• Journal of the Korean Society of Safety
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• v.13 no.3
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• pp.51-59
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• 1998

The vortex tube is a simple device for separating a compressed fluid stream into two flows of high and low temperature without any chemical reactions. Recently, vortex tube is widely used to local cooler of industrial equipments and air conditioner for special purpose. The phenomena of energy separation through the vortex tube were investigated to see the effects of cold flow inlet-outlet ratios and partial admission rates on the energy separation experimentally. The experiment was carried out with various cold flow inlet-outlet ratios from 0.28 to 10.56 and partial admission rates from 0.176 to 0.956 by varying input pressure and cold air flow ratio. To find best use in a given cold flow inlet-outlet ratio and partial admission rate, the maximum temperature difference of cold air was presented. The experimental results were indicated that there are an optimum range of cold flow inlet-outlet ratio for each partial admission rate and available partial admission rate.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.136-142
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• 2021

Submerged and semi-submerged vehicles expel cooling water through an outlet. In this process, induced noise and vibration by the flow around the outlet have been reported, and it may cause problems directly related to survivability of the navy vessels. The coolant outlet has a net-type structure and circular columns are mostly used. In this study, flow measurements using PIV and LDV were performed for different type outlets; conventional (flat plate with round bar) and improved (flat and flat plate) configurations. Experiments were conducted at a cavitation tunnel where pressure and steady flow rate conditions are ensured for sufficient time to measure the flow. The average velocity field of the outlets were measured and compared through LDV measurements, and instantaneous vorticities were evaluated through PIV measurements. The results show that the improved type of the outlet is advantageous in terms of flow stability compared to the conventional type of the outlet.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.5
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• pp.514-525
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• 2023

This study conducted numerical simulations with the purpose of analyzing the impact of variations in outlet pressure conditions under extreme temperature conditions on the fluid dynamics and performance of a check valve utilized in hydrogen refueling systems. Under the extreme temperature conditions, changes in outlet pressure conditions of the check valve were investigated to analyze velocity distributions, pressure distributions, and temperature distributions in the operational and connection regions. The analysis results indicated that changes in outlet pressure had a significant influence on the internal temperature variation of the check valve. Furthermore, due to density variations in the connection region caused by the cooling effect of excessively cooled hydrogen, a bias in the primary flow direction towards the lower part of the valve outlet was observed in the outlet area. Through a comparison of the results of the valve's inherent flow performance, represented by the flow coefficient, it was observed that when the pressure difference between the inlet and outlet was below 0.37 MPa, sufficient flow was not ensured.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.60.4-60
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• 2002

Nonlinear adaptive control for the laboratory pressure-flow model. Control valves are installed on both sides. The pressure and the outlet flow rate are measured. The pressure and outlet flow rate are controlled variables and the control valve stem positions on both sides are the manipulated variables. The variation in both inputs will influence both controlled variables. The control performance is good, in spite of varying valve coefficients of inlet and outlet.

• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.72-77
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• 2014

Because of overload working condition of sintering cooler, the cooler fan often suffers the break or damage of rotor blade and fixing shaft. Therefore, internal flow characteristics of a steelworks sintering cooler fan by the duct shape of the cooler fan outlet, such as duct outlet opening ratio, duct height and dividing wall shape on the duct outlet flow pattern are examined in detail. The results show that relatively short duct wall height and attachment of dividing wall shape improves flow patterns considerably.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.7
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• pp.549-556
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• 2001

Heat flow characteristics during hot water extraction process was studied experimentally. Data were taken at various outlet port type for the fixed inlet port type, inlet-outlet temperature differences and mass flow rates. In this study, the temperature distribution in a storage tank and an outlet temperature were measured to predict a flow pattern in the storage tank, and a hot water extraction efficiency was analysed with respect to the variables dominating a extraction process. Experimental results show that the extraction efficiency is high in a low flow rate in case of using modified distributor I(MDI) as a outlet port type.

• Journal of the Korean Society of Visualization
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• v.12 no.1
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• pp.25-29
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• 2014

The outlet flow of the centrifugal blower were quantitatively visualized using particle image velocimetry. Because the centrifugal blower is one of the key parts of electric vehicle battery cooling system, the quantitative information of centrifugal blower is necessary to design and optimize the cooling system. The effect of different inlet flow condition to the outlet flow was investigated in this study. Two different inlet ducts were used. One is the straight inlet and the other is a bended one. The results clearly showed the outlet flow asymmetry in both inlet ducts. When the blower has the bended inlet, the flow rate decreases due to the increase of the head loss.

• Journal of the Korean Society of Visualization
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• v.22 no.2
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• pp.55-62
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• 2024

Using an internal flow noise test bench, this study investigates the variation in internal flow noise at the inlet and outlet monitoring points of a DN100 T-junction pipe under different flow velocities. Results indicate that with increasing flow velocity, both the sound pressure level and total sound pressure level at the inlet and outlet monitoring points increase. The highest total sound pressure level is observed at the vertical outlet monitoring point B, followed by the horizontal inlet monitoring point A, with the lowest at the horizontal outlet monitoring point C. At a constant flow velocity, the sound pressure level at the inlet and outlet points initially increases and then decreases as frequency increases.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.9
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• pp.491-496
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• 2015

Generally, the phase of the refrigerants that circulate in air-conditioning systems is repeatedly changed from liquid to gas and from gas to liquid. In vapor-compression refrigeration, the refrigerant at the inlet of the evaporator is in a gas-liquid two-phase state; therefore, to enhance the heat-transfer performance of the evaporator, the even distribution of the refrigerant across multiple passages of the evaporator is essential. Unlike the distribution of a single-phase refrigerant, multi-phase distribution requires further considerations. It is known that the multi-phase distribution at the outlet of the distributor is affected by factors such as the operating condition, the distributor's shape, and the insertion depth of the outlet pipes; here, the insertion depth of the outlet pipes is especially significant. In this study, for a cylindrical distributor with a 90-degree bend entrance and three outlet pipes, the flow uniformity at the outlet pipes was numerically tested in relation to variations of the insertion depth of the outlet pipes.

• International Journal of Fluid Machinery and Systems
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• v.4 no.3
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• pp.317-323
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• 2011

Mini centrifugal pumps having a diameter smaller than 100mm are employed in many fields; automobile radiator pump, ventricular assist pump, cooling pump for electric devices and so on. Further, the needs for mini centrifugal pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini centrifugal pump design be as simple as possible as precise manufacturing is required. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, we started research on the mini centrifugal pump for the purpose of development of high performance mini centrifugal pumps with simple structure. Three types of rotors with different outlet angles are prepared for an experiment. The performance tests are conducted with these rotors in order to investigate the effect of the outlet angle on performance and internal flow condition of mini centrifugal pumps. In addition to that, the blade thickness is changed because blockage effect in the mini centrifugal pump becomes relatively larger than that of conventional pumps. On the other hand, a three dimensional steady numerical flow analysis is conducted with the commercial code (ANSYS-Fluent) to investigate the internal flow condition. It is clarified from the experimental results that head of the mini centrifugal pump increases according to the increase of the blade outlet angle and the decrease of the blade thickness. In the present paper, the performance of the mini centrifugal pump is shown and the internal flow condition is clarified with the results of the experiment and the numerical flow analysis. Furthermore, the effects of the blade outlet angle and the blade thickness on the performance are investigated and the internal flow of each type of rotor is clarified by the numerical analysis results.