• International Journal of Fluid Machinery and Systems
• /
• v.4 no.1
• /
• pp.191-198
• /
• 2011

Based on the consideration that the cavitation would affect the operation stability of miniature pumps, the 3-D turbulent cavitating flow in a test pump was simulated by using a mixed cavitation model and k-${\omega}$ SST turbulence model. In order to investigate the influence of inlet geometry parameters on the cavitation performance of the miniature pump, two more impellers are designed for comparison. Based on the results, the following conclusions are drawn: 1) Cavitation performance of the double suction shaft-less miniature pump having different impeller is equivalent to the centrifugal pump having ordinary size, though the flow passage at impeller inlet is small; 2) The miniature pump having radial impeller can produce much higher pump head, but lower cavitation performance than that having the impeller based on the conventional design method; 3) It is believed that by applying the double suction design, the miniature pump achieved relatively uniform flow pattern upstream the impeller inlet, which is favorable for improving cavitation performance.

• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3549-3558
• /
• 2023

The jet pump can be used in a test device of a nuclear reactor for high flow amplification as it reduces inlet flow requirement and thereby size of the process components. In the present work, a miniature jet pump was designed to meet high flow amplification greater than 3. Subsequently, experiments were carried out using a test setup for design validation and performance evaluation of the jet pump for different parameters. It was observed that a minimum pressure of 0.6 bar (g) was required for the secondary fluid inside the jet pump to ensure cavitation free performance at high amplification. Spacing between the nozzle tip and the mixing chamber entry point had significant effect on the performance of the jet pump. Variation in primary flow, temperature and area ratio also affected the performance. It was observed that at high flow amplification, the analytical solution differed significantly from experimental results due to very large velocities encountered in the miniature size jet pump.

• International Journal of Fluid Machinery and Systems
• /
• v.7 no.4
• /
• pp.142-150
• /
• 2014

In the cardiopulmonary support system with an ECMO (extracorporeal membrane oxygenation), a higher pump head is demanded for a blood pump. In order to realize a blood pump with higher pump head, higher anti-hemolysis and thrombosis performances, a study on the development of unprecedented multistage blood pump was conducted. In consideration of the application of the blood pump for pediatric patients, a miniature two-stage centrifugal blood pump with the impeller's diameter of 40mm was designed and the performance was examined in experiments and computations. Some useful knowledge for a design of the blood pump with higher anti-hemolysis and thrombosis performances was obtained.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.3
• /
• pp.27-32
• /
• 2010

The OMM(On-Machine-Measurement) system has many advantages compare to conventional measurement in the way the time and cost. But, the sensor suitable to OMM system is restrictive use. Touch trigger probe sensor has long time for measurement and non-contact sensor has directional demerit. Because the long mechanical parts such as gear and lead screw for pump, injector and machine tools has big and heavy, unclamp and transferring for measurement in machining process is very difficult. This paper presents a development of ultra miniature eddy current displacement sensor with 3 axes for On-Machine-Measurement system. The accuracy of the sensor is experimentally proved in the grinding machine. In experimental results, the accuracy has under ${\pm}5\;{\mu}m$.

• The Journal of Korea Robotics Society
• /
• v.16 no.2
• /
• pp.79-85
• /
• 2021

Soft fluidic actuators (SFAs) are widely utilized in various areas such as wearable systems due to the inherent compliance which allows safe and flexible interaction. However, SFA-driven systems generally require a large pump, multiple valves and tubes, which hinders to develop a miniaturized system with small range of motion. Thus, a highly integrated soft actuator needs to be developed for implementing a compact SFA-driven system. In this study, we propose an electro-hydraulic soft zipping actuator that can be used as a miniature pump. This actuator exerts tactile force as a dielectric liquid contained inside the actuator pressurized its deformable part. In addition, the proposed actuator can estimate the internal dielectric liquid thickness by using its self-sensing function. Besides, the electrical characteristics and driving performance of the proposed system were verified through experiments.

