• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.1
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• pp.57-62
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• 2015

The wet brakes used on a forklift often produce noise upon engagement. The elimination or reduction of this squeal noise is an important task for the improvement of the comfort of those operating these machines. In this paper, a test rig was developed for the testing of brake noise, and the squeal noise was measured with this apparatus. Automatic transmission fluid and grooves in the material of the friction-plate pad were found to be the main factors causing squeal noise. In order to identify the characteristics of this type of noise, signal analyses of the noise were conducted using different frequency spectra. The experimental results showed that the viscosity of the automatic transmission fluid and the groove pattern on the friction-plate pad largely affected the reduction of the wet brake squeal noise made by an industrial forklift.

• Journal of Ocean Engineering and Technology
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• v.27 no.1
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• pp.9-15
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• 2013

This paper calculates the mating dynamic forces of a semi-submersible offshore structure's topside module, where a hull moored in the sea is combined with a topside module carried by a heavy lift vessel, as a mating installation method. The environmental conditions include various wave directions and wave heights, with constant wind and current speeds. Appropriate ballast and de-ballast plans for the heavy lift vessel and hull of the semi-rig should be performed in order to safely obtain these forces, whereas a fixed platform or the GBS (Gravity based structure) type of offshore structure only needs a ballast plan for the heavy lift vessel. From this paper, the allowable wave height or wave direction for the mating procedure can be investigated based on the standard DAF (Dynamic amplitude factor) of the rules and regulations.

• The KSFM Journal of Fluid Machinery
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• v.6 no.2 s.19
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• pp.7-14
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• 2003

This paper describes reliability characteristics of an air foil journal bearing for high-speed turbomachinery at a room temperature. To verify the reliability of air foil journal bearing, lift-off characteristics, load carrying capacity, and 10,000 cycle start-stop test were performed with a motor-driven test rig. A lift-off test shows the relationship between the rotating speed of the shaft and the frictional torque with bearing surface. About a load-carrying capacity, the tested air foil journal bearing produced a load capacity of 500N at an operating speed of 15,000rpm, which is compared with results of numerical analysis and empirical coefficients. Finally, the trends in change of start torque, stop torque, and bearing temperature were shown during a 10,000-cycle start-stop test of an air foil journal bearing. We found that an air foil bearing performs well, as a supported bearing for the high-speed turbocompressor.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.1
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• pp.59-65
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• 2004

The configuration of intake port and piston is a dominant factor of inlet air flow and mixture formation in an engine cylinder, resepectively. This study has analyzed intake port and piston characteristics for swirl flow of a heavy-duty LPG engine. As an available technology to optimize intake port, the steady flow rig test has been applied for measuring swirl ratio and mean flow coefficient. And we measured the mean velocity and turbulence intensity of swirl flow under motoring condition in transparent engine cylinder by backward scattering LDV system. From these results, the piston and cylinder head with a good evaluated swirl flow characteristics were developed and adapted fur a 11L heavy-duty engine using the liquid phase LPG injection (LPLI) system. The obtained results are expected to be a fundamental data for developing intake port and piston.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.2
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• pp.195-201
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• 2014

Flexible risers have been used extensively in recent years for floating and early production systems. Such risers offer the advantage of having inherent heave compliance in their catenary thereby greatly reducing the complexity of the riser-to-rig and riser-to subsea interfaces. Another advantage with flexible risers is their greater reliability. Concerns about fatigue life, gas permeation and pigging of lines have been overcome by extensive experience with these risers in production applications. In this paper, flexible riser analysis results were compared through coupled and uncoupled dynamic analyses methods. A time domain coupled analysis capability has been developed to model the dynamic responses of an integrated floating system incorporating the interactions between vessel, moorings and risers in a marine environment. For this study, SPM (Single Point Mooring) system for an FSU in shallow water was considered. This optimization model was integrated with a time-domain global motion analysis to assess both stability and design constraints of the flexible riser system.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.7
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• pp.935-941
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• 2012

This paper describes a study of conventional electrical rig and simulated application of Flywheel Energy Storage system on the power system of the offshore plants with dynamic positioning system with the following aims: improve fuel consumption on engines, prevent blackout and mitigate voltage sags due to pulsed load and fault. Fuel consumption has been analyzed for the generators of the typical drilling rigs compared with the power plant with Flywheel Storage Unit which has an important aid in avoiding power interruption during DP (Dynamic Positioning) operation. The FES (Fly wheel Energy storage System) releases energy very quickly and efficiently to ensure continuity of the power supply to essential consumers such as auxiliary machinery and thrusters upon main power failure. It will run until the standby diesel generator can start and supply the electric power to the facilities to keep the vessel in correct position under DP operation. The proposed backup method to utilize the quick and large energy storage Flywheel system can be optimized in any power system design on offshore plant.

