• Journal of Environmental Science International
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• v.13 no.3
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• pp.223-232
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• 2004

The change of pressure drop according to the change in the inlet concentration, pulse interval, and injection distance of pulse air jet type bag filters, and the effect of venturi installation are as follows. The pressure drop with the range of 30 to $50mmH_2O$ varies according to the injection distance with 30, 50, 70, 90sec and the inlet concentration of venture built-in fabric filters. For the lower concentration of 0.5g/㎥ and 1g/㎥, the pressure $drop(\DeltaP)$ was stable 60 to 90minutes after operation. For the higher concentration of 3g/㎥, as $\DeltaP$ continues to go up, pulse interval should be set shorter than 30 seconds. The pressure drop with the injection distance of 1l0mm, when inlet dust concentration is 0.5g/㎥ or 1g/㎥, is 1.3 to 2 lower than with the injection distance of 50, 160, and 220mm, which means that the inflow amount of the secondary air by the instant acceleration is large. The injection distance of 2g/㎥ and 3g/㎥ has the similar pressure distribution. The higher inlet concentration is, the more important pulse interval is than injection distance. The pressure drop has proved to be larger when inlet concentration is lower and injection distance closer, on condition that the venturi is installed. The change in the pressure drop was smallest when injection distance was 50mm, followed by 220mm, 160mm, and 110mm.

• Journal of ILASS-Korea
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• v.8 no.4
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• pp.17-23
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• 2003

To find suitable injection pressure, ultra high pressure impinging spray characteristics were investigated with a impinging distance and a impinging angle by using high pressure injection system. As impinging distance was increased, spray penetration was decreased but spray height was increased. For increase of injection pressure, spray penetration and spray height were increased until 2,500bar. But over this injection pressure region, the rate of increase was decreased suddenly.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.61-68
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• 2002

Combustion characteristics of dual transverse injection of hydrogen in supersonic air flows were studied using computational methods. Three-dimensional Navier-Stokes with a non-equilibrium chemical reaction model and the k-$\omega$ SST turbulence model were used. A parametric study was conducted with the variation of the distance between two injectors. Combustion characteristics of dual injection are very different from those of single injection. The combustion characteristics of two injection flows are very different from each other, and the ignition and combustion characteristics of the rear injection flow are strongly influenced by those of the front injection flow. The increase of the distance between two injectors up to a specific distance results in the increase of burning rate. However, the increase of the distance over the specific distance gives no increase of burning rate but makes more losses of stagnation pressure. From the results it can be stated that there exists a distance between two injectors for optimum combustion characteristics.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.12
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• pp.1021-1030
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• 2016

The runner system of the injection mould and the injection volume of the injection molding process greatly affect the quality of the produced part. The goal of this paper is the design of the runner system and the prediction of the injection volume for the injection moulding of a housing part of small-size air cleaner to improve the formability through the three-dimensional injection moulding analysis. The effects of the runner system of the mould on the injection moulding characteristics are investigated. From the results of the investigation, a proper design of the runner system with uniform filling characteristics and the minimized defect formation is obtained. In addition, the influence of the moving distance of the screw on filling characteristics, weldline formation and deformation characteristics is examined. From the results of the examination, an appropriate moving distance of the screw for the housing part of small-size air cleaner is estimated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.53-60
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• 2002

Based on the analyses of the single transverse injection in supersonic flow fields, the mixing characteristics of dual transverse injection of hydrogen in supersonic air flow are studied with computational methods. Three-dimensional Navier -Stokes and the k-$\omega$ SST turbulence model were used. A parametric study is conducted with the variation of the distance between two injectors. The flow patterns and the mixing characteristics of two injection flows are very different from each other, and the flow patterns and the mixing characteristics of the rear injection flow are strongly influenced by those of the first injection flow. The increase of the distance between two injectors up to a specific distance results in the increase of mixing rate and penetration of fuel. However, the increase of the distance over the specific distance results in the decrease of mixing rate and penetration of fuel. From the results it can be stated that there exists a distance between two injectors for optimum mixing characteristics.

• Journal of ILASS-Korea
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• v.10 no.1
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• pp.17-23
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• 2005

Even though a relatively complete knowledge base has been established for diesel sprays, much of the knowledge cannot be directly translated to correlate the characteristics of gasoline spray. The macroscopic characteristics of gasoline impingement spray was investigated with photographic and image processing technique by Particle Motion Analysis System. The injector with single hole nozzle diameter of 0.28 mm was used in this experiment and the injection duration was selected as 10 msec. The injection pressure with 0.3, 0.35, and 0.4 MPa, impingement distance or 70, 100 and 130m, impingement angle or 0.15, 30 and $45^{\circ}$ were employed for the variables to affect the spray characteristics of impinging spray. It is clear that there is the analogy on the spray tip penetration between the gasoline impinging jet and diesel free jet. The spray tip penetration of impinging gasoline spray is proportional to the quarter power of the time after start of injection. The maximum height of impinging gasoline spray is also proportional to the quarter power of the time regardless of impingement distance, impingement angle and injection pressure. In addition, the effect of impingement angle on the spray tip penetration is significant according to the time after start of injection, even though there is minor effect in the initial stage of time after start of injection. Moreover, there is no remarkable effect of injection pressure on the spray tip Penetration under the experimental condition used in this study.

