• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.343-349
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• 2007

This cryogenic miniature globe valve is used to transfer the liquified natural gas which temperature is $-169^{\circ}C$, supplied pressure is 30bar(3.0MPa). In the present work the temperature distribution and thermal deformation is calculated numerical the FE method is useful to predict the thermal matter of cryogenic miniature globe valve. For this reason, to optimum design of the cryogenic miniature globe valve the analysis of the parameter about bonnet has been studied. It's used 3-D modeling to analyze cryogenic globe valve, which is 1/2". Numerical study used 3-D modeling makes a decision of efficient process of product before producing in the factory. A commercial software(ANSYS 10.0) is used in the structural analysis for cryogenic globe valve.

• Journal of Mechanical Science and Technology
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• v.15 no.1
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• pp.26-34
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• 2001

Most research to date concerning the cryogenic toughness of austenitic stainless steels has concentrated on the base metal and weld metal in weldments. The most severe problem faced on the conventional austenitic stainless steel is the thermal aging degradation such as sensitization and carbide induced embrittlement. In this paper, we investigate the cryogenic toughness degradation which can be occurred for austenitic stainless in welding. The test materials are austenitic stainless JN1, JJ1 and JK2 steels, which are materials recently developed for use in nuclear fusion apparatus at cryogenic temperature. The small punch(SP) test was conducted to detect similar isothermally aging condition with material degradation occurred in service welding. The single-specimen unloading compliance method was used to determine toughness degradation caused by thermal aging for austenitic stainless steels. In addition, we have investigated size effect on fracture toughness by using 20% side-grooved 0.5TCT specimens.

• Transactions of Materials Processing
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• v.17 no.2
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• pp.102-106
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• 2008

Cryogenic rolling combined with warm rolling has been found more effective than a single cryogenic rolling process in improving the strength of a 5052 Al alloy. In this study, cryo-rolled 5052 Al alloys were warm-rolled at $175^{\circ}C$. A notable increase of tensile strength was achieved by the precipitation during warm rolling process. Mechanical behavior of this alloy was investigated using hardness and tensile tests. It was found that the cryogenic rolling process combined with warm rolling process was very effective in improving tensile strength.

• Progress in Superconductivity and Cryogenics
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• v.20 no.4
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• pp.11-15
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• 2018

Torque tubes in High Temperature Superconducting (HTS) motor transfer torque from superconducting field winding rotor to the room temperature shaft. It should have minimum heat conduction property for minimizing the load on cryo-refrigerator. Generally, these torque tubes are made with stainless steel material because of high strength, very low outgassing and low thermal contraction properties at cryogenic temperatures and vacuum conditions. With recent developments in composite materials, these torque tubes could be made of composites such as Kevlar and S-Glass, which have the required properties like high strength and low thermal conductivity at cryogenic temperatures, but with a reduced weight. Development and testing of torque tubes made of these composites for HTS motor are taken up at Bharat Heavy Electricals Limited (BHEL), Hyderabad in collaboration with Central Institute of Plastics and Engineering Technology (CIPET), Chennai and Indian Institute of Technology (IIT), Kharagpur. As these materials are subjected to vacuum, it is important to measure their outgassing rates under vacuum conditions before manufacturing prototype torque tubes. The present study focusses on the outgassing characteristics of Kevlar and S-Glass, using an Outgassing Measurement System (OMS), developed at IIT Kharagpur. The OMS facility works under vacuum environment, in which the test samples are exposed to vacuum conditions over a sufficient period of time. The outgassing measurements for the composite samples were obtained using pressure-rise technique. These studies are useful to quantify the outgassing rate of composite materials under vacuum conditions and to suggest them for manufacturing composite torque tubes used in HTS motors.

• Journal of Mechanical Science and Technology
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• v.20 no.7
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• pp.972-980
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• 2006

In general, to send out natural gas via a pipeline network across the nation in LNG terminal, high-pressure cryogenic pump supply highly compressed LNG to high-pressure vaporization facilities. The Number of cryogenic pumps determined the send-out amount in LNG receiving terminal. So it is main equipment at LNG production process and should be maintained on best conditions. In this paper, to find out the cause of high vibration at cryogenic pumps-motor system in LNG terminal, vibration spectrum analysis and motor current signature analysis have been performed together. Through the analysis, motor rotor bar problems are estimated by the vibration analysis and confirmed by the current analysis. So, it is demonstrated through the case study in this paper, how performing vibration analysis and current signature analysis together can reliable diagnosis rotor bar problems in pump-motor system.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.4
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• pp.247-251
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• 2017

Titanium alloy has been widely used in the aerospace industry because of its high strength and good corrosion resistance. During cutting, the low thermal conductivity and high chemical reactivity of titanium generate a high cutting temperature and accelerates tool wear. To improve cutting tool life, cryogenic machining by using a liquid nitrogen (LN2) jet is suggested. In cryogenic jet cooling, evaporation of LN2 in the tank and transfer tube could cause pressure fluctuation and change the cooling rate. In this work, cooling uniformity is investigated in terms of liquid nitrogen jet pressure in cryogenic jet cooling during titanium alloy turning. Fluctuation of jet spraying pressure causes tool temperature to fluctuate. It is possible to suppress the fluctuation of the jet pressure and improve cooling by using a phase separator. Measuring tool temperature shows that consistent LN2 jet pressure improves cryogenic cooling uniformity.

