• Clean Technology
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• v.14 no.1
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• pp.1-6
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• 2008

Removal of paraffin wax from a ceramic injection mold using supercritical $CO_2$ has been studied. The paraffin wax is used as a binder in the ceramic injection molding process. The effects of pressure, temperature and flow rate of supercritical $CO_2$ on the removal of the paraffin wax were investigated. The removal rates were measured with various flow rates of $CO_2$ in the range of 328.15 - 348.15 K and 15 - 30 MPa. The removal rate of paraffin wax increased as the pressure increased. In the effect of temperature, the paraffin wax was effectively removed over 329.15K (melting point of paraffin wax), however, the efffct of temperature was not significant when the temperature was further increased. The increase of $CO_2$ flow rate also affected the removal of paraffin wax. However, the effect of flow rate was not observed when the flow rate reached a certain value. Propane was used as a co solvent in order to remove the paraffin wax effectively. When the propane was added to the $CO_2$, the removal efficiency was improved. The paraffin wax was completely removed from the ceramic injection mold without any change in their shape and the structure.

• Economic and Environmental Geology
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• v.52 no.1
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• pp.37-48
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• 2019

In geological $CO_2$ sequestration, the behavior of $CO_2$ within a reservoir can be characterized as two-phase flow in a porous media. For two phase flow, these processes include drainage, when a wetting fluid is displaced by a non-wetting fluid and imbibition, when a non-wetting fluid is displaced by a wetting fluid. In $CO_2$ sequestration, an understanding of drainage and imbibition processes and the resulting NW phase residual trapping are of critical importance to evaluate the impacts and efficiencies of these displacement process. This study aimed to observe migration and residual trapping of immiscible fluids in porous media via cyclic injection of drainage-imbibition. For this purpose, cyclic injection experiments by applying n-hexane and deionized water used as proxy fluid of $scCO_2$ and pore water were conducted in the two dimensional micromodel. The images from experiment were used to estimate the saturation and observed distribution of n-hexane and deionized water over the course drainage-imbibition cycles. Experimental results showed that n-hexane and deionized water are trapped by wettability, capillarity, dead end zone, entrapment and bypassing during $1^{st}$ drainage-imbibition cycle. Also, as cyclic injection proceeds, the flow path is simplified around the main flow path in the micromodel, and the saturation of injection fluid converges to remain constant. Experimental observation results can be used to predict the migration and distribution of $CO_2$ and pore water by reservoir environmental conditions and drainage-imbibition cycles.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.63-74
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• 2001

In this study, a cycle simulation program of a Unit-Injection(UI) system was developed to estimate the injection performance of newly designed injection system. A fundamental theory of the simulation program is based on the conservation law of mass. Loss of fuel mass in the system due to leakage, compressibility effect of the liquid fuel and friction loss in the control volume was considered in the algorithm f the program. For the evaluation of the simulation program developed, the experimental result which was offered by the Technical Research Center of Doowon Precision Industry Co. was incorporated. Two main parameters; the maximum pressure in the plunger chamber and total fuel mass(kg) injected into the engine cylinder per cycle, were measured and compared with the simulation results. It was found that the maximum error rate of the simulation result to the experimental output was less than 3% in the rated rotational speed (rpm) range of the plunger cam.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.205-213
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• 2005

This study deals with the result of exhaust emissions and performance calculated by simulation of the fuel injection characteristics of the inline injection system in a marine diesel engine. The emissions are calculated through non-equilibrium by using the extended Zel'dovich kinetic mechanism for NOx and equilibrium method for OH, CO, $H_2$, Hand soot concentrations. Comparisons of the model predictions with the experimental values show reasonable agreement. Detailed prediction results showing the sensitivity of the model by injection rates are presented and discussed.

• Design & Manufacturing
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• v.11 no.1
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• pp.14-18
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• 2017

Recently, the injection-molded products are lighter, and thinner than ever. In this work, Injection molding simulation was conducted to analysis the filling pattern imbalance in high speed injection molding process for thin-wall injection component, 8 inches LGP. Numerical analysis shows that shear heated polymer near the side wall causes filling imbalance between center and side of cavity. Short shot experiments were conducted and compared with simulation results. Filling imbalance ratio showed a tendency to increase for wider fan gate.

