• Journal of computational fluids engineering
• /
• v.19 no.4
• /
• pp.86-93
• /
• 2014

Increased demand of power-transformer's capacity inevitably results in an excessive temperature rise of transformer components, which in turn requires improved radiator design. In this paper, numerical simulation of the cooling performance of an ONAN-type (Oil Natural Air Natural) radiator surrounded by air was performed by using CFX. The natural convection of the air was treated with the full-model. The present parametric study considers variation of important variables that are expected to affect the cooling performance. We changed the pattern and cross-sectional area of flow passages, the fin interval, the flow rate of oil and shape of flow passages. Results show that the area of flow passage, the fin interval, the flow rate of oil and shape of flow passages considerably affect the cooling performance whereas the pattern of flow passages is not so much influential. We also found that for the case of the fin interval smaller than the basic design, the temperature drop decreases while a larger interval gives almost unchanged temperature drop, indicating that the basic design is optimal. Further, as the flow rate of oil increases, the temperature drop slowly decreases as expected. On the other hand, when the shape of flow passages are changed, temperature drop is increased, indicating that the cooling performance is enhanced thereupon.

• Korean Journal of Food Science and Technology
• /
• v.29 no.2
• /
• pp.261-265
• /
• 1997

To know the availability of double fractionated palm olein (DFPL) for vegetable oil in commercial mayonnaise preparation, oxidative stability and stability to cold test of DFPL, soybean oil and blended oils (blended soybean oil with DFPL) were tested. Mayonnaises with these oils were prepared and then emulsion stability at low temperature $(-5^{\circ}C)$ were compared. The oxidative stability of vegetable oil by Rancimat test showed that induction time of DFPL (26.9 hr) was longer when compared with soybean oil (13.4 hr), and became longer with increase of DFPL ratio in the blended oil. Emulsion stability of mayonnaises at low temperature $(-5^{\circ}C)$ was decreased with the increase of DFPL ratio in the blended oil. But, mayonnaise with blended oil of below 20% DFPL was comparable to that with soybean oil only. Among quality characteristics of mayonnaises with soybean oil and blended oil (soybean oil 85% plus DFPL 15%) the latter showed stronger oxidative stability and less flavor reversion during high temperature treatment. This result suggested that the possibility of DFPL to substitute for vegetable oil in the preparation of commercial mayonnaise.

• Journal of Navigation and Port Research
• /
• v.46 no.4
• /
• pp.297-302
• /
• 2022

An exothermic oil absorbent sheet with calcium chloride crystals can be fabricated, by dipping a clean polypropylene fabric in calcium carbonate and hydrochloric acid solution and drying it. The exothermic oil absorbent sheet applied to the seawater surface, releases heat by the dissociation of calcium chloride. The dissociation heat liquefies the solidified low-sulfur fuel oil at a low temperature, and converts it to a state at which it can be absorbed. The optimum mole concentrations of calcium carbonate and hydrochloric acid required for the exothermic oil absorbent sheet, are 0.25 M and 0.5 M, respectively. The oil absorption capacity of the exothermic oil absorbent sheet for low sulfur fuel oil depends on the seawater temperature. But, it is highly excellent at 4.5-7.08 g/g at 10℃, the average seawater temperature during the winter in Korea. The exothermic oil absorbent sheet is an excellent alternative in absorbing low-sulfur fuel oil in winter and removing it from seawater.

• KSTLE International Journal
• /
• v.3 no.1
• /
• pp.26-29
• /
• 2002

The International Lubricant Standardization and Approval Committee (ILSAC) GF-3 passenger car engine oil specification has been introduced commercially in July 2001. The new specification oil provides superior performance in terms of fuel economy, control of high temperature deposits, and oil consumption. These enhanced performances of GF-3 engine oil need high quality base oil as well as a better additive system. In this paper, the effect of base oil on various performances of ILSAC GF-3 engine oil was investigated. From the GF-3 sequence engine tests, Group III base oil shows better performance in fuel economy retention, oxidation and varnish control than combination of group III and group II or group III and group 1.

• Tribology and Lubricants
• /
• v.24 no.2
• /
• pp.82-89
• /
• 2008

The purpose of this study is to develop the proto type sensor installed inside an oil filter in order to detect oil deterioration level. The sensor is made up with two concentric cylinders with constant gap in between and a filter element inside the central area. The size will be designed as similar as real oil filters. The sensor will be tested on a test rig, which is circulating engine oil, with the same size of an oil filter adapting housing as real engines'. It will be measured the capacitance of a sample engine oil, then be able to be gotten the dielectric constant. The changes in the dielectric constant could be correlated with the engine oil deterioration level if the sensor development would be completed. In this paper, it will be shown the test results carrying out under variable temperature conditions at atmosphere pressure.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1999.11a
• /
• pp.184-189
• /
• 1999

This Paper presents the friction and lubrication charateristic related with oil aeration. It is well known that oil aeration occurs severe problem on lubrication system, in particular, in the engine bearings and hydraulic lash adjuster. In this study, engine tests were carried out in motoring conditions. In order to investigate oil aeration characteristics, we measured oil aeration with respect to oil temperature, oil viscosity, modified oil drain system. From the results, we concluded that aeration can be reduced by improving oil drain system and FMEP can be reduced by minimising of aeration.

• Journal of Hydrogen and New Energy
• /
• v.33 no.1
• /
• pp.77-84
• /
• 2022

The experimental work has been carried out for the study of pyrolysis of oil samples used in industrial and utility boilers in Korea. For five oil samples, the characteristics of pyrolysis have been investigated with a thermogravimetric analyzer (TGA), and their kinetic parameters were obtained and compared each other. The rate order of pyrolysis rate for five oils were as follows: by-product fuel oil, pyrolysis oil, diesel, a heavy oil and refined oil. The pyrolysis of refined oil has been successfully described by the three step, first order reaction model while the single step reaction model has been used for other oils. For the reaction temperature over 550 K, the reactivity of refined oil was very poor compared with other oils.

• Tribology and Lubricants
• /
• v.24 no.4
• /
• pp.170-178
• /
• 2008

In this paper, it is described how the problems appeared at the previous proto type sensor are improved. As changing the pressure and temperature of engine oil in a test rig, the modified sensor is tested. Then, the measured results of capacitance and the corresponding dielectric constants under various temperatures and pressures are shown. It turns out that the electrical signal gotten from the electrodes of newly developed sensor can be more stable under the various operating conditions.

• Resources Recycling
• /
• v.4 no.4
• /
• pp.12-15
• /
• 1995

In this paper, some representative waste tire pyrolysis were investigated together with the analysis of the problems associated with the commercialization of various waste tire treatment technologies. Also, R & D results on recovering the oil from the pyrolysis of waste tires, when waste oil was used as a heating medium, were summarized in this study. Experimental results show that the present pyrolysis process has both lower pyrolytic temperature and higher pyrolysis rate than usual one and that the quality of the product oil and residue obtained was relatively even with large availability.

• Tribology and Lubricants
• /
• v.11 no.1
• /
• pp.12-19
• /
• 1995

A finite element approach to analyzing the film pressure of engine bearings has been presented based on the viscosity-temperature equations. The calculated results from each viscosity model are compared with each other for various temperature models of the oil film. The FEM results show that the appropriate selection of the viscosity-temperature model is very important factor for analyzing the film pressure distribution of engine bearings.