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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
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Journal DOI :
Korean Society of Marine Engineers
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Volume & Issues
Volume 40, Issue 6 - Jul 2016
Volume 40, Issue 5 - Jun 2016
Volume 40, Issue 4 - May 2016
Volume 40, Issue 3 - Mar 2016
Volume 40, Issue 2 - Feb 2016
Volume 40, Issue 1 - Jan 2016
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Numerical analysis of solar pond with insulation layer
Yu, Jik-Su ; Mun, Soo-Beom ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 264~269
DOI : 10.5916/jkosme.2016.40.4.264
This paper reports a fundamental study of temperature characteristics of a solar pond with an insulation layer. Further, these characteristics were compared with those of a solar pond without the insulation layer. The governing equation was discretized via finite difference method. The governing equations are two-dimensional unsteady-state second-order partial differential equations. The conclusions of the study are as follows: 1) If the depth of the solar pond was increased, the desired effect of increase in temperature was not produced because the amount of solar insolation received by the bottom of the solar pond decreased. 2) As the temperature of the soil during winter is higher than the temperature of the water in a solar pond, heat was transferred from the soil to the solar pond. 3) For the case of the solar pond with insulation layer, it was estimated that the dependence rate of solar energy was 83.3% and that of the boiler was 16.7%.
Enhanced heat transfer in the convergent rectangular channels with ∧/∨-shaped ribs on one wall
Lee, Myung-Sung ; Yu, Ji-Ui ; Jeong, Hee-Jae ; Choi, Dong-Geun ; Ha, Dong-Jun ; Go, Jin-Su ; Ahn, Soo-Whan ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 270~274
DOI : 10.5916/jkosme.2016.40.4.270
The effect of the rib angle-of-attack on heat transfer in the convergent channel with
-shaped ribs was examined experimentally. Four differently angled ribs (a =
) were placed to only the one sided wall. The ribbed wall was manufactured with a fixed rib height (e) of 10 mm and rib spacing (p)-to-height (e) ratio of 10. The convergent channel had a length of 1,000 mm and a cross-sectional areas of
at inlet and
at exit. The measurement was conducted for the Reynolds numbers ranging from 22,000 to 75,000. The results show that the Nusselt number is generally higher at higher Reynolds number and that an angle-of-attack of
-shaped rib produces the greatest Nusselt number.
CFD validation for subcooled boiling under low pressure
Choi, Yong-Seok ; Kim, You-Taek ; Lim, Tae-Woo ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 275~281
DOI : 10.5916/jkosme.2016.40.4.275
Subcooled boiling under low pressure was numerically investigated using computational fluid dynamics(CFD). The wall boiling model was used for simulating the subcooled boiling; this model requires sub-models consisting of bubble departure diameter, nucleation site density and bubble departure frequency. The CFD code CFX provides the default models based on experimental data. Because these models are mostly developed under high pressure conditions, it would not be predicted well in low pressure conditions. Thus in this study, CFD validation for subcooled boiling under low pressure was analyzed. The numerical results were compared with experimental data from published paper. Simulations were performed with mass flux ranging from 250 to
, heat flux ranging from 0.37 to
and constant outlet pressure of 0.11 MPa. Employing the empirical correlation developed under low pressures could increase the accuracy of numerical analysis.
Performance analysis of a cooling system with refrigerant in a marine absorption refrigerator
Yun, Sang-Kook ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 282~287
DOI : 10.5916/jkosme.2016.40.4.282
Recently in order to protect the ocean environment and to reduce energy consumption, shipbuilders have been developing highly economized ships. This research analyzed the possibility of adopting the onshore absorption refrigerator to offshore ships having a cooling system with refrigerant by using the waiste heat of the engine jacket cooling water instead of compression refrigerators. The results showed that R236fa could be a suitable medium for absorbing the heat of the absorber and condenser in an absorption refrigerator. The cooling system using R236fa achieved a high COP of 0.798, which is 15% and 5% higher than an air cooling system with a cooling tower and a water cooling system with a heat exchanger, respectively. The cooling system with R236fa achieved high efficiency with a 25% reduction in flow rate of LiBr solution and only 15.7% flow rate of cooling medium as compared to the water cooling system. The heating of sea water by the engine jacket water flowing out from the generator can prevent the crystallization of LiBr solution due to the low temperature of sea water.
