• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1220-1227
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• 2001

The condensation pressure drop fur refrigerant R-22 flowing in the plate and shell heat exchanger were investigated experimentally in this study. Two vertical counterflow channels were formed in the exchanger by three plates of commercial geometry with a corrugated trapezoid shape of a chevron angel of $45^{\circ}$. The condensing R-22 flowing down in one channel exchanges heat with the cold water flowing up in the other channel. The effects of the mean vapor quality, mass flux, average imposed heat flux and system pressure of R-22 on the pressure drop were explored in detail. The quality change of R-22 between the inlet and outlet of the refrigerant channel ranges from 0.03 to 0.05. The present data showed that pressure drop increases with the vapor quality. At a higher mass flux, pressure drop is higher for the entire range of the vapor quality. Also, a rise in the average imposed heat flux causes an slight increase in the Pressure drop. Finally, at a higher system pressure the pressure drop is found to be slightly lower. Correlation is also provided for the measured pressure drops in terms of the friction factor.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.930-938
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• 2001

In this study, evaporation pressure drop experiments were conducted with two types of plate and shell heat exchangers (P&SHE) using R-22. An experimental refrigerant loop has been established to measure the evaporation pressure drop of R-22 in a vertical P&SHE. The flow channels were formed by adding three plates having a corrugated channel of a chevron angle of $45^{\circ}$. The R-22 flows down in one channel exchanging heat with the hot water flowing up in the other channel. The effect of the refrigerant mass flux, average heat flux, system pressure and vapor quality were explored in detail. During the experiment, the quality change between the inlet and outlet of the refrigerant channel ranges from 0.03 to 0.15. The present data showed that two types of P&SHE have similar trends. The pressure drop increases with the vapor quality for both types of P&SHE. At a higher mass flux, the pressure drop is higher for the entire range of the vapor quality. Also, the increase in the average heat flux increases the pressure drop. Finally, at a higher system pressure, the pressure drop is found to be slightly lower.

• Korean Journal of Food Science and Technology
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• v.19 no.3
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• pp.195-199
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• 1987

Changes in quality characteristics of boiled-dried anchovy during storage under different packaging conditions for 6 months were studied. For the packaging trials, kraft paper (KP), kraft paper laminated with 0.03 mm polyethylene film (KP/PE) and 0.1 mm polyethylene film with nitrogen gas substitution ($N_2$ gas) were employed. In case of KP, the reaction of thiobarbituric acid, browning rate of lipid oxidation and Hunter color values of L, a and b were remarkably higher than those packaged in KP/PE or $N_2$ gas. Judging from organoleptic evaluation boiled-dried anchovy could be preserved in acceptable condition for 6 months at $5^{\circ}C$in all packaging cases and, at room temperature, 3 months in KP and 4 months in KP/PE or $N_2$ gas. From the standpoint of quality stability by packaging methods, it was concluded as good in sequence as $N_2$, gas, KP/PE and KP. The results suggest that the quality of boiled-dried anchovy be well preserved by packaging with inert gas ($N_2$ gas) or impermeable material to vapors and oxygens.

• Journal of Food Hygiene and Safety
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• v.2 no.1
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• pp.21-27
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• 1987

ABS1'RACT-Comparative effects of gamma irradiation and ethylene oxide treatment on the sterilization, and physicochemical and sensory quality of dried marine products(shrimp, anchovy) were investigated. Population of mesophilic total bacteria, aerobic spores and tolerant bacteria of samples were $10^{3}-10^{7}/g,\;10^{7}\;to \;10^{4}/g\;and\;10^{2}\;to\;10^{6}/g$, respectively. Coliforms and molds were found only in dried shrimp as $10^{2}/g$. Mesophilic total bacteria, aerobic spores and acid tolerant bacteria were reduced by over 2 to 4 log cycles with irradiation of 5 to 7 kGy and they were completely sterilized by irradiation dose of 7 to 10 kGy. $D_{10}$ value of mesophilic total bacteria of samples ranged from 1.53 to 2.73 kGy. Coliforms and molds were sterilized at 5 to 7 kGy irradiation but ethylene oxide treatment proved insufficient to eliminate the microorgainsms. An optimum dose of irradiation was less detrimental than ethylene oxide treatment to phpicochemical properties of the samples, such as the pH, TBA value, TMA-N, amino acids, minerals and color difference. Sensory quality after three months of storage showed that the overall acceptability of irradiated sample was higher than that of the non treated control as well as ethylene oxide treated samples.amples.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.3
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• pp.335-342
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• 1986

