• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.141-145
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• 2003

The FBG sensors are inserted on the liners of the filament wound pressure tanks. The strains near the welding region of the liners are monitored in the hydro-pressurizing tests. The hydro-pressurizing tests consist of the proof tests at 4500 or 3300 psi and repeated test at the operating pressure, 3000 psi. The FBG sensors work well under $3000\mu\varepsilon$, but the strains calculated from the reflected signals are instable at the high strain level. The transverse compression on the sensor head results in the split of the reflected peaks, and the calculating algorism from the split peaks is not robust under the various signal condition. The FBG sensors fracture near $7500\mu\varepsilon$ level and lose their function permanently.

• Journal of Mechanical Science and Technology
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• v.15 no.12
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• pp.1728-1738
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• 2001

Measurements have been made in an automotive HVAC b1ower for two different centrifugal fans. This work is directed at improving the performance of a conventional forward-curved centrifugal fan for a given small blower casing. Mean velocities and pressure have been measured using a miniature five-hole probe and a pressure scanning unit connected to an online data acquisition system. First, we obtained the fan performance versus flow rates showing a significant attenuation of unstable nature achieved with the new fan rotor in the surging operation range. Second, aerodynamic characterizations were carried out by investigating the velocity and pressure fields in the casing flow passage for different fan operating conditions. The measurements stowed that performance coefficients are strongly influenced by flow characteristics at the throat region. The main flow features ware common in both fans, but improved performance is achieved with tole new fan rotor, particularly in lower flow rate legions. Based on the measured results, design improvements were carried out in an acceptable operation range, which gave considerable insight into what features of flow behavior ware most important.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.2
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• pp.48-55
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• 2001

An accumulator in hydraulic systems stores kinetic energy during braking action, and then that control hasty surge pres-sure. This study suggests a method to select the capacity of accumulator to control surge pressure to a desired degree. The selection method is based upon a trial and error approach and computer simulation. A mathematical dynamic model of the system was derived and the parameters in the model were identified from experimental data. A series of computer simulation were done for the brake action. The results of the simulation work were compared with those of experiments. These results of the computer simular-tion and experiments show that the proposed method can be applied effectively to control the surge pressure of the hydraulic regenerative brake systems.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.448-455
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• 2020

The H.B. Robinson Unit 2 (HBR-2) pressure vessel dosimetry benchmark is an in- and ex-Reactor Pressure Vessel (RPV) neutron dosimetry benchmark based on experimental data from the HBR-2 reactor, a 2300-MW PWR designed by Westinghouse and put in operation in March 1971, openly available through the SINBAD Database at OECD/NEA data Bank. The goals of the present work were to carry out three-dimensional (3D) fixed source transport calculations in both Cartesian (X,Y,Z) and cylindrical (R,θ,Z) geometries by using the TORT-3.2 discrete ordinates code on very detailed 3D HBR-2 geometrical models and to test the latest broad-group coupled (47 neutron groups + 20 photon groups) working cross section libraries in FIDO-ANISN format with same structure as BUGLE-96, such as BUGJEFF311.BOLIB, BUGENDF70.BOLIB and BUGLE-B7. The results obtained with all the cited libraries were satisfactory and are here reported and compared.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.102-107
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• 2001

Recently, with the increasing of construction works, large construction equipment are used to reduce the term of work and labor cost in construction field. Therefore, construction equipment noise has caused much annoyance for a number of dweller in nearby construction field and it has become a very serious problem in our living environment. Neverthless, in our country, adequite guidelines for the construction equipment noise are very deficiency because of the lack of basic data and insufficient research works. From this point of view, this study attempts to survey the characteristics and prediction of piling noise in oil pressure method. On the basis of measurement value, we analysed about prediction possibility of piling noise in oil pressure method.

• Tribology and Lubricants
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• v.15 no.1
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• pp.98-107
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• 1999

In this work the effect of pressure drop at inner film due to centrifugal forces acting on the lubricating fluid is investigated for static and dynamic characteristics of floating ring journal bearing. The momentum effect of oil supply into a inner film through oil feeding holes of floating ring on the bearing performance is also studied. It is compared the pressure drop effects and the momentum effect of oil supply into a inner film fur all bearing performance parameters. It is shown that some performance of floating ring bearings can be controled by the momentum of oil supply into a inner film.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.305-310
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• 2008

This paper provides the methods to estimate the burst pressures of the pipes with defects, based on finite element analyses. FE codes are frequently adopted for the simulations of the burst tests of the pipes with defects. However, those do not give the burst pressure directly. Because the post-processing should be followed; determination of the fracture strains in accordance with triaxialities, monitoring the strains of pipes, etc. In the present work, these efforts are implemented in the user subroutine UHARD within the general-purpose FE code, ABAQUS. Four fracture criterions are introduced to estimate the burst pressure of pipes, and a simple fracture strain estimate is also developed. FE analyses for the pipe with gouge and corrosion are performed, and the results are compared with the experiment results.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.892-898
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• 2000

This study is on the development of a new muffler composed of a valve system using an elasticity or spring. The valve system using the elasticity of spring is set along the exhaust-gas flow and designed to work itself alone the driving condition of a engine. By that reason the engine capacity is so enlarged that a muffler with controller sensing exhaust-gas pressure is able to be satisfied to noise reduction and- power enlargement more than conventional muffler. The purpose of this study is to develope the new muffler which has more noise reduction and power enlargement than conventional muffler and electric-control muffler.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.101-104
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• 2012

In this work, in-cylinder pressure measurements and high-speed direct imaging of the flame were performed in an optically accessible single cylinder diesel engine with premixed charge compression ignition combustion and a narrow injection angle. The results show that the frequency ranges of pressure ringing were 8.35 to 9 kHz and 12..2 to 13.1 kHz. The frequencies of the flame movement were shown as 8.7 kHz and 13 kHz. It was found that there is a direct relationship between the pressure ringing and the flame movement.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.36-43
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• 2012

In this work the mixing and flow characteristics of a vane-type static mixer were investigated numerically for the reduction of NOx in the SCR-system of the diesel engines. The mixer was located in the 57 times pipe diameter away from the inlet. The analysis were performed by changing such various parameters as vane shape, angles, blockage ratio and location of the vane. The flow structure through the mixer was characterized by uniformity index and pressure drop. The results show that uniformity index and pressure coefficient are substantially influenced by the vane shape, angle, blockage ratio and position of the vane of the mixer.