• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.3
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• pp.59-70
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• 2020

Obtaining external forced convection heat transfer from bubble boiling and validating it with experimental results using cryogenic liquids are suggested to derive total heat transfer coefficient with pool boiling condition in the case of coil type heat exchanger with a bundle of tubes and to overcome the limitation of using the empirical correlation. Experiment is conducted with pool boiling heat transfer of saturate liquid nitrogen with helical coil type heat exchanger using liquid oxygen as hot stream fluid. Experimentally measured heat transfer coefficient is well-agreed with the estimated curve considering nucleate boiling and forced convection induced by bubble rise.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.465-474
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• 2014

To validate the accuracy of the boiling heat flux partitioning model, an experiment was performed to investigate how the wall heat flux is divided into the three heat transfer modes of evaporation, quenching, and single-phase convection during subcooled nucleate boiling on a vertical wall. For the experimental partitioning of the wall heat flux, the wall heat flux and liquid-vapor distributions were simultaneously obtained using synchronized infrared thermometry and the total reflection technique. Boiling experiments of water with subcooling of $10^{\circ}C$ were conducted under atmospheric pressure, and the results obtained at the wall superheat of $12^{\circ}C$ and average heat flux of $283kW/m^2$were analyzed. There was a large difference in the heat flux partitioning results between the experiment and correlation, and the bubble departure diameter and bubble influence factor, which account for a portion of the surrounding superheated liquid layer detached by the departure of a bubble, were found to be important fundamental boiling parameters.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.5
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• pp.587-593
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• 2009

This study was carried out to investigate the quality characteristics of ginseng Jung Kwa and Jung Kwa solution prepared according to boiling frequency on Jung Kwa process. Ginseng Jung Kwa was made as follows: washed ginseng 8 kg was boiled 5 min with water 16 kg and then boiling water 8 kg was removed. Sucrose 10 kg was added to boiled ginseng soaking in hot water. Jung Kwa was boiled down for 60 min in sugar syrup and soaked for 24 hrs. According to the above process, Jung Kwa was boiled down 5 times. Moisture and pH of Jung Kwa and Jung Kwa solution decreased as the number of boiling time increased and $^{\circ}Brix$ of Jung Kwa solution increased. Crude saponin content of last Jung Kwa (GJ 6) increased to 4 times of raw ginseng. Content of Rf and Rd, component of ginsenosides, increased 77 and 16 times on Jung Kwa, respectively and content of crude saponin on last Jung Kwa solution (GJS 5) was 61.88 mg/g. The other ginsenosides on Jung Kwa decreased. As the number of boiling time increased, concentration of total sugar, glucose and fructose of Jung Kwa and Jung Kwa solution increased. Content of total organic acid on Jung Kwa decreased, especially, succinic acid, main organic acid of ginseng, decreased rapidly. L value of Jung Kwa decreased whereas a and b values increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.3 no.1
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• pp.35-41
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• 1974

The experiment attempted to detect the loss of mineral substances in the crude herb, especially for the Platycodon graucum Nakai after removal of its acrid flavor. The results obtained are summarized as follows: 1. The quantity of the mineral substance was K Ca P Mg and Na in orders. The above substances were more prevalent in the part of the plant above the ground than the plant below the ground, however Na remained the same in both parts of the plant. 2. As a result of water immersion, in order to clear away the acrid flavor, the one day exudate showed that K was highest in amount and in the others there was no significant difference. There was a slight increase, however, in the amount of Ca K Mg P and Na because of exudation on the 3rd and 5 th days. 3. The amount of the exudate was increased by boiling rather than simple water immersion, but the amount of Ca was decreased.

• The Korean Journal of Community Living Science
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• v.25 no.2
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• pp.261-269
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• 2014

This study evaluates the nutritional retention factors influencing beef based on different cuts and boiling. Two cuts (brisket and shin foreshank) were prepared from beef and used in this experiment. Boiling methods were applied to each cut. The fat content of the boiled shin foreshank cut (236.43%) exceeded that of the brisket cut (142.38%). The moisture content of the boiled brisket cut (47.68%) was lower than that of the shin foreshank cut (49.54%). The sodium content of the boiled shin foreshank cut (47.89%) exceeded that of the brisket cut (37.30%). The potassium content of the boiled brisket cut (41.90%) exceeded that of the shin foreshank cut (39.63%). The calcium content of the boiled brisket cut (48.43%) was lower than that off the shin foreshank cut (71.34%). The phosphorus content of the boiled brisket cut (58.09%) exceeded that of the shin foreshank cut (57.24%). The iron content of the boiled brisket cut (72.72%) was lower than that of the shin foreshank cut (87.29%). Nutritional retention factors represent output data on cooking methods with a yield (%) for each item.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.12 s.255
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• pp.1236-1242
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• 2006

