[en] Ultrasonic cleaning is performed by cavitation which is caused by the change of the sound pressure due to the vibration in a cleaning tank. In this study, experiments on electric power and sound pressure with various temperatures, dissolved oxygen and the level of the fluid was done in order to find out how the changes in a cleaning tank affect cavitation. As a result of a series of experiments, we found that transducer impedance changes periodically in response to the variances of fluid and have a direct influence on cleaning efficiency

[en] Check valve performance evaluation and diagnosis technology have been introduced. In performance evaluation, disc stability analysis, wear prediction and fatigue prediction technology are explained. In diagnosis technology, acoustic, magnetic, ultrasonic testing, radiography and thermography technology are explained. Finally, condition monitoring program which integrate performance evaluation and diagnosis technology are recommended based on risk-informed application

[en] Amount of electricity which product generator decide control valve at turbine. Operating method of control valve have two mode. First operating method is partial arc admission, and second operating method is full arc admission. Failure of control valve have on serious damage electricity lineage. In this paper, We have investigated resonance that control valve spring casing

[en] This proceedings contains articles of 2004 spring annual meeting of the Korean Society of Mechanical Engineers. It was held on Apr 28-30, 2004 in Pyeongchang, Korea. This proceedings are comprised of 12 sessions. The main subject titles of session are as follows: stress analysis, fracture mechanics, design, mechanical structures, dynamics, heat transfer, combustion, fluid mechanics, boilers, pressure vessles, energy supplies (Yi, J. H.)

[en] New method for the design, fabrication, and calibration of micro-machined heat flux sensor has been developed. Two types of micro-machined heat flux sensor having different thicknesses of the thermal-resistance layer are fabricated using the MEMS technique. Photo-resist patterning using a chrome mask, bulk-etching and copper-nickel sputtering using a shadow mask are applied to make heat flux sensors, which are calibrated in the convection-type heat flux calibration facility. The sensitivity of the device varies with thermal-resistance layer, and hence can be used to measure the heat flux in heat-transfer phenomena

[en] An immersed boundary method for simulation of density-stratified flows is developed and applied to computation of viscous flows over two-dimensional obstacles in a bounded domain under stable density stratification. Density sources/sinks are introduced on the body surface. Two obstacle shapes are used, a vertical barrier and a smooth cosine-shaped hill; weak stratification, defined by K=ND/πU≤1, where U, N, and D are the upstream velocity, buoyancy frequency, and domain height, respectively, is considered. The results are consistent with other author's calculations, and shed light on computation of density-stratified flows in complex geometries

[en] Diffuser is an important fluid-mechanical equipment to convert kinetic energy into pressure energy. Many of the experimental and theoretical researches have been done in a diffuser but the understanding of energy transfer and detailed mechanism of energy dissipation is unclear. In this study, computations were performed using a numerical method with SIMPLE algorithm for conical diffuser with various diffuser angles and diffuser lengths. Also, we investigated the pressure recovery coefficient in conical diffuser by inserting strut. In this paper, we showed that the strut can cause a rising pressure recovery

[en] KAERI has contrived 16 kinds of spacer grid shapes of its own since 1997 and applied for domestic and foreign patents. To date, KAERI has obtained US and ROK patents for 11 kinds of spacer grid shapes among them and the others are under review in USA, EC, China, and ROK. In this study, detailed performance analysis and test on two spacer grid shapes that are assumed to be the most effective candidates for the spacer grid of the next generation nuclear fuel in Korea was carried out. The result has shown that the performances of the candidates are better or not worse than those of the current spacer grid

[en] KIMM(Korea Institute of Machinery and Materials) has been preparing the MOV(Motor-Operated Valve) actuator testing equipment for building up nuclear environmental qualification. In this paper, a newly developed equipment will be introduced, especially including technics such as MCC(Motor Control Center) analysis and SAM(Signature Analysis Module). We expect that it will be widely used for developing the related technics

[en] This paper presents the adjoint variable Design Sensitivity Analysis (DSA) for thermal systems considering both conduction and convection heat transfer. Both nodal temperature and total heat flow are considered to be objective functions and design sensitivity formulas are derived for each case. For the case of convection heat transfer, the adjoint analysis is carefully proceeded to obtain a precise result. A topology optimization example is examined for a simple planar square plate in order to design a heat exchanger as verification