The feasibility of simultaneous measurement of gas-liquid tow-phase flowrate and quality with a sharp-edged orifice has been investigated. Instantaneous pressure drop curves were monitored for various combinations of gas and liquid flowrates in the bubbly flow regime and some statistical properties of the curves were calculated. The time-averaged value of pressure drop increases with increasing gas and liquid flowrate, whereas the mean amplitude and the intensity of fluctuation monotonically increase as void fraction becomes larger in the flow regime. The statistical furctions for the instantaneous curves indicate a consistent pattern throughout the flow regime and the probability density function, which as a single-peaked and symmetrical distribution, is well predicted by the Gaussian distribution function. The results indicate that simultaneous determination of two-phase flowrate and quality may be possible based upon the statistical analysis of instaneous pressure drop curves measured in a sharp-edged orifice.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.4
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• pp.460-469
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• 2010

In spite of the global-class aquaculture and fishing technology of our country, the processing technologies are lags behind the other nations relatively. The processed marine products are mainly frozen foods, canned goods, salty food (fermented fish products), fish paste products (boiled fish paste), and we can see that the high-value dehydrated foods by drying are very few. These problems are considered to be caused directly by the lack of drying technologies. This paper is concerned to the experimental results of drying heat transfer characteristics for the green energy type vacuum dryer for the high quality sea foods production.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.248-253
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• 2001

An experiment was carried out to investigate the characteristics of the evaporation heat transfer for refrigerant R-134a flowing in a plate and shell heat exchanger. The data are useful in designing more compact and effective evaporators for various refrigeration and air conditioning systems. Two vertical counterflow channels were formed in the exchanger. The R-134a flows up in one channel exchanging heat with the hot water flowing down in the other channel. The effects of the average heat flux, mass flux, saturation temperature and vapor quality were examined in detail. The present data show that the evaporation heat transfer coefficient increases with the vapor quality. A rise in the refrigerant mass flux causes an increase in the $h_r$ value. A rise in the average imposed heat flux causes an increase in the $h_r$, value at the low quality. Finally, at a higer refrigerant saturation temperature the $h_r$, value is found to be lower.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.3 s.108
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• pp.240-246
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• 2006

In the air-conditioner, refrigerant induced noise and vibration can be increased when the airflow rate is reduced in order to decrease the noise at the low mode. Through the test and analysis of this kind of noise, it can be verified that the main reasons of refrigerant induced noise are the velocity and flow Induced force of the refrigerant at the inlet of the evaporator, So, in order to reduce this velocity, quality at the evaporator inlet should be minimized. And, in order to reduce flow induced force of the refrigerant, sudden change of fluid flow must not be occurred. So, in this paper, we will review the characteristics of refrigerant cycle and find how the quality and flow induced force can be minimized.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.9
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• pp.855-862
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• 2004

This study reports pressure drops during evaporation for R-l34a, R-407C (a mixture of 23 wt% R-32, 25 wt% R-125, and 52 wt% R-l34A) and R-410A (a mixture of 50 wt% R-32 and 50 wt% R-125) in the oblong shell and Plate heat exchanger. The effects of the mass fluxes, heat fluxes, refrigerant saturation temperatures and vapor quality of refrigerants on the measured data were explored in detail. The present data showed that pressure drops of all refrigerants increase with the vapor quality. At a higher mass flux, pressure drops are higher for the entire range of the vapor quality A rise in the heat flux doesn't show significant effects on the pressure drops. Finally, at a higher saturation temperature the pressure drops are found to be lower. The pressure drops for R-407C were approximately 20% lower than those of R-l34a. R-410A had 33% lower pressure drops than R-l34a. Correlation is also provided for the measured pressure drops in terms of the friction factor.

• Fire Science and Engineering
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• v.34 no.2
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• pp.49-53
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• 2020

This study aimed to identify the characteristics of 40 chemical accidents that occurred in Jeollabuk-do from 2004 to 2019. During this time, there were 2.5 accidents per year on average in the province; their types were classified as spill/leak, fire, explosion, adverse reaction, and complex. There were 34 leaks and six explosions, and they are categorized as follows: 12 by worker error, 16 from facility defects, and 12 by transport vehicle accidents. The substances involved in these accidents were ammonia (15%), sulfuric acid (12.5%), and silicon tetrachloride (7.5%). Notably, the rate of chemical accidents (75%) is the highest during spring and summer. In order to reduce chemical accidents, first, there should be compliance with the relevant laws. Second, the quality of safety education and training of workers should be improved. Finally, valuable government support is also necessary to improve facilities.