30 research outputs found
KAJIAN PENGEMBANGAN KAPAL WISATA BERBASIS ENERGI ALTERNATIF: KOMBINASI LAYAR DAN PANEL SURYA
Get PDFPotensi energi alternatif yaitu angin dan matahari dapat dimanfaatkan secara maksimal untuk membantu energi kapal wisata di Madura. Desain lambung yang digunakan adalah tipe monohull dan katamaran pada displasemen yang sama sebesar 6 ton, didapatkan besaran hambatan dengan menggunakan analisa numerik CFD yang diperlukan untuk menghitung kebutuhan daya terhadap kecepatan relatif kapal. Penyelidikan secara numerik dimulai dengan Pre-processing yang meliputi pembuatan geometri benda, dan meshing. tahap pemilihan solver yang meliputi pemilihan boundary-condition, pemilihan model laminar maupun turbulensi aliran, pemilihan jenis fluida dan struktur, dan pemilihan solving-equation bertujuan untuk mendapatkan data gaya-gaya hidrodinamika dan efeknya terhadap lambung kapal maupun layar pada saat menerima aliran fluida. Gaya yang dihasilkan oleh layar dengan bentuk segitiga dengan ukuran lebar sebesar 3 meter dan tinggi sebesar 4 meter, sebesar 0.812 kN. Luasan panel surya yang tersedia untuk kapal monohull sebesar 24m2 mampu memberikan konstribusi power sebesar 3.42 kW, sedangkan untuk tipe katamaran sebesar 54m2 mampu memberikan konstribusi power sebesar 7.7 kW. Kapal monohull dengan L = 12 m, B = 2.4 m, T = 1 m, menggunakan layar dan panel surya memberikan konstribusi kecepatan kapal sebesar 6 knot, sedangkan untuk kapal katamaran dengan ukuran utama L = 12 m , B = 6 m, T = 0.55 m, menggunakan layar dan panel surya memberikan konstribusi kecepatan kapal sebesar 8 knot.</p
Studi Aliran Sekunder Pada Kaskade Kompresor Linear Stagger Lemah dan Tanpa Tip Clearance Menggunakan Computational Fluid Dynamics
No full textIn an axial compressor, endwall region is a region with significant rise total losses. At this region, the complex phenomena of three dimensional flows (3D flow) happened which includes the interaction of blade boundary layer with casing-hub boundary layer. This interaction will cause secondary vortices that finally become secondary flow. The secondary flow formation will be followed by a blockage effect, a change in deflection angle and flow contraction to mid span. The worst effect of thesecondary flow is secondary losses. Based on that idea, this study is performed to examine structure three dimensional (3-D) field flows near endwall at linear compressor cascade without tip clearance. The experiment conducted numerically, Computational Fluid Dynamics with software FLUENT 6.0, model 3d, dp, segregate, RNG k-e turbulent. Cascade configuration using British airfoil 9C7/32,5C50 with stagger angle 300, and blade loading (a = 140, 180, 220). The research shows that with increasing blade loading on cascade causes saddle point movement to pressure side, intensity of cross passage flow and curl flow become stronger so blockage effect and energy losses occurring has a bigger value.