• Journal of the Korean Society of Industry Convergence
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• v.10 no.4
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• pp.285-289
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• 2007

This study presents the preform injection molding of the injection stretch-blow molding process for PET bottles. The numerical analysis of the injection molding of a preform is considered in this paper using CAE with a view to minimize the warpage. In order to determine the design parameters and processing conditions in injection molding, it is very important to establish the numerical model with physical phenomenon. In this study, a three dimensional model has been introduced for the purpose and flow simulations of filling, post-filling and cooling process are carried out. The simulations resulted in the warpage in good agreement with the measurements. Also, from the result of numerical analysis, we appropriate -ly predicted the warpage, deformation and thickness distribution along the preform wall.

• Journal of ILASS-Korea
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• v.17 no.2
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• pp.57-63
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• 2012

For reduction of CO, NOx and soot emission emitted by diesel diffusion combustion, the authors focused on injection actuator to improve fuel availability inside combustion chamber. In this study, it was investigated the internal dynamic characteristics of two-stage injection with diesel injectors with different driving type for the common rail direct injection by using the AMESim simulation code. The analysis parameter defined such as fuel pressure, injection hole's diameter and driven voltage. As the results, it was shown that the piezo-driven injector had a faster response and had better control capability than the solenoid-driven injector. It was found the piezo-driven injector can be utilized effectively as multiple injector than solenoid-driven injector.

• Design & Manufacturing
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• v.12 no.2
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• pp.51-56
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• 2018

Generally, The women was used in the cosmetic cushion fact. It has developed with the consideration of manufacturing. In this study, we designed green-friendly and element parts lower and single cushion fact containers using a single material. Injection mold simulation were performed using on 3D design data. The injection mold simulation used the data (Injection time / Cooling time / Temperature / Pressure) in the injection mold parameters. In addition, the sink mark phenomenon in the simulation results is analyzed as a problem due to the thickness and further research is needed in the future.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.9
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• pp.109-115
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• 2008

The cleaning process of contaminant particles adhering to the microchips, integrated circuits (ICs) or the like is essential in modern microelectronics industry. In the cleaning process particularly working with the application of inert gases, the removal of contaminant particles of submicron scale is very difficult because the particles are prone to reside inside the boundary layer of the working fluid, The use of cryogenic $CO_2$ cleaning method is increasing rapidly as an alternative to solve this problem. In contrast to the merits of high efficiency of this process in the removal of minute particles compared to the others, even fundamental parametric studies for the optimal process design in this cleaning process are hardly done up to date, In this study, we attempted to measure the cleaning efficiency with the variations of some principal parameters such as mass flow rate, injection distance and angle, and tried to draw out optimal cleaning conditions by measuring and evaluating an effective cleaning width called $d_{50}$.

• Journal of computational fluids engineering
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• v.18 no.3
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• pp.20-25
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• 2013

In various manufacturing industries, an in-mold decoration (IMD) process for plastic objects is widely utilized because a film forming and an injection molding processes run simultaneously. In the present study, the deformation of polymer film and filling of resin in the IMD process were numerically investigated to evaluate the quality of the plastic object formed by the IMD process, which consists of thermoforming and injection molding processes. To obtain the initial shape of the polymer film during the injection molding process, the deformation of the polymer film in the thermoforming process was pre-formed using the vacuum conditions to attach the film to a cavity. Since the properties and deformation of polymer film are greatly affected by the behavior of polymer resin being injected into a mold cavity, numerical simulations for the injection molding and film forming were performed with one-way coupling method. The results showed that the injected resin could lead to the tearing of the polymer film in local regions near the corners. In order to verify the proposed numerical methodology, the numerical results of the deformation patterns printed on the initial polymer film were compared with the experimental data. The proposed methodology to couple film forming analysis with injection molding analysis can be used to predict the deformation of film in IMD process.