• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.10
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• pp.1083-1088
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• 2011

The effects of an impeller and floating ring seals on the performance of centrifugal pumps are investigated on the basis of their test results using water. The pumps are single-staged centrifugal pumps developed for 30-ton- and 75-ton-class liquid rocket engines, and are components of a turbopump that supplies propellants (liquid oxidizer and kerosene) to the combustion chamber. The exit width of the impellers and the numbers and exit angles of the impeller blades are found to have influences on the pump heads. In addition, the pumps have different efficiencies according to the gaps between the floating ring seals and the impellers, whereas the pump size seems to have less effect on the efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.879-884
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• 2002

There are screw, reciprocating and turbo compressor by structure in an air compressor, essential equipment on he industrial spot. Resently it is wide that the range of turbo compressor's use in gradual, turbo compressor needs high speed rotation of impeller in structure, high rated gearbox and conventional induction motor. This mechanical system increased the moment of inertia and mechanical friction loss. Resently the study of turbo compressor applied super high speed motor and drive, removing gearbox made its size small and mechanical friction loss minimum. In this study we tried to develope variable super high speed motor drive systems for 150Hp, 70,000rpm drect drive Turbo compressor. The result of study is applied to a 150Hp direct turbo compressor and makes it goods.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.4
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• pp.326-335
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• 2014

Aerodynamic characteristics of the small two-stage turbo blower were investigated using commercial CFD tool(ANSYS CFX Ver. 14.5) in this paper. Turbo blower, which is a centrifugal type of turbomachinery, is used in various industries. It is used for application that required high static pressure rising at relatively small volumetric flow rate. In order to understand the mechanism of static pressure rising, the aerodynamic characteristics of the small two-stage turbo blower are analyzed at high rotating speed in this study. The k-${\omega}$ SST turbulence model, which is good at prediction of adverse pressure gradient flows, was applied. The CFD results of the turbo blower are validated by performance test. The static pressure rising of the turbo blower is nonlinearly increased over the first stage and the second stage. The secondary flow occurred at guide vanes, between the casing and the first impeller shroud, and the bottom of the impeller disk. As a result, It is required that whole fluid area is analyzed to predict aerodynamic characteristics of small two-stage turbo blower. and the result should be selected with considering for error from experiment and CFD.

• The KSFM Journal of Fluid Machinery
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• v.11 no.5
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• pp.37-43
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• 2008

An inducer is employed in a modern rocket feed system because it allows a turbopump system to operate at a high speed with low inlet pressures so as to minimize the weight and the size of the system. Cavitation performance can be improved by installing an inducer to the pump, enabling to increase the operational speed of the pump. The main purpose of an inducer is to increase the static pressure prior to an impeller to enable the impeller to operate satisfactorily under cavitation environments. In the present study the effects of axial distance between the inducer and the impeller on the performance of the pump were studied using both experimental and computational methods. Two inducers with different axial length were used for the experiments and the pump performances were measured. The experimental results show that the suction performance decreases as the axial gap between the inducer and impeller is increased.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.33-40
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• 2002

The hydraulic performance analysis of a pump system composed of an inducer and impeller for the application on turbopumps has been performed using three-dimensional Wavier-Stokes equations. A simple mixing-plane method and a full interaction method are used to simulate inducer/impeller interactions. The computations adopting two methods show almost similar results due to the weak interaction between the inducer and impeller since the inducer outlet blade angle is rather small. But, because the inducer and the impeller are closely spaced near the shroud region at the interface, flow angles at the impeller inlet show different results between two methods. Thus, the full interaction method predicted about $2\%$ higher pump performance than the mixing-plane method. And the effects of prewhirl at the impeller inlet are also investigated. As the inlet flow angle is increased, the head rise and the efficiency are decreased. The computational results are compared with experimental ones. The computational results at the design point show good agreements with experimental data. But the computation was found to under-predict the head rise at high mass flow rates compared to the experiment, further study must be followed in terms of the computation and experiment.

