• Journal of Advanced Marine Engineering and Technology
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• v.11 no.3
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• pp.53-60
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• 1987

Steam ejector is a equipment which compresses the gases to desired discharge pressure. It is widely used for the evacuation systems because of its high working confidence. And recently it is used as the thermo-compressors in the various energy saving systems. Steam ejector is constructed of three basic parts; a suction chamber, a motive nozzle and a diffuser. The high velocity stream jet of steam emitted by the motive nozzle creats suction chamber, which draws the low pressure gases. The diffuser converts the kinetic energy of high velocity flow to pressure energy. It is not easy to determine the dimensions of a steam ejector met to the desired design condition, because that the expected suction rates must be obtained by reapeating the complicate calculation. And also such a calculation is concomitant with geometrical analysis for suction part and diffuser based on the stability of steam flow. Therefore, it is considered that the Computer-Aided Design (CAD) of steam ejector is a powerful design method. In this paper, computer program for steam ejector design is developed based on the theoretical research and the previous experimental results. And the determinating method of diffuser inlet angle and the velocity development profile of suction gas along to the diffuser are suggested. The validity of the development profile of suction gas along to the diffuser are suggested. The validity of the developed computer results with other's for the practical design calculation of a manufactured steam ejector.

• Knowledge Management Research
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• v.19 no.2
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• pp.21-45
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• 2018

With the widespread use of smartphones and the development of information technology, an online service called SNS(social network service) has emerged, and as an increasing number of people began to use SNS, extensive research has been conducted on SNS. SNS is an important factor for adolescents who are developing social skills that help them to adapt to the society, and for adults who are stepping into the society. The present study investigates the effects of information search, self-disclosure, interaction, and playfulness, all of which are motivational factors for SNS use, on flow in SNS, and empirically analyzes the degree of these variables influence according to flow in SNS and individual's personal nature(extrovert, introvert). The analysis results showed that information search, self-disclosure, interaction, and playfulness were positively correlated with flow in SNS, and flow in SNS was positively correlated with social skills. The degree of influence varied depending on the individual's personal nature(extrovert, introvert). These findings may provide important insights for researchers studying SNS, SNS managers, and company officials using SNS.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.993-1001
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• 2001

Experimental investigation on the performance of dual-evaporator refrigeration system with an ejector has been carried out. In this study, a hydrofluorocarbon (HFC) refrigerant R134a is chosen as a working fluid. The condenser and two-evaporators are made as concentric double pipes with counter-flow type heat exchangers. Experiments were performed by changing the inlet and outlet temperatures of secondary fluids entering condenser, high-pressure evaporator and low-pressure evaporator at test conditions keeping a constant compressor speed. When the external conditions (inlet temperatures of secondary fluid entering condenser and one evaporator) are fixed, results show that coefficient of performance (COP) increases as the inlet temperature of the other evaporator rises. It is also shown that the COP decreases as the mass flaw rate ratio of suction fluid to motive fluid increases. The COP of dual-evaporator refrigeration system with an ejector is superior to that of a single-evaporator vapor compression system by 3 to 6%.

• Survey Research
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• v.3 no.2
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• pp.17-45
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• 2002

The purpose of this study is to examine the effect of the Flow experience on purchase intention. The results of this study show that (1) the purchase intention through internet is increased in proportion to the degree of cognition of users' experience. (2) The "Flow" experiences during the time of navigating internet shopping-mall sites lead to different results due to the separate motive of searching internet shopping-mall sites. (3) It should analyze the market segmentation of internet users, using Flow experience in the future based on the relationship between Flow and on-line and off-line purchase intention. (4) Finally, it should study more profoundly on "experiential" Flow and "goal-directed Flow that it has to analyze the difference in Flow experiences between separate purposes of searching internet shopping-mall sites.

• Proceedings of the Technology Innovation Conference
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• 1999.12a
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• pp.296-327
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• 1999

Nowadays, there is a huge need of an extensive study to understand features and behavior modes of consumers who have an indefinite potential of purchase and to make EC a bullish market, Recently, the flow construct has been proposed as important for understanding consumer behavior on the cyber space. The purpose of this study is threefold. To investigate (1) the effect of the flow experience when navigating Internet shopping-mall sites and Internet on purchase intention and relational factors of this (2) the difference in the flow experiences between during the time of navigating Internet and during the time of navigating Internet shopping-mall sites. (3) the difference in purchase intention and relational factors of this between an experiential flow and a purposeful flow. The results show that (1) increase of the purchase intention on EC (or relational factors of this) in proportion to the degree of cognition of users' flow experience (2) By the separate motive of searching Internet shopping-mall sites, the flow experiences during the time of navigating Internet lead to different results (3) Although the difference in the purchase intention on EC between subjects is nonsignificant, it suggests that we need to focus on the fact that the correlation between the purchase intention on EC and the purposeful flow experience on Internet shopping-mall sites is greater than any other correlation. In the end of this study, The theoretical and practical implications of the study, limitations of the study, and future research implications are discussed.

