• The KSFM Journal of Fluid Machinery
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• v.6 no.2 s.19
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• pp.41-46
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• 2003

The hydraulic design optimization and performance analysis of mixed-flow pumps for waterjet marine vehicle propulsion has been carried out using mean streamline analysis and three-dimensional computational fluid dynamics (CFD) code. In the present study, the conceptual design optimization has been formulated with a non-linear objective function to minimize the fluid dynamic losses, and then the commercial CFD code was incorporated to allow for detailed flow dynamic phenomena in the pump system. Newly designed mixed-flow model pump has been tested in the laboratory. Predicted performance curves by the CFD code agree very well with experimental data for a newly designed mixed-flow pump over the normal operating conditions. The design and prediction method presented herein can be used efficiently as a unified hydraulic design process of mired-flow pumps for waterjet marine vehicle propulsion.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.75-81
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• 2000

Experimental studies on the characteristics of annular jet pump were carried out in this paper. The effects of high pressure chamber on the characteristics of annular jet pump were sought in this paper. Experiments were done for three shapes of high pressure chamber, and for several lengths of the high pressure chamber. Three types of the high pressure chamber's entrances($90^{\circ}$ single inflow, $45^{\circ}$ single inflow, and $45^{\circ}$ double inflow) were tested. Water was used for both the primary fluid and secondary fluid. The results obtained in this study are as follows; $45^{\circ}$ double inflow type is the most effective among the tested three types of the high pressure chamber's entrances. The efficiency of jet pump with 400mm of high pressure chamber length is the highest among the chamber lengths tested in this study, thus indicating appropriate chamber length is required to get an efficient jet pump.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.162-167
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• 2000

Construction machinery includes an engine enclosure separated from a cooling system enclosure by a wall to reduce noise and advance cooling system performance. For this structure, however, the axial fan cannot be of benefit to the engine room, and so the temperature rise in the engine room makes several bad conditions. This paper proposes that hot air in engine room is evacuated tv secondary pipe using jet pump. This paper demonstrates the structure and the effect of jet pump and useful guideline on design of area, length, and shape of secondary pipe to maximize the effect of jet pump.

• Journal of Power System Engineering
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• v.5 no.1
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• pp.50-56
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• 2001

Jet pumps are used in a great number of engineering applications. In the present study, jet shapes, mixing chamber shapes, and numerical methods for predicting the performance of an annular-type jet pump are investigated to determine the optimal turbulence model. The flow fields are simulated by solving the momentum and the continuity equations with the standard ${\kappa}-{\epsilon}$ and the RNG ${\kappa}-{\epsilon}$ turbulence models at different Reynolds numbers. After that, they are compared with the corresponding experimental data to determine the optimal model. Next, various calculations are conducted to find an optimal shape using the selected turbulence model. The study shows us that the RNG ${\kappa}-{\epsilon}$ model predicts the performance more exactly, and also shows that the most effective performance can be achieved with $12^{\circ}$ reducing angle and 130mm throat length.

• Journal of Power System Engineering
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• v.3 no.1
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• pp.23-28
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• 1999

Experimental and theoretical researches about jet pump have been carried out by many researchers. Jet pump can be used for the transportation of solid materials, farm produce, and fishes. It is the purpose of this paper to seek optimal multi nozzle shape of the annular jet pump. Experiments were done for several jet nozzle areas, jet nozzle arrays and jet nozzle lengths. Water was used for both the primary fluid and secondary fluid. The efficiency curves for the annular jet pump having multi nozzles are presented in this paper.

• Journal of Power System Engineering
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• v.4 no.1
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• pp.33-38
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• 2000

The characteristics of center-driver jet pump which have multi-nozzle were studied in this research. Jet nozzles are connected outside of the bend rather than inserted in the bend in order to transport solid materials or fish without any harm. Jet pumps having one nozzle, two nozzles, four nozzles, and sixteen nozzles were tested in this study. The efficiencies and performances of jet pumps were studied for several nozzles shape, for three different mixing chamber shapes, for two suction area shapes. All the efficiency curves for these cases are presented in this paper.

• Journal of Power System Engineering
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• v.1 no.1
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• pp.35-41
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• 1997

Annular jet pump can be used for the transportation of solid materials and fish. The effect of mixing chamber on the characteristics of annular jet pump is sought in this paper. Experiments were done for several reducing angles of mixing chamber, and for several throat area. Water was used for both the primary fluid and secondary fluid. A vortex was observed for the straight mixing chamber, but it was not observed for the mixing chamber whose reducing angle is $18^{\circ}$ or higher. The efficiency curves for the annular jet pump are presented in this paper, showing the annular jet pump which has 240 reducing angle and $0.611{\sim}0.73$ value of At/As. is most effective among the tested several annular jet pumps.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.4
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• pp.442-449
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• 1998

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.246-252
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• 2014

This study is on the development of 150PS inboard type of compact water jet propulsion system. The water jet is composed of intake, impeller, diffuser, reverse bucket and main shaft. Components of water jet have been manufactured through precision processing after sand casting. Development of water jet propelled engine has been finally completed by processes which are design, production and inspection on each component. The water jet performance characteristics show that 0.29 m3/s of maximum flow rate and 37 m/s of flow velocity have been secured in the ground test pool. Field test was performed by 21ft test ship that water jet propulsion equipment developed in this study was installed. As a result, the weight of hull, engine and other parts of the ship has been almost 1.2 ton and 45 km/h of maximum sailing speed has been recorded with 3700 rpm of engine in the domestic coast test.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.2
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• pp.107-116
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• 2008

The jet pumps are widely used to transfer the fuel between the tanks in an aircraft fuel supply system. However detailed design procedures for determining the size of components of the jet pumps are not known so well. In this paper, the flow characteristics of the jet pump, which is applied in the fuel transfer system for the smart UAV (Unmanned Aerial Vehicle), were experimentally investigated using the acrylic jet pump model for the visualization of the internal flow. The pressure distributions within the jet pump were measured, and then the loss coefficients of each part were calculated. The effects of Reynolds number and the distances (S) between the exit of the primary nozzle and the mixing chamber entrance were investigated. In addition, cavitation phenomena were considered through the flow visualization inside the jet pump. As a conclusion from the experiment, the contraction shape of the primary nozzle has a strong effect on the loss coefficient of the nozzle and the cavitation occurrence. Cavitation starts around the nozzle exit, and then it propagates to the full flow fields of the jet pump.