• The KSFM Journal of Fluid Machinery
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• v.6 no.4 s.21
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• pp.50-57
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• 2003

The hydraulic performance analysis of a turbopump with an inducer for a liquid rocket engine was performed using three-dimensional Navier-Stokes equations. A simple mixing-plane method and a full interaction method were used to simulate inducer/impeller interaction. Two methods show almost similar results due to the weak interaction between the inducer and impeller since the inducer outlet blade angle is lather small. But, when the inducer and the impeller are closely spaced near the shroud region, flow angles at the impeller inlet show different results between two methods. Thus, the full interaction method predicts about $2\%$ higher pump performance than the mixing-plane method. And the effects of prewhirl at the impeller inlet are also investigated. As the inlet flow angle is increased, the head rise and the efficiency are decreased. The computational results are compared with measured ones. The computational results at the design point show good agreements with experimental data, however under-predicts the head rise at high mass flow rates compared to the experiment.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.21-28
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• 2014

Propellent should be pressurized inside the turbopump to gain high thrust in a projectile. Turbopump is composed of an inducer, which prevents impeller performance deterioration, and an impeller. Several types of cavitation occur inside the inducer, numerous experiments and CFD simulations are conducted. Though, an inducer takes only small portion of total head of the pump and the following impeller determines whole turbopump performance. In addition, low inlet pressure makes the flow to be cavitated not only at the inducer, but also at the impeller in real cases. Therefore, flow through an inducer and an impeller should considered simultaneously. In this study, LOX pump composed of an inducer and an impeller is analyzed by using commercial CFD code ANSYS CFX 13.0. Non-cavitating flow with high inlet pressure and cavitating flow with low inlet pressure are both simulated and head, suction performances are shown. Evolution of the flow and the cavitation by reducing cavitation number and effect of cavitation on pump performance are studied.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.405-412
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• 2005

Numerical and experimental investigations were conducted to assess the aerodynamic performance of several centrifugal compressors. In order to impose an appropriate physics at the interface between impeller and vaned diffuser numerically, two different techniques, frozen rotor and stage models, were applied and the simulation results were compared with the corresponding prototype test data. An equivalent sand-grain roughness height was utilized in the present computational study to consider a relative surface roughness effect on the stage performance simulated. From a series of investigations, it was found that the stage model is more suitable than the frozen rotor scheme for the steady interactions between impeller and diffuser in turbocompressor applications. It is supposed that the solution by frozen rotor scheme is inclined to overrate the non-uniformity of the flow fields. The predicted aerodynamic performance accounting for surface roughness effect shows favorable agreement with experimental data. Simulations based on the aerodynamically smooth surface assumption tend to overestimate the stage performance.

• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.170-178
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• 1999

In general, an impeller of centrifugal turbomachinery is designed at isolated condition without considering the presence of a volute, but when the impeller is operating with its volute, the performance of impeller can be different. This is largely caused by the interaction between the impeller and volute flow fields. The magnitude of distortion is increased as the operating point is away from the design point and, as a result, the interaction between the impeller and volute is stronger. In the present calculation, the flow through the impeller is simulated using coarse grids. The flow within the impeller and the volute is naturally unsteady, but the flow is assumed to be steady across the interface between the volute and impeller flow fields. Under the assumption of steady three-dimensional incompressible turbulent flow, the time averaged N-S equations involving standard k-$\epsilon$ turbulent model was solved by the F.V.M. The calculation results are compared with the experimental results obtained for an industrial fan by Sakai etc. and the Hood agreement is demonstrated. And the effects of the impeller-volute interaction are studied.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.4
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• pp.225-234
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• 2003

Turbo compressors need high speed rotating impeller in structure, high rate gearbox and conventional induction motor. This mechanical system increased moment of inertia and mechanical friction loss. Recently turbo compressor has adopted a super high-speed motor and driver and have made its size smaller and mechanical friction loss at minimum. In this paper, variable super high - speed motor controller, compressor controller and MMI controller are implemented with only one DSP (TMS320VC33) chip for a 150HP, 70,000rpm direct drive turbo compressor. It was required hardware and software integration. The result of integration, Controller hardware became simple and all control software are developed same developing tool. The implements turbo compressor meets the requirements.