Abstract in Bahasa Indonesia :
Pada kompresor aksial, daerah endwall merupakan daerah dimana terjadi kenaikan total losses yang cukup besar. Pada daerah ini terjadi fenomena kompleks aliran tiga dimensi (3D) yang melibatkan interaksi antara lapisan batas sudu dengan lapisan batas hub atau casing. Interaksi ini akan mengakibatkan terjadinya vortisitas sekunder, yang akhirnya menjadi aliran sekunder. Terbentuknya aliran sekunder akan diikuti dengan penyumbatan aliran, perubahan sudut defleksi dan kontraksi aliran kearah midspan. Efek yang terbesar dari aliran sekunder ini adalah timbulnya kerugian sekunder. Berdasarkan pemikiran tersebut, dalam penelitian ini dilakukan kaji struktur medan aliran 3-D dekat dinding pada linear kaskade kompresor tanpa tip clearance. Penelitian dilakukan secara numerik, Computational Fluid Dynamics menggunakan paket program FLUENT 6.0, model 3d, dp, segregate, RNG k-e turbulent. Konfigurasi kaskade menggunakan airfoil British 9C7/32,5C50 dengan sudut stagger 300 dan pembebanan (a = 140, 180, 220). Hasil penelitian menunjukkan dengan meningkatnya sudut pembebanan pada kaskade menyebabkan saddle point bergerak ke arah pressure side, intensitas cross passage flow dan curl flow semakin kuat, sehingga penyumbatan aliran dan kerugian energi yang terjadi semakin besar.
Kata kunci: Kaskade kompresor, saddle point, cross passage flow, curl flow
Studi Aliran Sekunder Pada Kaskade Kompresor Linear Stagger Lemah dan Tanpa Tip Clearance Menggunakan Computational Fluid Dynamics
No full textIn an axial compressor, endwall region is a region with significant rise total losses. At this region, the complex phenomena of three dimensional flows (3D flow) happened which includes the interaction of blade boundary layer with casing-hub boundary layer. This interaction will cause secondary vortices that finally become secondary flow. The secondary flow formation will be followed by a blockage effect, a change in deflection angle and flow contraction to mid span. The worst effect of thesecondary flow is secondary losses. Based on that idea, this study is performed to examine structure three dimensional (3-D) field flows near endwall at linear compressor cascade without tip clearance. The experiment conducted numerically, Computational Fluid Dynamics with software FLUENT 6.0, model 3d, dp, segregate, RNG k-e turbulent. Cascade configuration using British airfoil 9C7/32,5C50 with stagger angle 300, and blade loading (a = 140, 180, 220). The research shows that with increasing blade loading on cascade causes saddle point movement to pressure side, intensity of cross passage flow and curl flow become stronger so blockage effect and energy losses occurring has a bigger value.
Abstract in Bahasa Indonesia :
Pada kompresor aksial, daerah endwall merupakan daerah dimana terjadi kenaikan total losses yang cukup besar. Pada daerah ini terjadi fenomena kompleks aliran tiga dimensi (3D) yang melibatkan interaksi antara lapisan batas sudu dengan lapisan batas hub atau casing. Interaksi ini akan mengakibatkan terjadinya vortisitas sekunder, yang akhirnya menjadi aliran sekunder. Terbentuknya aliran sekunder akan diikuti dengan penyumbatan aliran, perubahan sudut defleksi dan kontraksi aliran kearah midspan. Efek yang terbesar dari aliran sekunder ini adalah timbulnya kerugian sekunder. Berdasarkan pemikiran tersebut, dalam penelitian ini dilakukan kaji struktur medan aliran 3-D dekat dinding pada linear kaskade kompresor tanpa tip clearance. Penelitian dilakukan secara numerik, Computational Fluid Dynamics menggunakan paket program FLUENT 6.0, model 3d, dp, segregate, RNG k-e turbulent. Konfigurasi kaskade menggunakan airfoil British 9C7/32,5C50 dengan sudut stagger 300 dan pembebanan (a = 140, 180, 220). Hasil penelitian menunjukkan dengan meningkatnya sudut pembebanan pada kaskade menyebabkan saddle point bergerak ke arah pressure side, intensitas cross passage flow dan curl flow semakin kuat, sehingga penyumbatan aliran dan kerugian energi yang terjadi semakin besar.
