Simulasi Numerik Pengaruh Variasi Luas Penampang Inlet, Saluran Utama, dan Tipe Elbow Return Duct Terhadap Kenyamanan Termal di dalam Kabin Kereta Cepat Merah Putih (KCMP)

Muhammad Falih Addaffa, Ir. Fauzun, S.T., M.T., Ph.D., IPM., ASEAN Eng.

2026 | Skripsi | TEKNIK MESIN

Kereta Cepat Merah Putih (KCMP) yang dikembangkan PT INKA bersama sembilan perguruan tinggi negeri membutuhkan sistem pengondisian udara kabin yang memenuhi standar kenyamanan termal Peraturan Menteri Perhubungan Nomor 7 Tahun 2022. Penelitian HVAC KCMP sebelumnya berfokus pada sisi suplai, sedangkan pengaruh geometri return duct terhadap distribusi temperatur dan kelembapan di zona hunian belum diuji. Penelitian ini menganalisis pengaruh luas penampang inlet return duct, geometri elbow transisi, serta luas dan bentuk penampang main return duct terhadap pola aliran dan kenyamanan termal kabin KCMP.

Simulasi computational fluid dynamics (CFD) steady-state dilakukan menggunakan ANSYS Fluent 2024 R1 pada domain kabin MC-1 KCMP. Sembilan konfigurasi disusun dalam tiga tahap bertingkat, dengan konfigurasi terbaik tiap tahap menjadi dasar tahap berikutnya. Kenyamanan termal dievaluasi menggunakan indeks performa pada 40 titik peninjauan.

Luas penampang inlet 125% luas existing menjadi konfigurasi terbaik tahap pertama. Variasi 5, yaitu mitered elbow 135 derajat dengan fillet radius 50 mm, mencatat indeks performa gabungan tertinggi (60%) sehingga menjadi konfigurasi terbaik, dengan ketiga kriteria kenyamanan termal terpenuhi pada 24 dari 40 titik peninjauan dibandingkan 15 titik pada desain existing

The Red and White High-Speed Train (KCMP), developed by PT INKA together with nine state universities, requires a cabin air conditioning system that meets the thermal comfort standard of Ministry of Transportation Regulation No. 7 of 2022. Previous KCMP HVAC research focused on the supply side, whereas the effect of return duct geometry on temperature and humidity distribution in the occupied zone has not yet been examined. This research analyzes the effects of the return duct inlet cross-sectional area, transition elbow geometry, and main return duct cross-sectional area and shape on airflow patterns and thermal comfort in the KCMP cabin.

Steady-state computational fluid dynamics (CFD) simulations were performed using ANSYS Fluent 2024 R1 on the KCMP MC-1 cabin domain. Nine configurations were arranged into three sequential stages, with the best configuration of each stage serving as the basis for the next. Thermal comfort was evaluated using a performance index at 40 review points.

An inlet cross-sectional area of 125% of the existing area was the best configuration in the first stage. Variation 5, 135 degree mitered elbow with 50 mm fillet radius, recorded the highest combined performance index (60%) and was therefore the best configuration, meeting all three thermal comfort criteria at 24 of 40 review points compared with 15 points in the existing design

Kata Kunci : Simulasi CFD, KCMP, Return Duct, Kenyamanan Termal, Distribusi Aliran Udara