• Journal of the Korean Society of Fashion and Beauty
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• v.5 no.1 s.12
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• pp.51-55
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• 2007

These days, hair design is recognized as a kind of molding arts which peform expression skill to create personal self as well as practical skill. Recently, the efforts to express hair design sublimating it to art works have continued. For these reasons, this study had purposes as follows; First, it developed creative and original design producing works to shape the flower image that was an important material of hair design. Second, it presented the possibility to express the field of hair design with art. In the flow of age, nature has provided design with unlimited creative motive. Flowers, among various materials, show the nature's change, combination and order and impose diverse symbolic meanings. Therefore, flowers are good materials to express the works. Through the process of decolorizing and dyeing with hair, five works of nature's fragrance, hope, reed flowers, windflower, magnolia blossom had been produced. The results of the process were as follows; First, the transformation of shape through the simple process taking the image of shaping flower as subject matter could be a motive of new hair design art. Second, if the various images of flowers were expressed as hair art with three-dimensional shape, it could be works with value of beauty. Through the process of this study, it was proved that nature could be endless subject matter for art. Therefore, with continuous studies, it can be motive of developing designs in producing work activities of many hair designers. In addition, academic development will be achieved through wide and diverse studies.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.155-158
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• 2002

In general, TVC(Thermal Vapor Compressor) is used to boost/compress a low pressure vapor to a higher pressure for further utilization. The one-dimensional method is simple and reasonably accurate, but cannot realize the detail as like the back flow and recirculation in the mixing chamber, viscous shear effect, and etc. In this study, the axisymmetric How simulations have been performed to reveal the detailed flow characteristics for the various ejector shapes. The Navier-Stokes and energy equations are solved together with the continuity equation In the compressible flow fields. The standard $k-{\epsilon}$ model is selected for the turbulence modeling. The commercial computational fluid dynamic code FLUENT software is used for the simulation. The results contain the entrainment ratio under the various motive, suction and discharge pressure conditions. The numerical results are compared with the experimental data, and the comparison shows the good agreement. The three different flow regimes (double chocking, single chocking and back flow) have been clearly distinguished according to each boundary pressure values. Also the effects of the various shape variables (nozzle position, nozzle outlet diameter, mixing tube diameter, mixing tube converging angle, and etc.) are quantitatively discussed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.281-286
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• 2004

The vacuum cleaner motor runs on very high speed for the suction power. Specially, the motive power is provided by the impeller being rotate on very high speed. And centrifugal fan consists of the impeller, the diffuser, and the circular casing. Due to the high rotating speed or the impeller and small gap distance between the impeller and diffuser, the centrifugal fan makes very high noise level at BPF and harmonic frequencies. In order to calculate the sound pressure of centrifugal fan, the unsteady flow data is needed. And Noise cause is dividing to fluid noise by exhaust flow of fan and vibration noise by rotational vibration of vacuum cleaner fan motor. Until now, measuring method has been used to measure vibration by the accelerometer; this method has been not measured for the vibration in some parts of brush and commutator because of motor construction and 3-D vibrating mode. This paper was purposed on the accurate analysis, using laser vibration analyzer,. By using this measured data of noise cause against the difficult part in old times, we would like to use for the design of silent fan motor.

• The KSFM Journal of Fluid Machinery
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• v.8 no.6 s.33
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• pp.33-39
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• 2005

A thermal vapor compressor in which the subsonic/supersonic flow appears simultaneously, has been accurately designed through the CFD analysis for the various shape parameters such as the primary nozzle shape, converging duct shape, mixing tube diameter, and so on. The performance of the developed thermal vapor compressor has been experimentally verified to be installed in a Multi Effect Desalination(MED) plant as an important element. In this paper, the effects of each parameter are discussed on the basis of CFD results and the experimental results for various boundary conditions(motive pressure, suction pressure, and discharge pressure) are presented in compared with CFD results. The two results show a good agreement with each other within 2 % accuracy with regard to the entrainment ratio.

• The KSFM Journal of Fluid Machinery
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• v.20 no.2
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• pp.26-31
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• 2017

In the present study, 20 kW turbine for OTEC with a ejector and a motive pump is designed and performance prediction is implemented by means of CFD. The meridional analysis for initial geometry and CFD for detail design are used to design the turbine. This turbine has about 90.9% efficiency and 28.47 kW power at 15,000 rpm and pressure ratio of 1.53. Homogeneous mixture model is used because two phase flow can be occurred in the turbine. Performance evaluation is carried out and then results are presented by plotting of power, mass flow rate and efficiency as varying pressure ratio and rotational speed.