Kata kunci: Kaskade kompresor, saddle point, cross passage flow, curl flow
The simulation of large-sized pathogen-laden respiratory droplet spread inside a passenger ferry
No full textThis paper presents computational fluid dynamics (CFD) of Reynolds-Averaged Navier Stokes (RANS) simulations to analyse the flow movement of pathogen-laden particles/droplets with relatively large diameter range of 50 − 150 μ m inside an air-conditioned ferry cabin. Three major cases are investigated, the first cases is when one infected passenger sits on a passenger chair that is located close to the edge of the cabin in the centre row; the second case is when the infected passenger is standing in the middle of the cabin; and the third case is for a passenger who sits on the opposite edge of the cabin, and located at the front row. For each of these three positions, three air conditioner velocities were investigated. The results indicate that as the air conditioner velocities velocity increases, the spread of the particles is also getting wider and they are elevated further from the floor. The simulation results also indicate that passenger location is also an important aspect in influencing the spread of the particles, particularly for those who are directly blown by the air conditioner’s airflow. Our results also show the effectiveness of 1.5-meter (minimum 1-meter) social distancing rule by the WHO (World Health Organisation) for particles with diameter range of 50 − 150 μ m, however there are certain cases in which this separation distance may be insufficient. Such as in which the infected patient is directly blown by the air conditioner or when the particle diameters are smaller than 50 μ m in which it could be suspended in the air longer. Finally, this report also discuss RANS validation technique with respect to experiment and the weakness of RANS in simulating the movement of particles inside a room. Hence the result of the simulation should be treated as an approximation only
New concept of solar-powered catamaran fishing vessel
Get PDFIt has been considered that the availability of fossil fuels is getting rare and hence becoming more\ud
expensive. Its exploration has moved from onshore to offshore together with advanced technology involved thus\ud
causing higher cost to the fuels to be ready to use. This fact has caused (in particulars) the fishermen cannot afford to\ud
buy the fuel so that they are vulnerable to live in poverty. Recent survey shows that more than 50% of fishing boats,\ud
owned by traditional and low economic income of Indonesian fishermen, has been grounded. In addition, the use of\ud
fossil fuels has caused the increase of green house gas (GHG) effects thus its continuous use is not environmentally\ud
friendly. The current paper describes the development of catamaran fishing vessel as a part of academic contribution to\ud
help the Indonesian fishermen. Earlier work proposed the design of catamaran fishing (cat-fish) vessel using the\ud
conventional diesel engine, whilst the new design introduces the use of combination of diesel engine together with the\ud
use of solar power. Discussion includes the explanation of lay out arrangement, ship stability and seakeeping\ud
characteristics, and energy index due to the use of two power system. The later item has now become a serious matter\ud
under IMO (International Maritime Organization) regulation in order to reduce GHG effect. Economic review of the\ud
possible development of the novel concept is also taken into consideration because the investment cost of the solar\ud
powered boat is predicted to be more expensive than the diesel powered vessel but its operational cost is cheaper hence\ud
it is promising in long-term use
Toward Improvement of Resistance Testing Reliability
Get PDFPeriodically conducting a benchmark test with estimated uncertainty is important to improve the quality of resistance predictions and understand the influence of instrumentation, testing procedures and analysis techniques. The LHI-007 Ro-Ro Ferry ship model, made available by the Maritime Research Institute Netherlands (MARIN), was used for benchmark testing from 2010 to 2018 at the Indonesian Hydrodynamic Laboratory. Comparisons were made between filtering the resistance data with a low-pass filter and with a Kalman filter. This work shows how benchmark tests can be used to track test performance over a longer period and proposes techniques to improve the uncertainty in the resistance results
An Investigation into the Operational Characteristics of High-Speed Crew Boat Based on Artificial Neural Network
