Analisis Numerik Perbandingan Sudut Helix Rotor Screw Compressor Pada OSc 45 U

Pratama, Dzakiy Rizqi (2026) Analisis Numerik Perbandingan Sudut Helix Rotor Screw Compressor Pada OSc 45 U. Diploma thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Efisiensi energi merupakan faktor kritis dalam pengembangan kompresor sekrup ganda (twin-screw compressor) yang banyak digunakan pada sektor industri. Penelitian ini bertujuan untuk menginvestigasi dampak variasi sudut helix rotor secara sistematis terhadap kinerja aerotermodinamika internal dan karakteristik aliran fluida udara pada kompresor Özen Kompresör OSC 45 U. Analisis numerik dilakukan menggunakan metode Computational Fluid Dynamics (CFD) berbasis moving wall pada kondisi operasional 1900" RPM" dengan membandingkan desain eksisting sudut helix 46,73^∘ dan modifikasi sudut helix 48,00^∘. Hasil validasi pemodelan numerik pada kondisi baseline (46,73^∘) menunjukkan tingkat kesesuaian yang sangat tinggi terhadap referensi literatur dengan deviasi efisiensi volumetrik sebesar 0,25% (η_v=80,50%) dan efisiensi adiabatik netto sebesar 2,59% (η_a=68,23%). Peningkatan sudut helix dari 46,73^∘ menjadi 48,00^∘ terbukti secara signifikan meningkatkan efisiensi volumetrik kompresor sebesar +6,28% (dari 80,50% menjadi 86,78%). Hal ini disebabkan oleh lintasan garis penyegelan (sealing line) yang lebih panjang pada sudut 48,00^∘, yang secara efektif meningkatkan hambatan aliran balik dan menekan laju kebocoran internal (internal back-leakage). Selain itu, efisiensi adiabatik netto fluida gas juga mengalami peningkatan sebesar +0,41% (dari 68,23% menjadi 68,64%). Distribusi kontur kecepatan memperlihatkan bahwa sudut 48,00^∘ mampu meredam kecepatan puncak pada discharge port dari 48,2" m/s" menjadi 41,4" m/s" serta menghilangkan fenomena jet flow core, sehingga menekan rugi penyempitan (throttling losses) dan turbulensi lokal. Secara keseluruhan, penelitian ini menyimpulkan bahwa modifikasi sudut helix ke 48,00^∘ menghasilkan performa aerotermodinamika yang lebih optimal dan efisien energi.
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Energy efficiency is a critical factor in the development of twin-screw compressors, which are widely used in industrial applications. This study aims to systematically investigate the effect of rotor helix angle variation on the internal aerothermodynamic performance and airflow characteristics of the Özen Kompresör OSC 45 U screw compressor. Numerical analysis was conducted using the Computational Fluid Dynamics (CFD) method with a moving wall approach under an operating speed of 1900 rpm, comparing the baseline rotor design with a 46.73° helix angle and a modified design with a 48.00° helix angle. Validation of the numerical model under the baseline condition (46.73°) demonstrated excellent agreement with published reference data, yielding deviations of only 0.25% for volumetric efficiency ( 80.50%) and 2.59% for net adiabatic efficiency 68.23%). Increasing the rotor helix angle from 46.73° to 48.00° significantly improved the compressor's volumetric efficiency by 6.28%, increasing from 80.50% to 86.78%. This improvement is attributed to the longer sealing line associated with the 48.00° helix angle, which effectively increases resistance to reverse flow and suppresses internal back-leakage. Furthermore, the net adiabatic efficiency of the compressed gas increased by 0.41%, from 68.23% to 68.64%. Velocity contour analysis revealed that the 48.00° helix angle reduced the peak discharge-port velocity from 48.2 m/s to 41.4 m/s and eliminated the jet flow core phenomenon, thereby reducing throttling losses and local turbulence. Overall, the results demonstrate that modifying the rotor helix angle to 48.00° provides superior aerothermodynamic performance and improves the energy efficiency of the OSC 45 U twin-screw compressor.

Item Type:	Thesis (Diploma)
Uncontrolled Keywords:	CFD, SCREW COMPRESSOR,SUDUT HELIKS,HELIX ANGLE
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ1058 Rotors T Technology > TJ Mechanical engineering and machinery > TJ265.E23 Thermodynamics. T Technology > TJ Mechanical engineering and machinery > TJ990 Compressors
Divisions:	Faculty of Vocational > Mechanical Industrial Engineering (D4)
Depositing User:	Dzakiy Rizqi Pratama
Date Deposited:	01 Aug 2026 04:46
Last Modified:	01 Aug 2026 04:46
URI:	http://repository.its.ac.id/id/eprint/141236

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