• 유체기계공업학회:학술대회논문집
• /
• 1997.02a
• /
• pp.188-195
• /
• 1997

The application of PIV to the studies of fluid-machines, especially focused on turbo-machinery is reviewed by scrutinizing the previous investigation. Owing to the inevitable high-speed analysis of turbo-machinery consisting of rotating impellers, the importance of optical setups to cope with illumination problem is frequently mentioned as main ingredient affecting the PIV performance. And the acquisition of the relative velocity and absolute velocity is determined mainly by the optical recording conditions. A few studies cast satisfactory extension of the PIV data to quantitative pressure estimation and related noise assessment.

• Journal of computational fluids engineering
• /
• v.21 no.1
• /
• pp.103-109
• /
• 2016

With the rapid increase in the number of patients with cardiopulmonary diseases, more cardiopulmonary circulatory assist devices are also needed. These devices can be employed when heart and/or lung function poorly. Due to the critical role they take, these devices have to be designed optimally from both mechanical and biomechanical aspects. This paper presents the CFD results of a baseline model of a centrifugal blood pump for the ECMO condition. The details of flow characteristics of the baseline model together with the performance curves and the modified index of hemolysis(MIH) are investigated. Then, the geometry of baseline impeller and the volute are modified in order to improve the biomechanical performance and reduce the MIH value. The numerical simulations of two cases represent that when impeller radius and prime volume decrease the MIH value also decreases. In addition, the modified geometry shows more uniform pressure distribution inside the volute. The findings provide valuable information for further modification and improvement of centrifugal blood pumps from both mechanical and biomechanical aspects.

• Nuclear Engineering and Technology
• /
• v.53 no.7
• /
• pp.2207-2220
• /
• 2021

Lead alloy is used as coolant in Lead-based cooled Fast Reactor (LFR). The natural characteristics of lead alloy are combined with the simple structural design of LFR. This constitutes the inherent safety characteristics of LFR. The main work of this paper is to take the main coolant pump (MCP) in the lead-cooled fast reactor (LFR) as the research object, and to study the flow pattern distribution of the internal flow field under the reverse rotation pump condition, the reverse rotation positive-flow braking condition and the reverse rotation negative-flow braking condition. In this paper, the double-outlet volute type and the space guide vane are selected as the potential designs of the CLEAR-I MCP. In this paper, the CFD method is used to study the potential reverse accident of the MCP. It is found that the highest flow velocity in the impeller appears at the impeller outlet, and the Q-H curves of the two design programs basically coincide. The space guide vane type MCP has better hydraulic performance under the reverse rotation positive-flow condition, the Q-H curves of the two designs gradually separate with increasing flow rate, and the maximum flow velocity inside the space guide vane type MCP is obviously lower than that of the double-outlet volute type. For the reverse rotation test of MCP, only the condition of the forward rotating pump of the main coolant pump is tested and verified. For the simulation of the MCP in LBE medium, it proved that the turbulence model and basic settings selected in the simulation are reliable.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.672-677
• /
• 2001

This study has been conducted to design the high efficiency centrifugal compressor for a HFC-134a. The 2-stage centrifugal compressor consists of inlet guide vanes, two impellers with splitters, a deswirler, a vaneless diffuser and a volute casing. We have designed the high efficiency centrifugal compressor by applying the repeated design procedure including a meanline design, a 3D geometry generation of 1st and 2nd impellers etc. Also, a fluid dynamic calculation of impellers and deswirler have been conducting using a commercial code STAR-CD.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1395-1400
• /
• 2004

A centrifugal compressor for geothermal heat pump system using R134a as working fluid has been developed. The centrifugal compressor consists of an impeller with splitters, two vaneless diffuser, a low solidity vaned diffuser and a volute. In this compressor, diffuser blade angles are controlled to satisfy both heating and cooling conditions. A aerodynamic design was done by applying the repeating design procedure including a meanline design, a 3D geometry generation and fluid dynamic calculation. In this paper, design and performance prediction results of the compressor are presented.

• The Korean Journal of Food And Nutrition
• /
• v.14 no.4
• /
• pp.317-321
• /
• 2001

Sweet dough bread is made by using sponge & dough method with the sweet dough formula which consists of wheat gluten and baking powder. The effect of wheat gluten and baking powder to the bread has been studied after the dough frozen, stored, thawed, fermented. and baked. The bread quality has been evaluated by measuring the product volute and also by the sensory evaluation after baking. When 4% of wheat gluten and 4% of baking powder were added into the dough. the bread has a larger volume than that of 2% wheat gluten and 2% baking powder in volume. However. wheat gluten shows better result than baking powder in terms of volume. In sensory evaluation, the bread has higher score when 2% of wheat gluten and 2% of baking powder were added into the dough than that of 4% wheat gluten and 4% baking powder. Consequently, breads show better result when 2% wheat gluten and 2% baking powder were added into the dough than that of 4% wheat gluten and 4% baking powder.

• The Korean Journal of Food And Nutrition
• /
• v.14 no.4
• /
• pp.311-316
• /
• 2001

This study was designed to investigate the effective ratio of healthy bread wish green tea powder. The weight. volume, and colon difference of bread with various contents of green tea powder were measured. And the picture of bread and the panel test were taken. To avoid the decrease of volume, the experiment was taken with active gluten. The weight to bread was increased and the volume was decreased significantly according to increase of green tea powder ratio. But, the volume of the group with active gluten(3%+ and 4%+) was higher than that of the group with green tea powder 2%. That is which the correction of the volute was taken by active gluten in green tea powder bread. In the result of panel test and volume measurement. addition of 3% green tea powder was appropriate, and the addition of active gluten corrected the decrease of volume. Therefore. using the green tea powder, the diversity of bread by functionality, nutritional composition. taste, color. flavor of green tea powder can be developed. This result will support the background the development of green tea bread of good quality.

• The KSFM Journal of Fluid Machinery
• /
• v.6 no.4 s.21
• /
• pp.7-13
• /
• 2003

Flow characteristics of an automotive oil pump of gerotor type have been investigated numerically. For the simulation of a gerotor whose inner and outer rotors rotate at different speeds, node expansion and contraction method was adopted. ASI (Arbitrary Sliding Interfaces) method was also applied at interface between rotating gerotor and stationary volute. Studied are the flow rates depending on various gerotor in the gap are also studied. The present results showed good agreement with the experimental data.

• The KSFM Journal of Fluid Machinery
• /
• v.9 no.2 s.35
• /
• pp.39-43
• /
• 2006

The magnitude of the axial force acting on turbopump bearings has a great influence on the operational reliability and service life of a turbopump. In the turbopump under current investigation the cavity vanes are introduced to the pump shroud casing to control the axial thrust of the turbopump. To investigate the effect of the cavity vanes, 3D computational flow analyses for a propellant pump stage including an inducer, impeller, volute and secondary flow passages are performed with and without the vanes. The results show that the cavity vanes are very effective in reducing the magnitude of axial thrust without notable changes on the overall performance of the turbopump.

• Journal of Energy Engineering
• /
• v.10 no.4
• /
• pp.335-341
• /
• 2001

Pressure pulsations generated by the blade-tongue interaction induce vibration of the piping systems and the structure connected to pumps, resulting in the severe noise and fatigue fracture. Experiments were made on the natural frequencies of liquid columns in piping systems with a single suction, single stage, centrifugal volute pump. Experimental results show that the natural frequencies of the liquid columns in the pump piping systems depend on the dimensions of the pipes and the impeller shapes, and are not affected substantially by the rate of discharge and the rotating speed of the pump.