A study on the analysis of bearing reaction forces and hull deflections affecting shaft alignment using strain gauges for a 50,000 DWT oil/chemical tanker
Lee, Jae-Ung ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 288~294
DOI : 10.5916/jkosme.2016.40.4.288
In modern ships, the shafting system often becomes stiff owing to the high engine power, whereas the hull structure becomes more flexible owing to optimization using high-tensile-strength thick steel plates; therefore, more sophisticated shaft alignments are required. In this study, strain gauge-based measurement was conducted under five vessel operating conditions and bearing reaction forces and hull deflections affecting shaft alignment were analyzed for a 50,000 dead weight tonnage oil/chemical tanker that has gained repute as an eco-friendly vessel in recent years. Furthermore, the analytical results from each technique-theoretical calculation, jacking ups, and strain gauges-were cross-checked against each other in order to enhance the degree of accuracy and reliability of the calculation.
A numerical analysis of the delivery pressure wave in a 210-kW/cyl fuel injection pump for medium-speed diesel engines
Kong, Kyeong-Ju ; Jung, Suk-Ho ; Lee, Sang-Deuk ; Koh, Dae-Kwon ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 295~300
DOI : 10.5916/jkosme.2016.40.4.295
This paper presents a numerical analysis of the delivery pressure wave in a 210-kW/cyl fuel injection pump (P. Corporation, Changwon-si, Korea) for medium-speed diesel engines using Ansys Fluent R15.0. Results obtained from experiment and from numerical analysis of the fuel delivery pressure wave were compared and found to be similar, thereby confirming the reliability of the numerical analysis of the delivery pressure wave in the fuel injection pump.
Theoretical and experimental analysis of the lateral vibration of shafting system using strain gauges in 50,000-DWT oil/chemical tankers
Lee, Jae-Ung ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 301~306
DOI : 10.5916/jkosme.2016.40.4.301
During the initial stage of propulsion shaft design, the shaft alignment process includes a thorough consideration of lateral vibration to verify the operational safety of the shaft. However, a theoretical method for analyzing forced lateral vibrations has not been clearly established. The methods currently used in classification societies and international standards can only ensure a sufficient margin to avoid the blade-passing frequency resonance speed outside the range of
of the maximum continuous rating (MCR) for the engine. Typically, in shaft alignment analyses, longer center distances between the support bearings promote affirmative results, but the blade order resonance speed can approach the lower limit for lateral vibration. Therefore, this matter requires careful attention by engineers, and a verification of the theoretical analysis by experimental measurements is highly desirable. In this study, both theoretical and experimental analyses were conducted using strain gauges under two draught conditions of vessels used as 50,000-DWT oil/chemical tankers, introduced recently as eco-friendly ships. Based on the analyses, the influence of the lateral vibration on the shafting system and the system's reliability was reviewed.
A study of feasibility of using compressed wood for LNG cargo containment system
Kim, Jong-Hwan ; Ryu, Dong-Man ; Park, Seong-Bo ; Noh, Byeong-Jae ; Lee, Jae-Myung ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 307~313
DOI : 10.5916/jkosme.2016.40.4.307
When liquefied natural gas (LNG) is stored in a tank, it is necessary to maintain low temperature. It is very important that insulation techniques are applied to the LNG cargo because of this extreme environment. Hence, laminated wood, especially plywood, is widely used as the structural member and insulation material in LNG cargo containment systems (CCS). However, fracture of plywood has been reported recently, owing to sloshing effect. Therefore, it is necessary to increase the strength of the structural member for solving the problem. In this study, compressed wood, which is used as a support in LNG independent type B tanks, was considered as a substitute for plywood. Compression and bending tests were performed on compressed wood under ambient and cryogenic temperatures to estimate the mechanical behaviors and fracture characteristics. In addition, the direction normal to the laminates surface was considered as an experimental variable. Finally, the feasibility of using compressed wood for an LNG CCS was evaluated from the test results.
A forging die design to improve the flower shape of flange bolt
Kim, Kwan-Woo ; Lee, Geun-Tae ; Cho, Hae-Young ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 314~319
DOI : 10.5916/jkosme.2016.40.4.314
Flange bolt has a circular flange under the head that acts like a washer to distribute the clamping load over a large area. Flange bolt has usually been manufactured by cold forging. Flower shape defect occurs in the flange forging stage. This defect causes lack of dimensional accuracy and low quality. So it is needed to improve these forging defects. In this study, die design method for flower shape defect of flange bolt was suggested. In order to improve flower shape defect, inner diameter of the addition die in conventional forging process was modified. The forging process with applied modified die was simulated by commercial FEM code DEFORM-3D. The simulated results for modified die were confirmed by experimental trials with the same condition.