The local heat flux of spray cooling in the film boiling region were experimentally investigated for the spray region of $D_{max}$ = $0.005{\sim}0.03m^3/(m^2s)$. A twin-fluid full cone spray nozzle was employed for the experiment and the distributions of droplet flow rates were obtained for air-water full cone sprays. A stainless steel block was cooled down from initial temperature of about $800^{\circ}C$ by full cone spray. In the region near the stagnation point, it was found that the experimental data are in good agreement with the results predicted from the correlations between the local heat transfer and the local droplet flow rate proposed in the previous report. However, it was found that the experimental data of $D_r$ > $0.01m^3/(m^2s)$ are a little smaller than the results predicted from the correlations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1133-1140
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• 2009

The purpose of this study is to determine the most efficient method of removing sulfur dioxide from traditional herbal medicine (hanyak) by slow boiling using a traditional pipkin and an electronic slow boiler. By boiling a hanyak batch containing] 56.4ppm of sulfur dioxide for one hour using a traditional pipkin, 96.7 percent of the sulfur dioxide was removed, while two hours of slow boiling removed ]00 percent. Among different cover materials placed over the pipkin during the slow boiling process including the traditional Korean paper (hanji), regular hanji, filter paper and regular paper, the traditional hanji produced the best performance of sulfur dioxide removal. The initial pH level of the traditional hanji was] 0.03. After one hour of slow boiling hanyak batches in a traditional pipkin covered with traditional hanji, where each batch contained sulfur dioxide of 48ppm, 193ppm, 753ppm and 1,506ppm respectively, the pH level of the hanji cover material was reduced to 9.37, 9.14, 8.9 and 8.03 in respective cases. Our experiment using an electronic medicine slow boiler showed 82.8 percent removal of sulfur dioxide after one hour of slow boiling a hanyak batch containing 753ppm of sulfur dioxide. When hanyak batches were boiled by placing traditional hanji, filter paper, active carbon and hardwood charcoal separately in the middle area within the electronic slow boiler, the sulfur dioxide removal rate was 73.6 percent, 72.8 percent, 73.9 percent and 69.5 percent, respectively. When charcoal was added so as to remove toxic materials from the hanyak, its presence impeded the sulfur dioxide flow and thus reduced the removal efficiency contrary to our anticipation.

• Korean Journal of Medicinal Crop Science
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• v.3 no.3
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• pp.226-232
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• 1995

Extraction methods and instrumental analytical conditions were compared to establish a fast and appropriate analytical method to determine saikosaponins in Bupleurum falcatum. Using HPLC, analysis of diene-saikosaponin treated with 2% acid was faster than that of saikosaponin itself. Among various extraction methods, extraction by standing in methanol at room temperature showed highest efficieny, and extraction with boiling methanol was shorter in analytical time and showed good chromatogram. And we could analyze many samples faster using HPTLC but the analytical accuracy was low. In extraction and analysis of saikosaponins, extraction with boiling methanol and acidic treatment was fast and easy analytical method. And for selecting useful lines in component breeding, we think TLC method was better.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.119-124
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• 2001

This experimental study was conducted to figure out the characteristics of convective heat transfer non boiling vertical downward flow with polymer additives. This experiment was studied in diameter, 800mm heating length and $1{\times}10^5 W/m^2$ heat flux. The polymer concentration ranged 0ppm to 500ppm with corresponding from superficial liquid velocity 1.25m/s to 2.5m/s in non bo vertical up and downward flow. Experimental results show that the characteristics of convective transfer was a strong function of polymer concentration and it has decreased with increasing polymer concentration in non boiling up and vertical downward flow.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.337-342
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• 1996

The pool-boiling critical heat flux (CHF) of water on small flat plates has been experimentally investigated focusing on the effects of the inclination angle and size of the heated surface under near atmospheric pressure. The second-phase experiment was accomplished to find out the general CHF behavior for over-all inclination angles from -90$^{\circ}$ to 90$^{\circ}$using two plate-type test sections (30$\times$150 mm and 40$\times$150 mm) submerged in a slightly subcooled water pool. Test results generally confirm the first-phase findings and show little effect of inclination angle for inclined upward-facing cases. CHF position moves to lower position with the increase of the heater characteristic size and inclination angle(from -30$^{\circ}$to 60$^{\circ}$).