• Transactions of Materials Processing
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• v.20 no.1
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• pp.5-10
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• 2011

The main objective of the present study is to predict the process window of injection-compression molding corresponding to the capability of an injection machine for fabricating 7 inch LGP. The open distance and volume filled after injection stage were found to be two important factors that affect critical requirements such as flow length, injection pressure and clamping force for the process. Process window for the key factors was also predicted by response surface method. As a result, predicted process window for open distance and volume filled after injection stage satisfying the critical requirement with a given injection machine was in the range of 60 ~ 75%, and 104.00 ~ 104.25%, respectively.

• Journal of Environmental Science International
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• v.28 no.9
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• pp.737-749
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• 2019

In this study, the sensitivity analysis of hydraulic conductivity and separation distance (distance between injection well and pumping well) was analyzed by establishing a conceptual model considering the hydrogeologic characteristics of facility agricultural complex in Korea. In the conceptual model, natural characteristics (topography and geology, precipitation, hydraulic conductivity, etc.) and artificial characteristics (separation distance from injection well to pumping well, injection rate and pumping rate, etc.) is entered, and sensitivity analysis was performed 12 scenarios using a combination of hydraulic conductivity ($10^{-1}cm/sec$, $10^{-2}cm/sec$, $10^{-3}cm/sec$, $10^{-4}cm/sec$) and separation distance (10 m, 50 m, 100 m). Groundwater drawdown at the monitoring well was increased as the hydraulic conductivity decreased and the separation distance increased. From the regression analysis of groundwater drawdown as a hydraulic conductivity at the same separation distance, it was found that the groundwater level fluctuation of artificial recharge aquifer was dominantly influenced by hydraulic conductivity. In the condition that the hydraulic conductivity of artificial recharge aquifer was $10^{-2}cm/sec$ or more, the radius of influence of groundwater level was within 20 m, but In the condition that the hydraulic conductivity is $10^{-3}cm/sec$ or less, it is confirmed that the radius of influence of groundwater increases sharply as the separation distance increases.

• Journal of ILASS-Korea
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• v.9 no.4
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• pp.31-37
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• 2004

This paper presents spray and combustion characteristics of hydrocarbon fuel injected from pressure-swirl nozzles. Three commercial nozzles with orifice diameters of 0.256, 0.308 and 0.333mm and injection pressures ranging from 0.7 to 1.3 MPa were selected f9r the experiments. Spray characteristics such as breakup length. spray angle and drop size (SMD) were analyzed using photo image analyses and Malvern Panicle Size Analyzer. The drop size was measured with and without a blower at the same measuring locations. The flame length and width were measured using photo image analyses. The temperature distribution along the axial distance and the gas emission such as CO, $CO_2\;and\;NO_x$ were studied. The breakup length decreased with an increase in injection pressure for each nozzle but increased with an increase in nozzle orifice diameter. The spray angle increased and SMD decreased with an increase in injection pressure. The flame with an increased linearly with an increase in injection pressure and in nozzle orifice diameter. The flame temperature increased with an increase in injection pressure but decreased along the axial distance. The maximum temperatures occurred closer to the burner exit and flame at axial distance of 242mm from the diffuser tip. The experimental results showed that the level of CO decreased while that of $CO_2\;and\;NO_x$ increased with an increase in injection pressure and nozzle orifice diameter.

• Design & Manufacturing
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• v.15 no.3
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• pp.56-61
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• 2021

The increase in automation facilities in the injection molding industry is a very important process control item. The most important item when constructing an unmanned machine using a take-out robot is the "mold opening stroke" of the mold. The injection molding machine control method is divided into hydraulic type and electric type, and there have been few studies on the mold opening distance according to the control method. In this study, the correlation was confirmed by increasing the injection speed to 20, 50, 80, and 100% for the three types of hydraulic control method, open loop and close loop, and electric control method. Through the experiment, the following results were obtained. (1) It can be seen that the reproducibility is excellent with the electric, close loop, and open loop control methods. (2) When the injection speed is set to 50%, the mold opening distance is 263.10~263.27 mm, which is the most reproducible. (3) As a result of ANOVA, both injection speed and mold opening distance showed a significant difference in the hydraulic control method (p<0.05), but it was verified through experiments that there was no significant difference in the electric control method. Based on these results, when electric control is selected rather than hydraulic control, the reproducibility of the mold opening distance is excellent, so it is thought that the taking-out robot can take the object out of the mold more safely.