• Journal of KSNVE
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• v.10 no.3
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• pp.500-507
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• 2000

Dynamic forces due to mechanical and hydraulic related causes are always exerted on operating turbomachinery such as centrifugal pumps. To ensure the safety and the reliability of the pump. the magnitudes of the vibration must be kept within an acceptable limit. The focus of this paper is on the identification of the vibration behavior and the quantitative analysis of the hydraulic excitation forces. As the structure becomes more complex finite element analysis is essential to accurately predict the vibration characteristics and the excitation forces, This paper presents an experimental and analytical technique to find and solve to vibration problems in double volute double suction centrifugal pump. Measured vibration data due to the dynamic forces are presented and individual causes are identified, finally excitation forces of the pump are inversely estimated at each frequency on operating conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.27-36
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• 2004

A Numerical analysis has been used to predict the performance in the automotive water pump with double discharge single suction. The influence of parameters such as coolant flow rate, rotational speed, ratio of blade height and clearance has been investigated. Also, the prediction of hydraulic performances such as static pressure rise, shaft power, hydraulic power and pump efficiency is carried out on the water pump including an impeller and a volute casing. A full size water pump test bench has been developed to validate the CFD flow model. Discharge flow rate, suction pressure, discharge pressure, rotational speed and torque measurements are provided. Coolant temperature is 8$0^{\circ}C$, water tank pressure is 1 kgf/$\textrm{cm}^2$ and flow rates vary.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.585-588
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• 2002

Pump casing has blockage effects on Impeller flow in a centrifugal pump such that the flow field around volute tongue has quite large change when the impeller rotates. A double suction pump is widely used in industrial world because it has lower NPSH required than a single suction pump. Thus, in this study, the interaction between impeller and volute casing has been investigated by using CFD for a double-suction centrifugal pump. Quasi-steady method and full pump model has been employed for the numerical calculation.

• The KSFM Journal of Fluid Machinery
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• v.13 no.6
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• pp.51-56
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• 2010

A numerical simulation is carried out to investigate the effect of flow rate variation and performance characteristics of double-suction centrifugal pump. Two types of pump which have different impeller inlet breadth and curvature of the shroud line consist of six blades impeller and shroud ring. Finite-volume method with structured mesh and $k-\omega$ Shear Stress Transport turbulence model was used to guaranty more accurate prediction of turbulent flow in the pump impeller. Total head, power and overall efficiency were calculated to obtain performance characteristics of two types of pump according to the variation of flow rate. From the results, impeller having smooth curve along the shroud line obtained good performance. The lower flow rate, the more circulation region, flow unsteadiness and complicate flow pattern are observed. Complicated internal flow phenomena through impellers such as flow separation, pressure loss, flow unsteadiness and performance are investigated and discussed.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.103-110
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• 1997

A performance prediction method is presented for single(double) suction centrifugal pumps with a review of loss correlations given in the previous open literature. Most of the loss analyses mentioned in the present study are one dimensional and this paper investigates several modeling schemes and shows that a fairly good prediction can be achieved by a proper selection of the most important flow parameters resulting from a mean streamline analysis. Predictions of the trends of total head- capacity and pump efficiency-capacity curves agree well with the experimental data in almost the full range of operating conditions. The prediction method developed through this study can serve as a tool to ensure good matching between parts and it can assist the understanding of the operational characteristics of general purpose centrifugal pumps.

• Journal of the Korean Society of Combustion
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• v.7 no.2
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• pp.15-23
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• 2002

We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature. CO concentration were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$, and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

• Journal of the Korean Geotechnical Society
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• v.30 no.11
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• pp.61-69
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• 2014

In this study, the performance of group suction anchors installed in sand and subjected to pullout loading was investigated by numerical analysis. The group suction anchors consist of two or three units rigidly connected to each other in parallel array and the pullout resistances were compared with that of a single anchor. Parametric study was performed using numerical models to study the effect of the physical conditions of the group anchor. The parameters include the skirt length to diameter ratio of a unit suction anchor, the pad-eye location, inclination of loading and the spacing between unit suction anchors. The analysis shows that the ratios of the pullout capacity of double suction anchor and triple suction anchor to that of single anchor are 1.7 and 2.4, respectively. The ratio increases with the increase in the spacing between the unit anchors. The other parameters such as the skirt length to the diameter ratio, the location of the pad-eye and the loading inclination have negligible effect on the ratio of pullout resistances of the group anchor to the single anchor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.10
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• pp.7-15
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• 2006

The effects of strake incidence-angle on the vortex characteristics and the wing-surface pressure distribution for a double-delta wing with strake were investigated experimentally. The strake incidence-angle of negative sign(strake is pitched down from the main-wing upper-surface) increased the suction pressure of the wing-upper surface, which was the same effect of increase of angle of attack. This change of the suction pressure was caused by the closer movement of the vortex cores to the wing upper surface rather than the increase of the vortex strength.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.143-148
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• 2001

We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature, CO values were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$ and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

• The KSFM Journal of Fluid Machinery
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• v.5 no.3 s.16
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• pp.15-24
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• 2002

This paper presents an experimental study on the unsteady flow phenomena such as leakage flow and rotating stall which have influences on the performance and stability of an axial flow fan. For this study, unsteady pressure were measured using high frequency pressure transducers mounted on the easing wall of rotor passage and analyzed by Double Phase-Locked Averaging Technique. As the flow rate was reduced to near stall point, the pressure difference between the pressure and the suction side of the blade was increased especially new the leading edge and the lowest pressure zone of suction side was gradually developed. From the result of unsteady pressure field on the casing wall, one period of rotating stall was divided into three zones and the flow characteristics on each zone were described in detail.