Get PDFEstimating shaft power of a crew boat is very important to be analysed because it has high-speed operational characteristics along with limited routes. To understand the phenomena, 3 sister crew-boats with operational distance about 40-60 nautical miles every day are investigated. The daily operational time is 8 hours and the configurations are: 4.04% full speed, 13.63% economical speed, 1.81% slow speed, 7.65% snatching, 1.25% manoeuvring, 5.29% idle, and the remaining time is in standby condition. The crew boats are fitted with a monitoring system namely SHIMOS®, in which data is sent to a server in the centre office every 2 minutes. The data consists of time capture, boat position (latitude and longitude), speed, left and right RPM engine, left and right flow-meter data engine, and average of fuel consumption data in everyday operation. Three years of data has been collected for the vessel. The present study proposed characteristics of crew-boat shaft power, which affected by external factors using Artificial Neural Network (ANN) back propagation method and optimisation in 4 hidden layers and 40 neurons with relative error 6.2%. The results demonstrates good agreement with previous popular method that using statistical models
Computational Study on the Transmission of COVID-19 Virus Inside a Ship
Get PDFTo investigate the operational improvements of vessels under the impact of COVID-19, this work has developed a Computational Fluid Dynamics model combined with Lagrangian particles to study the airborne transmission of COVID-19 viruses inside a ship. Initially a generic model was established to enable validation against experimental results for the diffusion of flu virus in an idealised room. Following this, the room geometry was replaced by the superstructure of a full-scale crew boat. Considering the boat advancing in open water, simulations were conducted to study the particulate flow due to a person coughing and speaking, with the boat’s forward door open and closed. The results have shown that, when the forward door is open, a significant airflow can carry the viruses to make extensive contacts with the passengers. This led to the suggestion of keeping the door closed. However, when the forward door is shut, face-to-face speaking can generate viruses that can float in the air for a long time, and it was found that the viruses mainly stay within a half-meter distance in front of the speaking person, before sinking to attach to the deck. Thus, a social-distancing suggestion on seat arrangement has been highlighted to minimise the risk of contagion. Overall, this work is expected to inform guidelines on hygienic and reconfiguring means for operators to counter COVID-19 and potentially the spread of similar viruses in the future
Computational Fluid Dynamics Analysis Into the Improvement of Seakeeping Characteristics of a Fast Craft Using AXE-Bow
Get PDFIt is obviously understood that hull shape affects the movement characteristics and operability of a ship. There are several ways which can be conducted in order to improve the operability of a ship one of those is by improving ship bow. Recent development known as AXE-Bow was introduced by Delft University of Technology in collaboration with DAMEN Shipyard, in the Netherlands. It was reported that the AXE-Bow can improve the seakeeping characteristics of the vessel at higher speed (Froude number above 0.60), such as reduce vertical acceleration. The current work is carried out numerically using Computational Fluid Dynamics (CFD) approach together with the use of CFD code called Hydrostar provided by Bureau Veritas (BV). The overall results showed that there are good agreement between CFD method and the work by Delft University of University and DAMEN Shipyard. Comparative studies were also carried out with published data and demonstrated similar finding
Studi Aliran Sekunder Pada Kaskade Kompresor Linear Stagger Lemah Dan Tanpa Tip Clearance Menggunakan Computational Fluid Dynamics
Get PDFIn an axial compressor, endwall region is a region with significant rise total losses. At this region, the complex phenomena of three dimensional flows (3D flow) happened which includes the interaction of blade boundary layer with casing-hub boundary layer. This interaction will cause secondary vortices that finally become secondary flow. The secondary flow formation will be followed by a blockage effect, a change in deflection angle and flow contraction to mid span. The worst effect of thesecondary flow is secondary losses. Based on that idea, this study is performed to examine structure three dimensional (3-D) field flows near endwall at linear compressor cascade without tip clearance. The experiment conducted numerically, Computational Fluid Dynamics with software FLUENT 6.0, model 3d, dp, segregate, RNG k-e turbulent. Cascade configuration using British airfoil 9C7/32,5C50 with stagger angle 300, and blade loading (a = 140, 180, 220). The research shows that with increasing blade loading on cascade causes saddle point movement to pressure side, intensity of cross passage flow and curl flow become stronger so blockage effect and energy losses occurring has a bigger value