• Journal of the Semiconductor & Display Technology
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• v.20 no.2
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• pp.19-24
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• 2021

As the size of semiconductor devices decreases, the etching pattern becomes very narrow and a deep high aspect ratio process becomes important. The cryogenic etching process enables high aspect ratio etching by suppressing the chemical reaction of reactive ions on the sidewall while maintaining the process temperature of -100℃. ESC is an important part for temperature control in cryogenic etching equipment. Through the cooling path inside the ESC, liquid nitrogen is used as cooling water to create a cryogenic environment. And since the ESC directly contacts the wafer, it affects the temperature uniformity of the wafer. The temperature uniformity of the wafer is closely related to the yield. In this study, the cooling path was designed and analyzed so that the wafer could have a uniform temperature distribution. The optimal cooling path conditions were obtained through the analysis of the shape of the cooling path and the change in the speed of the coolant. Through this study, by designing ESC with optimal temperature uniformity, it can be expected to maximize wafer yield in mass production and further contribute to miniaturization and high performance of semiconductor devices.

• Food Engineering Progress
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• v.21 no.4
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• pp.391-402
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• 2017

The purpose of this study was to improve the nutrition and the permeability of functional plants by using cryogenic grinding technology. Barley sprouts, Curcuma longa L., Dendropanax morbifera LEV., Phellinus linteus were dried, ground and extracted in different temperature conditions. Powder size of barley sprouts and Curcuma longa L. were about $50{\mu}m$ and Dendropanax morbifera LEV. and Phellinus linteus were about $20{\mu}m$. Cryogenic ground of Barley sprouts preserved 18.27-124.65% of nutrients such as protein, ash, carbohydrate, beta carotene, minerals, vitamins. Cryogenic grinding powder of Curcuma longa L. show high nutrients retention rate of lipid and carbohydrate. Permeability was measured by Parallel Artificial Membrane Permeability Assay (PAMPA) to predict passive gastrointestinal absorption. Permeability of saponarin, which is marker compound of Barley sprouts, is 9.88 times higher in cryogenic grinding powder than ambient grinding powder. Curcumin permability is 3.1 times higher than ambient grinded powder. As a result, particle size, nutrition, protein digestion degree and permeability demonstrated a positive relationship with the decreasing grinding temperature for the powders. These results confirm that the cryogenic grinding method had good suitability to increase functionality of plants, since it could minimize the heat generated while processing and effectively reduce the particle size.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.3
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• pp.9-15
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• 2017

This study represents basic research for the development of submerged pump technology applicable to transfer and storage of a cryogenic liquids. Its purpose is to secure baseline design data by applying reverse engineering to the process of developing a submerged cryogenic pump. The two-stage model included in the ARTICK Series LNG Submerged Pump produced by Vanzetti of Italy was selected for analysis for development of a localized product, and was disassembled for reverse engineering. The pump was disassembled after analyzing its processing/assembly characteristics such as shrinkage of fittings. In addition, the materials used in manufacturing of the main components were analyzed, and the ingredients were confirmed. As a result, a design drawing for each component required for product development was secured via foundational design, and a test product was manufactured by maximizing the application of appropriate domestic technologies.

• Progress in Superconductivity and Cryogenics
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• v.18 no.2
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• pp.42-47
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• 2016

A free-piston reciprocating expander is a device which operates without any mechanical linkage to a stationary part. Since the motion of the floating piston is only controlled by the pressure difference at two ends of the piston, this kind of expander may indispensably require a sophisticated active control system equipped with multiple valves and reservoirs. In this paper, we have suggested a novel design that can further reduce complexity of the previously developed cryogenic free-piston expander configuration. It is a simple replacement of both multiple valves and reservoirs by a combination of an orifice valve and a reservoir. The functional characteristic of the integrated orifice-reservoir configuration is similar to that of a phase controller applied in a pulse tube refrigerator so that we designate the one as a phase controller. Depending on the orifice valve size in the phase controller, the different PV work which affects the expander performance is generated. The numerical model of this unique free-piston reciprocating expander utilizing a phase controller is established to understand and analyze quantitatively the performance variation of the expander under different valve timing and orifice valve size. The room temperature experiments are carried out to examine the performance of this newly developed cryogenic expander.