Jin‐Hyuk Kim

Multiphase pumps for offshore plants must perform at high pressure because they are installed on deep-sea floors to pressurize and transfer crude oil in oil wells. As the power for operating pumps should be supplied to deep sea floors using umbilicals, risers, and flow lines (URF), which involve a higher cost to operate pumps, the improvement of pump efficiency is strongly emphasized. In this study, a design optimization to improve the hydrodynamic performance of multiphase pumps for offshore pl

Lithium-ion batteries (LIBs) are undeniably the most promising system for storing electric energy for both portable and stationary devices. A wide range of materials for anodes is being investigated to mitigate the issues with conventional graphite anodes. Among them, TiO2 has attracted extensive focus as an anode candidate due to its green technology, low volume fluctuations (<4%), safety, and durability. In this review, the fabrication of different TiO2 nanostructures along with their electroc

Abstract Energy storage is an idea that dates back over two thousand years. Engineers, investors, and politicians are increasingly researching energy storage solutions in response to growing concerns about fossil fuels' environmental effects as well as the capacity and reliability of global power systems. Various energy storage technologies are explored in depth in this study, with a focus on their application to the energy storage of electric grids. Specific consideration is paid to a few chose

This paper presents the design optimization of a centrifugal compressor impeller with a hybrid multi-objective evolutionary algorithm. Reynolds-averaged Navier—Stokes (RANS) equations are solved with the shear stress transport turbulence model as a turbulence closure model. Flow analysis is performed on a hexahedral grid through a finite-volume solver. Two objectives, viz., the isentropic efficiency and the total pressure ratio (PR), are selected with four design variables that define the impell

Hydrodynamic analysis and an optimization of a vaned diffuser in a mixed-flow pump are performed in this work. Numerical analysis is carried out by solving three-dimensional Reynolds-averaged Navier-Stokes equations using the shear stress transport turbulence model. A validation of numerical results is conducted by comparison with experimental data for the head, power, and efficiency. An optimization process based on a radial basis neural network model is performed with four design variables tha

This paper presents an optimization procedure for axial-flow ventilation fan design through a hybrid multiobjective evolutionary algorithm (MOEA) coupled with a response surface approximation (RSA) surrogate model. Numerical analysis of a preliminary fan design is conducted by solving three-dimensional (3-D) Reynolds-averaged Navier-Stokes (RANS) equations with the shear stress transport (SST) turbulence model. The multiobjective optimization processes are performed twice to understand the coupl

A multidisciplinary optimization to simultaneously enhance the aerodynamic and aeroacoustic performance of an axial-flow fan was performed. Flow analysis through the axial-flow fan was conducted by solving three-dimensional steady and unsteady Reynolds-averaged Navier–Stokes equations with the shear-stress transport turbulence model. Starting with the results for the unsteady flow, aeroacoustic analysis was performed by solving the Ffowcs Williams–Hawkings equations. A single-objective optimizat

Most multi-phase pumps used in crude oil production have been developed to satisfy certain pressure specifications. In the design of these pumps, the flow characteristics of the posterior stage are different from those of the prior stage. For this reason, the design of the second stage needs to be supplemented. To optimize performance in this stage, multi-objective optimization to simultaneously increase pressure and efficiency is reported in this article. Flow analyses of the single and multipl

This paper presents an optimization procedure for high-efficiency design of a mixed-flow pump. Optimization techniques based on a weighted-average surrogate model are used to optimize a vane diffuser of a mixed-flow pump. Validation of the numerical results is performed through experimental data for head, power and efficiency. Three-level full factorial design is used to generate nine design points within the design space. Three-dimensional Reynoldsaveraged Navier-Stokes equations with the shear

This paper presents an experimental study on the low-velocity impact localization of complex composite structures. An impact localization algorithm, which localizes an impact source by comparing the normalized cross-correlation between the reference database and the obtained impact signals, was proposed. The proposed method was applied to a stiffened composite panel that consists of a main spar and stringers. Impact tests were conducted on the composite panel in which four multiplexed fiber Brag

Gene expression analyses by probes of hybridization from mRNA to cDNA targets arrayed on membranes or activated glass surfaces have revolutionized the way of profiling mega level gene expression. The main remaining problems however are sensitivity of detection, reproducibility and data processing. During processing of microarray images, especially irregularities of spot position and shape could generate significant errors: small regions of signal spots can be mis-included into background area an