PT.Indonesia Power Perak Surabaya is permanently
disabled since 1995. In 2012, units 3 and 4 is temporary disabled
until this power plant efficiency can be improved. Replacement of
MFO fuel into gas fuel is one of the solutions provided. Another
solution offered is to increase the heat transfer in boiler tubes
especially at the secondary boiler superheater and boilerbank
tube.
The study is concerning of varying the transition distance
between the secondary superheater and boilerbank tube for 2D,
3D, 4D, 5D, 7D, existing, and 10D. The working fluid is fluel gas
that assumed as an ideal gas at a rate of 5,46 m/s flowing on the
external side of the tube with a temperature of 1000 K. The
boundary condition is 3 rows of tubes in the secondary superheater
, 2 rows of tubes in boilerbank staggered, and 2 rows of tube in
tube boilerbank aligned. Numerical study conducted twodimensional
steady flow with the principle of Computational Fluid
Dynamic (CFD) using GAMBIT 2.4.6 software to create the
geometry of the domain and FLUENT 6.3.26 software to simulate. The results of this study showed local Nusselt chart of
aligned tube arrangement and staggered tube arrangement,
average Nusselt charts of secondary superheater and boilerbank
tubes in all variations, and local Nusselt charts compared on all
variations. Staggered arrangement tube bank has the higher local
and average value of Nusselt Number than Aligned arrangement
tube bank. the result showed that the variations within the
transition distance does not have a significant effect on heat
transfer at the secondary superheater and aligned boilerbank tube,
but has a significant effects on heat transfer at staggered
boilerbank tube. the inlet velocity at staggered boilerbank tube on
the transition distance variation 2D, 3D, 4D, 5D, 7D, existing, and
10D is 8.94 m/s, 7.31 m/s, 6.3 m/s, 5.64 m/s, 4.72 m/s, existing and
10D has the same speed 4.5 m/s. the highest increased of nusselt
number at 2D transition distance, the nusselt number of first tube
increased by 18,8% and the second tube increased by 6,6%
compared to the existing conditions. Pressure Drop which occurs
in all variations showed the same relative value.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSM 621.402 2 Riz s |
| Uncontrolled Keywords: | external flow, superheater, powerplant, variasi jarak transisi, heat transfer |
| Subjects: | Q Science > QC Physics > QC320 Heat transfer |
| Divisions: | Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | - Taufiq Rahmanu |
| Date Deposited: | 22 Nov 2019 06:53 |
| Last Modified: | 22 Nov 2019 06:53 |
| URI: | http://repository.its.ac.id/id/eprint/71979 |
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