Exhaust Gas Treatment in Marine Compression Ignition Engines: Design and Efficiency Assessment of a Wet Scrubber System Manh D. Vu, Duoc V. Phung, Kien T. Nguyen, Phuong X. Pham Journal of Energy Resources Technology Part A Sustainable and Renewable Energy, 2026 Under the Convention for the Prevention of Pollution from Ships, particulate matter (PM) and nitrogen oxides (NOx) emissions from marine engines are controlled, whereas hydrocarbon (HC) emission is not explicitly regulated. PM is mainly managed indirectly through limits on fuel sulfur content, known as the "global sulfur cap". In addition, regional frameworks such as the European Union impose further limits on marine engines, while NOx is addressed through Tier I–III standards. In response to increasingly stringent emission requirements, this study evaluates the feasibility and design optimization of a wet scrubber for diesel engine exhaust treatment. High-speed shadowgraph imaging was used to study multiphase interactions in the scrubber. A Photron Fastcam (up to 200,000 fps), high-frequency LED, and a ground-glass diffuser provided uniform backlighting. Micro lenses achieved 3.8 µm/pixel resolution, enabling detailed analysis of spray cone angle, droplet size distribution, and liquid-sheet breakup length. The optimized design minimized unfavorable spray–spray and spray–wall interactions, improving gas–liquid contact efficiency. Three scrubbing media—water, sodium chlorite (NaClO2), and hydrogen peroxide (H2O2)—were investigated. Experimental results achieved soot removal efficiencies of up to 70%, primarily through impaction and coagulation mechanisms. Optimal performance occurred at 75% engine load with a liquid-to-gas ratio of 5 l/Nm3. However, gaseous pollutant removal remained limited, with maximum reductions of 15% for NOx using NaClO2 and 4% for HC. These findings support effective soot reduction but indicate that hybrid or catalytic solutions are needed for comprehensive emission compliance.
Influences of High-Pressure Pump and Injector Nozzle Geometry on Hydraulics Characteristics of a Mechanical Diesel Direct-Injection System Quan Q. Nguyen, Manh D. Vu, Duoc V. Phung, Kien T. Nguyen, Tuan N. Vu*, et al. SAE Technical Papers, 2024 <div class="section abstract"><div class="htmlview paragraph">The geometry of high-pressure pump and injector nozzles crucially influences hydraulic behaviors (e.g., the start of injection, the pressure profiles developed in the high-pressure line, needle lift, and injection rates) in diesel engines. These factors, in turn, significantly impact fuel atomization, fuel–air mixing, combustion quality, and the formation of emissions. The main geometry parameters such as plunger diameter and the number and diameter of nozzles lead to the system complexity, requiring careful analysis, design, and calibration. In this study, a high-speed shadowgraph system and a high-resolution pressure recording system were developed to capture the start of injection, spray structure, and pressure profiles in the high-pressure line. Additionally, a model was developed using GT-Fuel package built within the GT-Suite of simulation tools to explore different plunger diameters and numbers and diameters of injector nozzles. These models were validated using the pressure profiles, fuel quantity, and start of injection timing obtained from the experiments. This approach can either individually analyze the influence of each parameter or assess their overall impact. The results indicate that an increase in plunger diameter advances the start of injection (SOI). Furthermore, an increase in the number and/or diameter of nozzles results in a higher amount of fuel delivered per cycle. Overall, replacing an injection system with 10 mm plungers and injectors with 7 × 250 μm nozzles with one featuring 12 mm plungers and injectors having 8 × 300 μm nozzles can increase the fuel delivery by 1.85 fold. This approach could be useful for practical applications, including turbocharging engines and/or designing more efficient fuel systems. Future investigations into the high-speed shadowgraph images captured in this study could offer additional insights into the Rayleigh–Taylor and Kelvin–Helmholtz models concerning the primary and secondary atomization processes.</div></div>
The Effect of Cooling-Air Flow Conditions on the Thermal State of High-Pressure Nozzle Blade Manh D. Vu, Kien T. Nguyen, Thang T. Dao Proceedings of 2019 International Conference on System Science and Engineering Icsse 2019, 2019 Developing technique utilized for cooling turbine blades plays an important role in designing as well as manufacturing Gas Turbine Engine (GTE). This may enhance the GTE's lifetime and decrease its fuel consumption. The paper numerically examines the effect of cooling-air mass flow rate and other flow conditions including temperature and pressure on the thermal state of high-pressure nozzle blade of the DR 76 gas turbine engine.