• Journal of Mechanical Science and Technology
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• v.17 no.9
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• pp.1276-1286
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• 2003

The performance of porous bearing under different lubricants and lubricating conditions was experimentally investigated in this study. In order to carry out the experiments, a new test rig was designed to determine the tribological properties of based sintered bronze journal bearings that were manufactured by powder metallurgy (P/M) techniques. To determine the effects of lubricating conditions with and without oil supplement (OS) on the tribological characteristics of these bearings under static loading and periodic loadings, some experiments were carried out using different lubricants. In the tests, pure base oil (SAE 20W50), two fully formulated commercial engine oils (SAE20W50) and lubricating oils with commercial additive concentration ratio of 3％ were used. The worn surfaces of test bearings were examined using optical microscopy. Experimental results showed that the change in friction coefficient was more stable and in smaller magnitude under static loading than that of periodic loading. In addition, the friction coefficient and the wear rate conducted with base oil resulted in higher values than those of fully formulated oils with and without OS lubricating conditions. The experimental results obtained in this study indicated that the correct selection of lubricant and suitable running conditions were very important on the tribological characteristics of porous bearings.

• Journal of Mechanical Science and Technology
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• v.17 no.1
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• pp.129-138
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• 2003

A 1 : 20 laboratory scale test rig of a 200 MW tangentially fired boiler is built up with completely simulated structures such as platen heaters and burners. Iso-thermal turbulent flow in the boiler is mapped by 3-D PDA (Particle Dynamic Analyzer). The 3-D numerical models for the same case are proposed based on the solution of к-$\varepsilon$ model closed RANS (Reynolds time-Averaged Navier-Stokes) equations, which are written in the framework of general coordinates and discretized in the corresponding body-fitted meshes. Not only are the grid lines arranged to fit the inner/outer boundaries. but also to align with the streamlines to the best possibility in order to reduce the NDE (numerical diffusion errors). Extensive comparisons of profiles of mean velocities are carried out between experiment and calculation. Predicted velocities in burner region were quantitatively similar with measured ones, while those in other area have same tendency with experimental counterpart.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1724-1729
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• 2003

A new ground transportation system is often simulated by the wing in ground effect(WIG). Recently, several kinds of experimental and computational studies are being carried out to investigate the WIG aerodynamic characteristics which are of practical importance to develop the new ground transportation vehicle system. These works are mainly based on conventional wind tunnel tests, but many problems associated with the WIG aerodynamic characteristics can not be satisfactorily resolved. In order to develop the new ground transportation vehicle system the WIG should be further investigated. To do this, it is necessary to develop a s imulator appropriate to the WIG aerodynamics. The objective of the present study is to clarify the aerodynamic characteristics of the WIG and to develop a new experimental test rig for the investigation of the WIG aerodynamics. Some preliminary experiments are performed to investigate the usefulness of the WIG simulator.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.619-622
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• 2002

It has been recognized that the flow in the blade passage of an axial turbomachinery rotor is very complex and is influenced by various flow phenomena, of which the tip leakage flow passing through the gap between rotor blade tip and casing plays a significant role. The losses produced due to the existence of the clearance have been known to be a large contributor of the rotor overall losses. Despite several experimental studies on non-rotating blade in the cascade configuration, and on actual rotating blades, the detailed nature of the complex flow phenomena associated with tip leakage, however, remains largely unresolved. Thus, a single-stage compressor test rig was built and measurements were taken at upstream and downstream of the rotor of this compressor at the aerodynamics laboratory of University of New South Wales. A five-hole probe and a hot-wire probe were used to measure mean and fluctuating flow parameters. The results show that tip leakage losses rise rapidly beyond tip gap of 0.01 Furthermore, the present project also identifies the regions in the wake behind the rotor of the axial compressor where such losses are concentrated. These results should be useful in the better design of rotors for improved performance of axial compressor.