• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.70-75
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• 2006

The performance of a turbopump system composed of an inducer, an impeller, a volute and seals has been computationally analyzed. To save the computational time, only one flow passage of the inducer and impeller is considered for the computations. A steady mixing-plane method is used on the impeller/volute interface for simulating the unsteady interaction phenomena. The axial thrust is predicted from the turbopump calculation in its entirety, which is necessary for such estimation. Moreover, the effects of each component on the pump performance are investigated at a design condition through the analysis of flow structures. The predicted performance is in good agreement with experimental data in terms of head rise, efficiency and volute wall pressure distributions despite of highly complex flow structures being present. The computational results also show that the axial and radial thrusts are within the design limit although corresponding experimental measurements were not taken.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.317-320
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• 2011

Hydrogen peroxide turbopump was designed for bi-propellant liquid rocket engine using hydrogen peroxide and kerosene as propellants. Turbopump operation was verified through water tests. Design conditions of hydrogen peroxide turbopump were determined, and impeller was designed. Turbine which drives pump was selected from commercial turbocharger. Gas generator was designed by reference from turbine map. Pump, turbine, gas generator were integrated, and turbopump system was constructed. Turbopump supplied water by 1.47 bar of pressure and as well as 3.4 kg/s of mass flow rate.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.205-210
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• 2007

A LOX pump rotordynamic design was performed for a 75 ton thrust liquid rocket engine. Axial positions of an inducer, an impeller and bearings on a shaft are decided on the basis of the experience achieved by previously developed turbopump which has the similar layout. The result of pump hydraulic design was reflected in the present study to decide axial length of the inducer and impeller. A distance from the rear bearing to the impeller was considered as a design parameter for load distribution of the bearings. Asynchronous eigenvalue analysis was performed as a function of rotating speeds and bearing stiffness to investigate critical speed of the LOX pump. From the numerical analysis, it is found that the LOX pump with the proper bearing loads safely operates as a sub-critical rotor of which critical speed is high enough compared to the operating speed 11,000 rpm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.9
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• pp.1-10
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• 2006

An optimization study on a small turbopump impeller operating at the low specific speed is conducted to obtain high output head at the impeller exit. Its specific speed in SI unit (RPM, m3/sec, m) is 4.0, and the outer diameter is 56mm. On the optimization, the outer diameter of the impeller is maintained constant to restrict the pump size, and an objective function of pressure head is maximized with eight design variables, which are related with designing an impeller shape. The response surface method is used to the optimization scheme, and the commercial code CFX-10 is applied for numerical analysis. The pressure head of the objective function obtained with an optimized impeller is increased by 9.7% compared with that obtained on an impeller designed with typically recommended design parameters. This increment is caused by reducing the recirculation region within the impeller passage.

• 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.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.72-80
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• 2004

LOX pump is one of the sub-assemblies constructing turbopump unit. In the current study, static structural analysis on such rotating parts as impeller and inducer has been carried out. Three major factors which can affect the structural stability of the rotating parts of LOX pump, are temperature, pressure, and centrifugal force. The effect of each factor was preliminarily investigated, then the analysis under the consideration of the combined loading conditions has been carried out. The major factor that affects the structural stability was proved to be temperature. The analyses of the combined cases showed that the designed impeller and inducer had reasonable safety margins, which means that the impeller and the inducer will be stable in static structural strength. Although there was no problem in the structural strength of the impeller and the inducer, a model analysis should be followed in order to verify the interference between the rotating part and the inner surface of casing.

• 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.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.183-190
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• 2004

The performance analysis of a fuel pump for a liquid rocket engine has been performed numerically on its design condition. A commercial three-dimensional Navier-Stokes flow solver has been used for the computation. All of the fuel pump components - inducer, impeller, volute and secondary flow passages - are included in computation for the accurate estimation of the leakage flow rate which affects the performance and axial thrust. A pitchwise-averaged mixing plane method was used on the boundaries among the fuel pump components to save computational time. The predicted overall performance satisfied the design requirement. However, the axial thrust exceeded a permissible limit. In order to reduce the axial thrust, the secondary flow passage design has been changed. With this change, the axial thrust level has been reduced to 30% as compared with the original value.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.8-13
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• 2010

An effective control of the axial thrust of a turbopump is one of the critical issues for obtaining its operational stability. Axial thrusts of the fuel pump for the 75-ton class rocket engine under development were measured with water as a test propellant at a room temperature. According to the test results, the axial thrust of the fuel pump seemed to satisfy the axial force condition of its bearing. Also, the thrust was increased as a whole when the flowrate of the pump was decreased. Furthermore it was found that the thrust and the leakage flowate were modified when the gaps between the floating ring seals and the impeller were changed.

• 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.