Application of the Design of Experiments and Computational Fluid Dynamics to Bow Design Improvement

Donnan Membrane Process for the Selective Recovery and Removal of Target Metal Ions-A Mini Review

Membrane-based water purification technologies contribute significantly to water settings, where it is imperative to use low-cost energy sources to make the process economically and technically competitive for large-scale applications. Donnan membrane processes (DMPs) are driven by a potential gradient across an ion exchange membrane and have an advantage over fouling in conventional pressure driven membrane technologies, which are gaining attention. DMP is a removal, recovery and recycling technology that is commonly used for separation, purification and the concentrating of metals in different water and waste streams. In this study, the principle and application of DMP for sustainable wastewater treatment and prospects of chemical remediation are reviewed and discussed. In addition, the separation of dissolved metal ions in wastewater settings without the use of pressure driven gradients or external energy supply membrane technologies is highlighted. Furthermore, DMP distinctive configurations and operational factors are explored and the prospects of integrating them into the wastewater treatment plants are recommended.

The Effect of Hull Form Parameters on the Hydrodynamic Performance of a Bulk Carrier

In this study, the effect of joint optimization of the principal dimensions and hull form on the hydrodynamic performance of a bulk carrier was studied. In the first part of the joint optimization process, fast principal-dimension optimization of the origin parent ship considering the integrated performance of ship resistance, seakeeping, and maneuverability, as well as their relationships with the principal dimensions were analyzed in detail based on the ship resistance, seakeeping qualities, and maneuverability empirical methods of Holtrop and Mennen, Bales, and K and T indices, respectively. A new parent ship was chosen from 496 sets of hulls after comprehensive consideration. In the remaining part, a further hull form optimization was performed on the new parent ship according to the minimum wave-making resistance. The obtained results demonstrate that: (a) For the case in which the principal dimension of the original parent-type ship is different from that of the owner’s target ship, within the bounds of the relevant constraints from the owner, an excellent parent ship can be obtained by principal-dimension optimization; (b) the joint optimization method considering the principal dimension and hull form optimization can further explore the optimization space and provide a better hull.

Optimization Based on Product and Desirability Functions for Flow Distribution in Multi-Channel Cooling Systems of Power Inverters in Electric Vehicles

The onboard charger (OBC)/low-voltage DC-DC converter (LDC) integrated power inverter for electric vehicles comprises multiple electrical elements that can heat up, which can cause performance degradation and system instability issues in electric vehicles. To address this, a cooling system is included in the OBC/LDC integrated power inverter, which primarily uses water as a coolant. In this water cooling method, controlling the flow rate of water is critical for uniform cooling of the component. Thus, we propose an optimization method that helps determine the design variables to ensure uniform flow rate in each channel of the water-cooled system. The control variables for fluid-flux flow distribution optimization are selected by performing flow analysis for the initial design shape and analyzing their effects on fluid-flux flow distribution. For optimization analysis, the central composite design technique was applied; in addition, multi-response surface optimization using the same flow rate for each channel was performed. The optimization results were compared and verified using desirability functions based on the flow ratio of the cooling water channel, product function, and error function. Among single-response objective functions, the product function showed excellent performance. However, optimization using a multi-response objective function showed significantly higher prediction accuracy than the single-response function: using the optimized design obtained with the multi-response objective function improved the fluid-flux flow distribution uniformity by approximately 90% or more than the initial design.