Design of eccentric forging process for camber bolts using finite element method
Kim, Kwan-Woo ; Qiu, Yuan-Gen ; Cho, Hae-Yong ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 320~324
DOI : 10.5916/jkosme.2016.40.4.320
A new eccentric forging process for camber bolts has been suggested in this study. The camber bolt is manufactured by a two-step process: the typical forging process for normal bolts and the trimming process for the eccentric flange. The processes are performed under high forging load and generate a large amount of chip during trimming. A new forging process has been required in order to overcome these problems. The eccentric forging is the new process in which the load axis is offset from the central axis, as against central load applied in a typical forging process. The eccentric forging process could reduce forging load and save the amount of chip. In order to manufacture camber bolts by an optimum process, it is required to adjust the geometry of eccentric die and the offset from the central axis.
A study on fabrication of HNS remote sensor module with printed ITO films
Lee, Seok-Hwan ; Cho, Sung-Min ; Kim, Chang-Min ; Kim, Hyeong-Ho ; Yang, Han-Uk ; Oh, Ji-Eun ; Chang, Ji-Ho ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 325~329
DOI : 10.5916/jkosme.2016.40.4.325
In this study, we investigated the feasibility of using printed Indium Tin Oxide (ITO) film as a remote sensor for Hazardous and Noxious Substances (HNS). To improve the quality of the ITO films, binder mixing ratio, Sn concentration in ITO, thermal treatment temperature, and printing process conditions were optimized. We fabricated an electrical resistance-type liquid sensor, and to confirm the sensor operation, the change in resistance in air and seawater was monitored. The change in resistance of the ITO sensor was explained in terms of reduction reaction on the surface. Further, the sensor was controlled by Arduino, and the remote data acquisition was demonstrated.
CFD and experiment validation on aerodynamic power output of small VAWT with low tip speed ratio
Heo, Young-Gun ; Choi, Kyoung-Ho ; Kim, Kyung-Chun ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 330~335
DOI : 10.5916/jkosme.2016.40.4.330
In this study, aerodynamic characteristics of the blades of a helical-type vertical axis wind turbine(VAWT) have been investigated. For this purpose, a 100-W helical-type vertical axis wind turbine was designed using a design formulae, and a 3D computational fluid dynamics analysis was performed considering wind tunnel test conditions. Through the results of the analysis, the aerodynamic power output and flow characteristics of a helical blade were confirmed. In order to validate the aerodynamic power output obtained through the analysis, a wind tunnel test was performed by using a full-scale helical-type vertical axis wind turbine. The 3D analysis technique was validated by comparing its results with those obtained from the wind tunnel test.
Performance analysis of legacy line communication using high current powerlines in midrange wind turbines
Kim, Kyoung-Hwa ; Jeong, Seong-Uk ; Nam, Seung-Yun ; Kim, Hyun-Sik ; Sohn, Kyung-Rak ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 336~341
DOI : 10.5916/jkosme.2016.40.4.336
This paper presents an implementation of a communication network in wind turbines, which exploits the power-line communication system (PLC). We used an inductive coupling unit and a multi-interface device to connect a data-communication terminal to the power line, to ensure that stable communication was possible at various electric current and voltage values of the generator. The results of the operation tests conducted on an operational wind turbine showed that the implemented PLC demonstrated a transmission rate of at least 43 Mbps with a 100% success rate. Moreover, a real-time image was transmitted. Thus, the system could be a useful alternative for implementing a communication network in wind turbines that does not require additional channels. Since the presented system is easy to implement, and can support various interfaces for data communication, it will be quite useful when a real-time monitoring system is launched in wind turbines.
