Studi Numerik Peningkatan Cooling Performance Pada Lube Oil Cooler Gas Turbine Yang Disusun Secara seri Dan Paralel Dengan Variasi Kapasitas Aliran Lube Oil (Studi Kasus PT. EMP Unit Bisnis Malacca Straits)

Wibowo, Annis Khoiri (2014) Studi Numerik Peningkatan Cooling Performance Pada Lube Oil Cooler Gas Turbine Yang Disusun Secara seri Dan Paralel Dengan Variasi Kapasitas Aliran Lube Oil (Studi Kasus PT. EMP Unit Bisnis Malacca Straits). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Salah satu komponen pada gas turbine adalah lube oil cooler yang berfungsi sebagai heat exchanger untuk mendinginkan temperatur lube oil. Masih tingginya temperatur lube oil sebelum masuk gas turbine merupakan kegagalan lube oil cooler dalam menurunkan temperatur lube oil sehingga diperlukan improvement untuk meningkatkan efektifitas pendinginan lube oil cooler. Oleh karena itu dilakukan simulasi untuk melihat pengaruh pemasangan susunan tiga lube oil cooler secara seri dan paralel dengan variasi kapasitas lube oil terhadap performance lube oil cooler. Pada penelitian ini dilakukan simulasi menggunakan studi Computational Fluid Dynamic (CFD) untuk mengetahui performance lube oil cooler. Simulasi dilakukan secara 3 dimensi dengan model turbulensi berupa k-ε RNG dengan solver pressure based solution. Tahap awal dilakukan pengambilan data dilapangan berupa data desain dan geometri lube oil cooler sebagai dasar pembuatan domain, serta data operasional sebagai acuan kondisi batas dalam proses simulasi. Dari data yang didapat kemudian dilakukan simulasi secara eksternal flow untuk memperoleh nilai koefisien heat transfer pada masing-masing tube dan variasi kapasitas lube oil. Nilai koefisien heat transfer tersebut nantinya dijadikan nilai input pada tube untuk simulasi internal flow pada pemasangan susunan lube oil cooler secara seri dan paralel dengan variasi flow rate lube oil 30 gpm, 50 gpm, 74 gpm. Dari hasil simulasi, flow ratio lube oil untuk masing�masing tube pada susunan lube oil cooler dipasang seri lebih seragam dari pada susunan lube oil cooler dipasang paralel, ditunjukkan dengan standard deviasi dari flow ratio masing�masing tube, pada kapasitas 50 gpm untuk susunan seri (0,46) lebih rendah daripada susunan paralel (0,75). Pada kapasitas 30 gpm, 50 gpm dan 74 gpm untuk susunan cooler seri secara berurutan memiliki standard deviasi flow ratio sebesar 0,33, 0,46 dan 0,55. Sehingga semakin kecil kapasitas lube oil, maka flow ratio lube oil masing-masing tube semakin seragam yang menyebabkan efektifitas pendinginan akan semakin baik. Susunan cooler dipasang seri menghasilkan efektifitas pendinginan yang lebih baik dibandingkan susunan paralel, ditunjukkan dengan rendahnya temperatur lube oil keluar cooler pada kapasitas 50 gpm sebesar 68,753°C untuk susunan cooler seri dan 72,575°C untuk susunan paralel, namun susunan cooler seri menghasilkan pressure drop yang lebih besar daripada susunan paralel. Pengoperasian kapasitas lube oil 30 gpm pada susunan cooler seri menghasilkan temperatur keluar cooler 62,8°C dan paralel sebesar 66,5°C. Kondisi tersebut telah memenuhi syarat temperatur lube oil sebelum masuk gas turbine dengan ketentuan temperatur inlet cooler dijaga konstan. Sehingga penurunan temperatur outlet dibandingkan dengan kondisi existing sebesar 5,5°C untuk susunan cooler seri dan 1,8°C untuk susunan cooler paralel.
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One of the components of gas turbine is lube oil cooler that serves as a heat exchanger to cool the temperature of the lube oil. Still the high temperature of lube oil before entering the gas turbine is the failure of the lube oil cooler in lowering the temperature of the lube oil. So that needed improvement to increase the cooling effectiveness of lube oil cooler. Therefore simulations is conducted to see the influence of the installation of three lube oil cooler in series and parallel arrangement with the variation of capacity of lube oil to see lube oil cooler performanceThe research was conducted simulation study of (CFD)Computational Fluid Dynamic to know the performance of lubeoil cooler. The simulation is done in 3 dimensions with turbulence model k-ε RNG with a pressure-based solver solutions. The first step is taking of field data. There are consists of data design and lube oil cooler geometry as the basis for the creating of the domain, as well as operational data as a reference boundary condition in the process simulation. From the data obtained is then performed a simulation of externally flow to obtain the value of the coefficient of heat transfer on each tube and lube oil capacity variation. The heat transfer coefficient value was later made into the input value on the tube for internal flow simulation on the installation of lube oil cooler in series and parallel arrangement with the variation of the flow rate of lube oil 30 gpm, 50 gpm, 74 gpm. The results of this research that flow ratio of lube oil for each tube in the instalation of the lube oil cooler are mounted series more uniform than parallel, this is indicated by the standard deviation of flow ratio in each tube, at a capacity of 50 gpm for a series arrangement (0.46) is lower than the parallel arrangement (0.75). The capacity of lube oil at 30 gpm, 50 gpm and 74 gpm for series arrangements sequentially has a standard deviation of flow ratio of 0.33, 0.46 and 0.55. So that the three coolers are installed in series arrangements produce cooling effectiveness better than the parallel arrangements, shown by the low temperature of lube oil cooler outlet at a capacity 50 gpm get temperatur outlet about 68.753 °C in series arrangements and 72.575 °C in parallel arrangements, but the series arrangement produces pressure drop greater than the parallel arrangement. The greater lube oil capacity in series or parallel arrangement, it will produce lube oil outlet temperature and pressure drop increases. The operation at 30 gpm lube oil capacity on the series arrangements produces temperature outlet about 62.8 °C and 66.5 °C in parallel arrangements. These conditions are qualified lube oil temperature before entering the gas turbine with the provisions of the same at inlet temperature cooler. So that the outlet temperature decrease if that is compared to the existing conditions at 5.5 °C for the series cooler arrangements and 1.8 °C for parallel cooler arrangements.

Item Type: Thesis (Other)
Additional Information: RSM 621.165 Wib s
Uncontrolled Keywords: Studi Numerik; Lube Oil Cooler; Series and Parallel Arrangements; Uniformity; Fluent
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ778 Gas turbines
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Mr. Marsudiyana -
Date Deposited: 08 Jun 2023 08:40
Last Modified: 08 Jun 2023 08:40
URI: http://repository.its.ac.id/id/eprint/98066

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