• Journal of Mechanical Science and Technology
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• v.20 no.5
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• pp.681-691
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• 2006

Nucleate boiling heat transfer for refrigerants, R113, and R113+wt4% ethanol mixture, an azeotropic mixture under electric field was investigated experimentally in a single-tube shell/ tube heat exchanger. A special electrode configuration which provides a more uniform electric field that produces more higher voltage limit against the dielectric breakdown was used in this study. Experimental study has revealed that the electrical charge relaxation time is an important parameter for the boiling heat transfer enhancement under electric field. Up to 1210% enhancement of boiling heat transfer was obtained for R113+wt4% ethanol mixture which has the electrical charge relaxation time of 0.0053 sec whereas only 280% enhancement obtained for R113 which has relaxation time of 0.97 sec. With artificially machined boiling surface, more enhancement in the heat transfer coefficient in the azeotropic mixture was obtained.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.113.1-113.1
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• 2007

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.187.1-187
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• 1999

• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.113-113
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• 2007

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.12 no.2
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• pp.113-120
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• 2012

In this paper we study various properties of the fuzzy linear maps over the fuzzy quotient spaces. In particular we obtain some exact sequences of the fuzzy linear maps over the fuzzy quotient spaces.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.113-113
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• 2008

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.113.2-113.2
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• 2007

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.9
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• pp.1239-1246
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• 2000

The objective of this work is to measure space and time resolved wall heat fluxes during nucleate pool boiling of R113/R11 mixtures using a microscale heater array in conjunction with a high speed CCD. The microscale heater array is constructed using VLSI techniques, and consists of 96 serpentine platinum resistance heaters on a transparent quartz substrate. Electronic feedback circuits are used to keep the temperature of each heater at a specified temperature and the variation in heating power required to keep the temperature constant is measured. Heat flux data around an isolated bubble are obtained with triggered CCD images. CCD images are obtained at a rate of 1000frames/second. The heat transfer variation vs. time on the heaters directly around the nucleation site is plotted and correlated with images of the bubble obtainedby using the high speed CCD. For both of the mixture(R11/R113) and pure system(pure R11, pure R113), the wall heat fluxes are presented and compared to find out the qualitative difference between pure and binary mixture nucleate boiling.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.6
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• pp.750-756
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• 1998

In this study, condensation tests were conducted on a vertically finned plate (fin height 1 mm, fin thickness 1 mm, fin spacing 1 mm) using R-113. Results showed that fins enhanced the condensation on a vertical plain surface as much as four times. Comparison with theoretical models revealed that the effect off surface tension should be included in the model. The effect of interruption plates was also investigated. The plates were not effective in enhancing the finned plate condensation. The reason may be attributed to the already thinned condensate film on the finned surface.

• Journal of Advanced Marine Engineering and Technology
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• v.10 no.4
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• pp.67-77
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• 1986

The information on the heat transfer characteristics, flow pattern and pressure drop, are very important for the desing of general heat exchanger, refrigerating system, air conditioning system and energy recovery system. In these systems, water or lubricating oil contained in working fluid affects greatly the flow and heat transfer condition and this phenomena must be considered in the practical design. An experiment has been performed for studying the flow and heat transfer characteristics of the forced convective horizontal flow of R-113 under the range of the liquid single phase state to the boiling flow state. Basic experimental results are obtained in the case that water or lubricating oil does not contaminate in the test fluid. Experimental results are as follows; (1) The local heat transfer coefficients in the nucleate boiling region and transition boiling region are almostly ten times as large as that of liquid single phase flow. (2) The measured heat transfer coefficient in the present experimental range is relatively agreed well with the predicted value from the various experimental results for the boiling flow.