• Journal of Sensor Science and Technology
• /
• v.28 no.1
• /
• pp.52-57
• /
• 2019

Studies to augment emotion and immersion in multimedia content through olfactory stimulation are being increasingly conducted in the past two decades, and a variety of scent devices have been developed. Most of the scent devices are very large and heavy; consequently, they are installed on a table rather than being attached to the Head-mounted Display (HMD). Even if such devices are mounted on the HMD, it is not possible to control the scent density because of the size limitation, and it is not easy to be immersed in the experience because of the noise caused by the scent device. In order for an actual virtual reality or an augmented reality system to work efficiently with the scent device, three conditions - noiseless, a compact design, and concentration control- must be satisfied. In this study, we design a scent device that satisfies these three conditions. By using a miniature piezoelectric pump, a small size scent device is designed so that it can be easily attached to the lower end of the HMD, and hardly any noise is generated. Moreover, it is possible to control the concentration of the scent by controlling the piezoelectric pump using amplitude and frequency.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.3
• /
• pp.207-216
• /
• 2016

A gerotor is suitable for miniature manufacturing because it has high discharge per 1 cycle and a simple structure, while also being widely used for lubrication oil of engines and as a hydraulic source of automatic transmission. In the automobile industry, improvements in fuel efficiency and noise reduction have recently come to the fore. It has also been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor and port shape design. In this study, to develop an optimal gerotor with a new lobe shape, 2-ellipses-combined, the equation of the lobe shape was derived, and CFD analysis results were compared for 2-ellipses with those of the previous gerotors (3-ellipses and ellipse1-involuteellipse2). A performance test for the oil pump with the optimal rotor (2-ellipses) was carried out and showed good agreement with the results obtained from CFD analysis.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.11
• /
• pp.927-935
• /
• 2016

A gerotor is suitable for miniature manufacturing because it has a high discharge per cycle and a simple structure, while also being widely used as lubrication oil of engines and the hydraulic source of automatic transmission. In the automobile industry, it has been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor design. In this study, to obtain an optimal gerotor with an ellipse-elliptical involute-ellipse combined lobe shape, an automatic program was developed for calculating performance parameters and drawing a gerotor profile. An oil pump was assembled with the optimal gerotor together with the port used at the actual field and CFD analysis was performed on this assembly using Ansys-CFX. A performance test for the oil pump was carried out and showed good agreement with the results obtained from the theoretical analysis and the CFD analysis.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.8 no.3
• /
• pp.295-306
• /
• 2003

Recently efforts are underway to analyze the impacts of anthropogenic $CO_2$ on the global environments and the amount of oceanic uptake increase. The East Sea is now viewed as a miniature ocean because its circulation pattern is similar to the ocean conveyer belt. The biological pump of the East Sea is a vital component to understand the carbon cycle quantitatively. In this paper, the biological pump is estimated utilizing the stoichiometric ratio between carbon and phosphorus. A simple phosphate budget model is constructed based on the seawater and dissolved oxygen box model that can simulate the recent structural change in deep water circulation of the East Sea. A model run from you 1952 to 2040 shows the steadily intensifying biological pump. Currently it exports about 0.016 Pg C yr$^{-1}$ , which corresponds to 35％ of the carbon introduced into the seawater by the air-sea exchange. An increased oxygen supply to the central water mass as a result of from the transition in the ventilation system might enhance the remineralization of sinking biogenic particles. This should strengthen the upward nutrient flux into the surface layer. Consequently, the biological sequestration of anthropogenic carbon is expected to increase with time. The estimated biological uptake of the anthropogenic carbon in the East Sea since the Industrial Revolution is estimated as 0.025 Pg C.

• Journal of Animal Science and Technology
• /
• v.46 no.4
• /
• pp.585-592
• /
• 2004

Our previous studies demonstrated that relaxin in concert with estrogen promotes development of the mammary parenchyma during the last third of gestation in gilts, and the specific relaxin-binding sites were present in the mammary gland. This study was conducted to determine if relaxin-binding sites in the mammary gland were functional relaxin receptors. Three cycling cross-bred gilts were bilaterally ovariectomized on day 0 of the experiment. Beginning on day 15 and continuing through day 29 post-surgery, the gilt received an im. injection of estradiol benzoate at 12-hr intervals. Beginning on day 22 post-surgery, highly purified porcine relaxin was administered(lug/hr) into the left fourth mammary gland from the anterior end via miniature osmotic pump. Physiological saline was administered to the right fourth mammary gland. The gilt was sacrificed on day 29 post-surgery and histological characteristics of the mammary parenchyma were examined. The mammary glands treated locally with saline showed little, if any, lobulo-alveolar development, whereas the mammary glands treated with relaxin showed not only marked lobulo-alveolar development but also prominent secretions in the alveoli. The saline-treated glands were characterized by relatively dense and highly organized collagen fiber bundles. Whereas, in the relaxin-treated mammary glands, collagen fiber bundles were dispersed and loosely organized. In conclusion, relaxin-binding sites in the mammary gland are functional relaxin receptors and relaxin acts directly on the pig mammary gland to promote development of the alveoli and remodeling of the extracellular matrix.