• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.1
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• pp.108-116
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• 2001

The vortex tube is a simple device which separates fluid stream into a cold stream and a hot stream without any chemical reaction. The process of energy separation in the vortex tube has caused a great deal of interest. Although many studies on energy separation in the vortex tube using air as the working fluid have been made so far, few experimental studies treated energy separation for incompressible fluid. So, an experimental study for the energy separation in the vortex tube using the water which is essentially an incompressible fluid is presented. When working fluid is the water, the best geometric values of nozzle area ratio and number of nozzle holes are 0.155, 6 respectively. These geometric values are showed by the similar values which are presented by compressible fluid as working fluid. But hot side mass fraction of which maximum temperature drop is happened are different from compressible fluid.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1149-1155
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• 2001

The experimental investigation on energy separation in a vortex tube has been carried out to sow the effect of inlet and outlet pressures with various working fluids(air,$O_2,\;and\; CO_2$). Those outlet pressure means cold outlet and hot outlet pressure which were set equally. The results showed that the total enthalpy variation became a maximum when the mass flow rate at the cold outlet was a half of the total mass flow rate in the vortex tube (y=0.5). The total enthalpy variation was quite affected by the pressure difference between the inlet and outlet of vortex tube when the ratio of the inlet pressure to the cold outlet pressure remained constant. Although specific enthalpy differences between the inlet and the outlet (both cold and hot outlet) did not noticeably vary with the pressure difference, the specific enthalpy difference between the inlet and cold outlet was dominantly affected by physical properties of working gases.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.51-56
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• 2007

Precision positioning system with magnetostrictive actuator(MA) has widely used in manufacturing devices to control the positioning accuracy to meet the high load and stroke requirements. It has many advantage in comparison with piezoelectric actuator; high force, high strain, high efficient etc. But, the performance of Terfenol-D, the commercially available magnetostrictive material, is highly dependent on the prestress, magnetic field intensity and temperature. This paper present an experimental investigation of the temperature effect on displacement characteristics of magnetostrictive actuator. In this paper, compressed cold air is proposed to improve of positioning accuracy of magnetostrictive actuator. The compressed cold air cooling system has good cooling effect Experimental results confirming the effectiveness of the proposed cooling system as high precision positioning system are also has presented in this paper.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.4
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• pp.388-394
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• 2009

Precision positioning system with magnetostrictive actuator(MA) has widely used in manufacturing devices to control the positioning accuracy to meet the high load and stroke requirements. It has many advantage in comparison with piezoelectic actuator; high force, high strain, high efficient etc. But, the performance of Terfenol-D, the commercially available magnetostrictive material, is highly dependent on the prestress, magnetic field intensity and temperature. Therefore, thermal strain of magnetostrictive material obstructs precision position control of magnetostrictive actuator, magnetostrictive actuator is need of cooling system. In this paper, cooling system using compressed cold air is developed and proper temperature and velocity of compressed cold air is studied by thermal analysis according to applied current.

• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.162-170
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• 1999

Numerical study has been peformed to develop a computer code for the design & optimal operating condition of SNCR(Selective Noncatalytic Reactor) for NOx reduction together with the analysis of the performance of vortex tube. Especially for the SNCR of the scale of industrial boiler, the required mixing and residence time of $NH_3$ solution was successfully tested numerically by the implementation of some baffle setups in a combustor. The introduction of interesting phenomena of vortex tube and similar system is made together with a theoretical hypothesis and simple cold flow simulation for the flow field analysis.

• Solar Energy
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• v.19 no.4
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• pp.1-10
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• 1999

The phenomena of energy separation through the vortex tube was investigated experimentally, to see the effect of nozzle area ratio and partial admission rate on the energy separation and cooling capacity. The experiment was tarried out with various nozzle area ratios from 0.031 to 0.232 and partial admission rate from 0.176 to 0.956 by varying input pressure($0.2{\si\m}0.5$ MPa) and cold air mass fraction($y=0.1{\sim}1.0$). From the experimental result, we found the optimum nozzle area ratio and the effective partial admission rate for the available use and best cooling performance in given operation condition. While the maximum drop of cold air temperature was observed at around y=0.3 and $S_n=0.155$, the maximum cooling capacity was observed at around y=0.6 and $S_n=0.094$.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.235-241
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• 2002

The process of energy separation in a low pressure vortex tube with air as a working medium is studied In detail. Experimental data of the temperature of the cold and hot air leaving the vortex tube are presented. The variation of the maximum wall temperature along the inner surface of the vortex tube and the temperature distribution in the vortex tube provides useful information about the location of the stagnation point of the flow field at the axis of the vortex tube. In this study Outer tube is used for the application of Diesel engine exhaust. The hot gas flow is fumed 180° and passes the outside of the vortex tube a second time heating it. From this geometric setup of a vortex tube the effects of energy separation and the prediction of the ignition of Diesel Soot is presented by experimental data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1005-1012
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• 2001

When vortex tubes are applied to enhance the coefficient of performance of refrigeration system, the smaller one is preferable. However, the existing vortex generator with a nozzle hole diameter of 0.5mm was not suitable due to chocking of the nozzle hole. Therefore, experimental investigation was made to find an appropriate geometry of vortex generator, which could give a comparable effect of energy separation to commercial ones without chocking problem. The tested vortex generators were tangential and spiral types, which had single inducing channel with larger cross-sectional area than that of conventional multi-hole ones. The experimental result showed that the performance of the spiral type was better than that of the tangential one. As a small size of spiral one, the diameter of cold-end orifice is proposed to an half of tube diameter for the application to refrigeration system, while cold mass fraction ratio is 0.5∼0.6 for a desirable operation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.3
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• pp.1061-1073
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• 1996

Vortex tube is a simple device which splits a compressed gas stream into a cold stream and a hot stream without any chemical reactions. The phenomena of energy separation taking place in a vortex tube has been investigated experimentally. Recently, vortex tube is widely used to local cooler of industrial equipments and air conditioner of special purpose. In this study, experimental study on vortex tube efficiency was performed with various cold end orifices and nozzles type. The experimental results indicate that there is an optimum diameter of cold end orifice and nozzle type for the best cooling performance. The variation of the maximum wall temperature along the vortex tube surface provides useful information about the location of the stagnation point of the flow field at the axis of the vortex tube. The similarity relation for the prediction of the temperature of the cold exit air was obtained.