Simulasi Pengaruh Modifikasi Lubang Pendingin Dengan Variasi Coolant Mass Flow Rate Terhadap Pendinginan Pada NASA C3X Turbine Vane

Clarence, Even (2021) Simulasi Pengaruh Modifikasi Lubang Pendingin Dengan Variasi Coolant Mass Flow Rate Terhadap Pendinginan Pada NASA C3X Turbine Vane. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Salah satu cara meningkatkan efisiensi termal turbin gas adalah dengan meningkatkan inlet temperature turbin. Temperatur kerja turbin yang sangat tinggi membuat panas yang ditransfer ke sudu turbin juga meningkat. Temperatur yang terlalu tinggi dapat memberi efek negatif pada umur dan mechanical properties sudu turbin. Oleh karena itu diperlukan suatu terobosan baru yang mampu mendinginkan sudu turbin sehingga kerja dari mesin turbin gas menjadi maksimal. Dari sekian banyak teknologi pendinginan yang ada saat ini, salah satu teknologi yang paling sering dipakai adalah teknologi pendinginan dari dalam yang mampu menjaga temperatur sudu turbin yang diinginkan selama pengoperasian mesin turbin gas.
Penelitian ini dilakukan menggunakan software ANSYS Workbench 19.2. Simulasi tiga dimensi dilakukan dengan menggunakan geometri NASA C3X Turbine Vane dengan sepuluh lubang pendingin yang diperoleh dari eksperimen oleh Hylton et al. (1983). Kondisi pengoperasian simulasi menggunakan data eksperimen Hylton et al. dengan kode 5421. Simulasi dilakukan dengan variasi normal (non-modifikasi), modifikasi dan modifikasi dengan variasi coolant mass flow rate sebesar ṁ -10%, ṁ +10%, dan ṁ +20%. Sudu turbin normal dan modifikasi memiliki perbedaan yang terletak pada jumlah, koordinat dan diameter lubang pendingin. Dari simulasi yang dilakukan akan didapatkan data kualitatif dan kuantitatif. Data kualitatif berupa kontur distribusi tekanan, temperatur dan kecepatan. Sedangkan data kuantitatif berupa nilai tekanan, temperatur, koefisien perpindahan panas dan laju perpindahan panas total beserta grafik dan tabel perbandingannya.
Hasil simulasi dan perhitungan menunjukkan jika modifikasi lubang pendingin memiliki performansi pendinginan yang lebih buruk daripada non-modifikasi. Secara keseluruhan, modifikasi lubang pendingin meningkatkan temperatur permukaan vane sebesar 3,29% yang setara dengan 20,85 K, menurunkan koefisien perpindahan panas permukaan vane sebesar 16,43% yang setara dengan 72,85 W/m2K dan menurunkan laju perpindahan panas total sebesar 13,51% yang setara dengan 648,14 W. Sedangkan pada variasi coolant mass flow rate menunjukkan jika semakin meningkatnya coolant mass flow rate maka akan meningkatkan performansi pendinginan. Secara keseluruhan, jika dibandingkan terhadap variasi ṁ normal, variasi dengan peningkatan coolant mass flow rate terbesar yaitu ṁ +20% menurunkan temperatur permukaan vane sebesar 2,21% yang setara dengan 14,48 K, meningkatkan koefisien perpindahan panas permukaan vane sebesar 23,55% yang setara dengan 87,22 W/m2K dan meningkatkan laju perpindahan panas total sebesar 8,13% yang setara dengan 337,3 W.
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One way to increase the thermal efficiency of gas turbine is increasing the turbine inlet temperature. The very high operating temperature of the turbine makes the heat transferred to the turbine vane also increase. Temperature that is too high can have a negative effect on the life and mechanical properties of turbine vane. Therefore we need a new breakthrough that can cool the turbine vane so that the work of the gas turbine engine can be maximized. Of the many cooling technologies currently available, one of the most frequently used technologies is internal cooling technology which is able to maintain the desired temperature of the turbine vane during the operation of a gas turbine engine.
This research was conducted using ANSYS Workbench 19.2 software. Three-dimensional simulations were carried out using the NASA C3X Turbine Vane geometry with ten cooling holes obtained from experiments by Hylton et al. (1983). Simulation operating conditions using experimental data Hylton et al. with code 5421. Simulations were carried out with normal variations (non-modification), modification and modification with variations of coolant mass flow rate of ṁ -10%, ṁ +10%, and ṁ +20%. The normal and modified turbine vane differ in the number, coordinates and diameter of the cooling holes. From the simulation, qualitative and quantitative data will be obtained. Qualitative data in the form of pressure, temperature and velocity distribution. While quantitative data in the form of pressure, temperature, heat transfer coefficient and total heat transfer rate along with graphs and comparison tables.
The simulation results and calculations show that the modified cooling hole has a worse cooling performance than the non-modified. Overall, the cooling hole modification increases the vane surface temperature by 3.29% which is equivalent to 20.85 K, reduces the vane surface heat transfer coefficient by 16.43% which is equivalent to 72.85 W/m2K and reduces the total heat transfer rate by 13.51% which is equivalent to 648.14 W. The variation of the cooling mass flow rate shows that increasing the cooling mass flow rate will increase the cooling performance. Overall, when compared to the normal variation, the variation with the largest increase in coolant mass flow rate is which is ṁ +20% reduces the vane surface temperature by 2.21% which is equivalent to 14.48 K, increases the vane surface heat transfer coefficient by 23.55 % which is equivalent to 87.22 W/m2K and increases the total heat transfer rate by 8.13% which is equivalent to 337.3 W.

Item Type:	Thesis (Undergraduate)
Uncontrolled Keywords:	Turbin gas, internal cooling, NASA C3X Turbine Vane, modifikasi, mass flow rate, temperatur, koefisien perpindahan panas, laju perpindahan panas Gas turbine, internal cooling, NASA C3X Turbine Vane, modification, mass flow rate, temperature, heat transfer coefficient, heat transfer rate
Subjects:	T Technology > TJ Mechanical engineering and machinery
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User:	Even Clarence
Date Deposited:	09 Aug 2021 01:03
Last Modified:	09 Aug 2021 01:03
URI:	http://repository.its.ac.id/id/eprint/85141

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