Economic analysis on the applications of shipboard LED luminaires
Park, Seo-Jun ; Byeon, Sung-Hwan ; Kim, Sun-Jae ; Park, Kyoung-Soo ; Kil, Gyung-Suk ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 342~347
DOI : 10.5916/jkosme.2016.40.4.342
This paper dealt with the economic analysis on the application of shipboard LED (Light Emitting Diode) luminaires to replace incandescent and fluorescent lamps, which account for over 80 % of light source on a training or naval vessel. The rates of savings achieved in the power consumption, initial investment, maintenance cost, and fuel cost were analyzed. The break-even points and the
emissions were also calculated. For the training vessel, the initial investment was increased by 3.8 times, while the maintenance cost over five years was reduced by 51 %. When 40 %, 50 %, and 60 % of luminaires were turned on, the calculated break-even points were 11 months, 9 months, and 7 months, respectively. On the other hand, the initial investment was increased by 3.5 times while the maintenance cost over five years was saved by 55 % for the naval vessel. The break-even points were calculated as 15 months, 12 months, and 10 months, respectively. Moreover, the
emissions of the training and the naval vessels were reduced by 69 % and 65 %, respectively. From the results, it was revealed that the maintenance cost can be reduced by more than 50 %, and that the power consumption, fuel cost, and
emissions can be reduced by more than 60 % if LED luminaires are used on two types of vessels.
Variable speed operation of SRM with dual rating using proper voltage excitation
An, Young-Joo ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 348~352
DOI : 10.5916/jkosme.2016.40.4.348
This paper addresses the efficient improvement of the Switched Reluctance Motor(SRM) by the proper voltage excitation. In the case of loads with large operational motor-speed differences such as washing machine, an SRM system driven by a constant DC-link voltage is not useful for improving the efficiency. To reduce the effect of the excess DC-link voltage, AC-DC control converter that uses a silicon controlled rectifier instead of diode rectifier is employed in the SRM driver system. AC-DC control converter supplies a proper link voltage for low-speed operation. The experimental results demonstrated that the efficiency of the system was improved at low speeds.
High-frequency characteristics of short-wavelength transmission line on polyether sulfone thin film for a realization of transparent flexible wireless communication device
Yun, Young ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 353~361
DOI : 10.5916/jkosme.2016.40.4.353
This work presents an investigation of the radio frequency characteristics of an FTLPGS (fishbone-type transmission line employing periodic ground structure) fabricated on PES (polyether sulfone) for the realization of a transparent flexible wireless communication device. According to the results, the FTLPGS on PES showed a shorter wavelength characteristic when compared with a conventional coplanar waveguide. Concretely, the wavelength of the FTLPGS was 1.91 mm at 50 GHz, which was 48.5% of the conventional coplanar waveguide. The bandwidth extraction result showed that the passband of the FTLPGS on PES was 250 GHz. Unlike conventional periodic structures, the characteristic impedance of the FTLPGS on PES also showed a very low frequency dependency. A miniaturization of the RF circuit on the PES substrate was made possible by the FTLPGS on PES having shown characteristic impedance lower than that of conventional transmission lines. These results mean that, with a broadband operation frequency, the FTLPGS on PES is a suitable construction application for the transmission line and distributed passive components.
Basic study of residual marine fuels quality
Park, Hee-Woo ; Chun, Kang-Woo ; Kim, Jin-Hee ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 362~368
DOI : 10.5916/jkosme.2016.40.4.362
In the recent International Maritime Organization's (IMOs) Maritime Safety Committee's 93rd session, the International Chamber of Shipping and International Parcel Tankers Association addressed marine fuel oil quality problems: increasing diluents in marine fuel oil, ignition in engine rooms due to the low flash point of fuel oil, and marine fuel oils that can damage marine engines. To deal with these marine fuel oil quality problems, the International Maritime Organization secretariat appointed the worlds marine fuel oil monitoring institute and constituted a correspondence group to determine the fuel oil quality required by MARPOL Annex VI regulation 14.8 (sulfur content less than 0.5%). In this study, basic research that can help with responding to marine fuel quality issues and the IMO's work is conducted. In order to perform this basic research, the off-spec ratio related to the fuel oil quality standard (ISO 8217:2012), density distribution tendency, gross specific energy, and correlation between components in the fuel oil are analyzed through actual marine fuel oil (residual marine fuel) data from the Port of Singapore.
Nonproportional viscous damping matrix identification using frequency response functions
Min, Cheon-Hong ; Kim, Hyung-Woo ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 4, 2016, Pages 369~373
DOI : 10.5916/jkosme.2016.40.4.369
Accurate identification of damping matrix in structures is very important for predicting vibration responses and estimating parameters or other characteristics affected by energy dissipation. In this paper, damping matrix identification method that use normal frequency response functions, which were estimated from complex frequency response functions, is proposed. The complex frequency response functions were obtained from the experimental data of the structure. The nonproportional damping matrix was identified through the proposed method. Two numerical examples (lumped-mass model and cantilever beam model) were considered to verify the performance of the proposed method. As a result, the damping matrix of the nonproportional system was accurately identified.