Investigation on the Performance of a Ducted Propeller in Oblique Flow

Abstract

In this study, the ducted propeller has been numerically investigated under oblique flow, which is crucial and challenging for the design and safe operation of thruster driven vessel and dynamic positioning (DP) system. A Reynolds-Averaged Navier-Stokes (RANS) model has been first evaluated in the quasi-steady investigation on a single ducted propeller operating in open water condition, and then a hybrid RANS/LES model is adapted for the transient sliding mesh computations. A representative test geometry considered here is a marine model thruster which is discretized with structured hexahedral cells, and the gap between the blade tip and nozzle is carefully meshed to capture the flow dynamics. The computational results are assessed by a systematic grid convergence study and compared with the available experimental data. As a part of novel contribution, multiple incidence angles from 15 • to 60 • have been analyzed with varying advance coefficients. The main emphasis has been placed on the hydrodynamic loads that act on the propeller blades and nozzle as well as their variation with different configurations. The results reveal that while the nozzle absorbs much effort from the oblique flow, the imbalance between blades at different positions is still noticeable. Such unbalance flow dynamics on the blades and the nozzle has a direct implication on the variation of thrust and torque of a marine thruster.

Investigasi Aliran Pada Thruster Rov (Remotely Operated Vehicle) Menggunakan Metode CFD

“…Melalui pemodelan tersebut, maka dapat dipilih konfigurasi thruster yang memiliki thrust paling optimum. Adapun metode pendekatan CFD yang digunakan adalah Moving Reference Frame (MRF) dengan model boundary condition sesuai Gambar 2, yang mana pengaturan didasarkan pada diameter terluar objek analisis (Bahatmaka et al, 2016(Bahatmaka et al, , 2017Joung et al, 2014;Majdfar et al, 2017;Voerman, 2012;Zhang et al, 2020).…”

“…Boundary condition of open water propeller (Bahatmaka et al, 2016(Bahatmaka et al, , 2017 Metode MRF yang diterapkan menggunakan konsep frozen rotor pada frame change/mixing pemodelan CFD. Lebih lanjut, terdapat dua domain utama dalam MRF ini, yaitu stationary domain yang meliputi fluida di sekitar propeller dan rotating domain yang meliputi propeller dengan ukuran mesh yang lebih kecil dibandingkan stationary domain (Joung et al, 2014;Majdfar et al, 2017;Voerman, 2012;Zhang et al, 2020). Perbedaan ukuran mesh dimaksudkan untuk mendapatkan komputasi yang lebih teliti meskipun membutuhkan waktu yang lebih lama (Darmawan & Tanujaya, 2019).…”

“…Di sisi lain, aplikasi kort nozzle sebagai thruster ROV dapat menurunkan torsi yang dibutuhkan untuk memutar propeller sebesar 6,633%. Fenomena ini sesuai dengan penelitian yang dilakukan untuk mengetahui pengaruh operating condition berdasarkan variabel J terhadap thrust dan torsi propeller yang telah dilakukan oleh (Zhang et al, 2020). Mengacu pada penelitian yang telah dilakukan, maka konfigurasi model thruster yang terdiri dari propeller 3-blade dengan kort nozzle dipilih sebagai rekomendasi untuk thruster ROV 2021.…”

Effects of a nozzle on the propeller wake in an oblique flow using modal analysis

“…For instance, when a ship changes its direction, the lateral flow can strongly modify the propeller propulsive loads, thus affecting the ship dynamic response and inducing the thruster–hull interaction (Viviani et al. 2007; Dubbioso, Muscari & Di Mascio 2013, 2014; Di Mascio, Muscari & Dubbioso 2014; Zhang, Ma & Liu 2018; Qiu et al. 2020).…”

“…propellers, wind and tidal turbines) that are initially designed to operate under uniform and axisymmetric flow are sometimes required to work in off-design conditions for manoeuvring (Felli & Falchi 2018;Huang, Qin & Pan 2022) or optimal energy extraction (Li & Yang 2021;Borg et al 2022). For instance, when a ship changes its direction, the lateral flow can strongly modify the propeller propulsive loads, thus affecting the ship dynamic response and inducing the thruster-hull interaction (Viviani et al 2007;Dubbioso, Muscari & Di Mascio 2013Zhang, Ma & Liu 2018;Qiu et al 2020). Analogously, in a large wind farm, to avoid the unfavourable wake interaction between two wind turbines, an active yaw control strategy has been adopted to deflect the upstream turbine wakes away from the downwind turbines and to increase the total power production of the wind turbine array (Bastankhah & Porté-Agel 2016;Zong & Porté-Agel 2020;Bossuyt et al 2021;Li & Yang 2021).…”