• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.86-90
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• 1992

스크류 압축기는 진동이 작고 맥동이 적으며, 소형이고 고효율이라는 특징이 있다. 또한 식품, 화학, 전자공업 등에서 무윤활식 압축기로 사용되어지고 있다. 본 연구에서는 호프로 자른 것과 같은 다각형 오차를 만들지 않고 매끄러운 면을 얻을 수 있는 스크류 로터의 축직각 단면좌표를 이용한 cutter의 형상을 설계하는 것을 목적으로 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.711-717
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• 2017

Measurements of the moment of inertia of a small turbocharger rotor were studied. A measuring device was manufactured using the trifilar method and the moment of inertia of the calibration rotor was measured to verify the device. The coefficient of variation was 0.43% and the error was 0.75%. The results showed that the device is suitable for measuring the moment of inertia of a turbocharger rotor. Next, the moment of inertia for two turbine rotors and compressor wheels was measured. Those for the turbine rotors showed precise and accurate results in that the coefficients were under 1.0% and the errors were under 3.0%. On the other hand, those for the compressor wheel were precise but inaccurate in that the coefficients were under 1.0% and the errors were over 24.4%. Therefore an indirect method for the compressor wheel was suggested. The results showed that the coefficients were under 1.2% and the errors were under 7.88%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.137-138
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• 2012

본 연구에서는 가스터빈 압축기 로터용 제작 관통볼트의 건전성 검사가 수행됐다. 육안검사, 치수, 재질, 경도 및 피닝처리 등을 검사했으며 GE 볼트와 비교해 건전성을 판단하였다. 평가 결과 제작볼트는 기준범위 이하의 피닝강도로 처리되었다. 이에 숏피닝 강도를 향상시켜 다시 제작된 수정볼트를 재검사했고 모든 항목에서 기준범위에 포함됨을 확인했다. 궁극적으로 본 연구에서 수행된 가스터빈 압축기 로터용 관통볼트의 건전성 검사가 유효함을 확인하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.627-631
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• 1993

스크류 압축기는 진동이 적고, 소형이면서 고효율을 유지하기가 용이하다는 특징을 가지고 있으며, 원통형 밀패용기 내에 암,수로터가 서로 반대 방향으로 맞물려 회전하면서, 로터홈과 케이싱 사이에 생기는 공간의 용적이 로터회전에 의해서 가스를 흡입, 압축, 배출하는 합축기 이다. 본 연구는 로터의 치형 함수의 기하학적성질 및 제한사항을 고려하여, 대칭 치형을 치수의 조합과, 원, 점, 직선, 타원을 사용하여 비대칭 치형을 설계하였다. 본 연구의 목적은 설계된 치형과 기존의 치형을 치형 형상의 변화에 따른 특성값 (실라인길이, 누설삼각형, 용적곡선, 흡입 및 토출 홈면적)의 변화에 대하여 연구함으로서 성능검토를 시도하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.184-193
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• 2002

This study aims at the optimal design of the screw rotor and its performance analysis. The optimal design of the screw rotor's shape has been performed theoretically. Also, the performance analysis technique of an oil-injected screw air compressor is developed. The effect of internal leakage, heat exchange between air and oil, and flow resistance at suction and discharge ports are included in the performance analysis. Some numerical examples of the volumetric efficiency and adiabatic efficiency for sample rotors are demonstrated for various lobe combination, rotor wrap angles and L/D ratios.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1285-1288
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• 2005

Screw rotors, the key parts of screw compressors, are used in compressing air and refrigerant due to their high productivity, compact size, low noise and maintenance. In general, a screw compressor is composed of a pair of rotors of complex geometric shape. The manufacturing cost of the screw rotors is high because the complicated helical shapes of the screw rotors are manufactured usually by the dedicated machine tools. In this study, rotor profile is divided into three parts for the efficient machining. The formed tools are designed and shared for the respective split region. By cutting the screw rotor using the formed tools, this method is more efficient than the end mill in machining rotor. Experimental results show that 4-axis machining using formed tools needs less time and has the accuracy.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.3
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• pp.75-80
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• 2007

It is necessary to analyze the contact phenomena in order to effectively design the machine components with contact surfaces. In general, the contact action is highly nonlinear and irreversible because we cannot predict the contact regions and conditions. Recently, the finite element method is used to analyze the contact problem. In this paper, the contact element method is applied to avoid the mesh refinement and iterative calculation of general contact algorithms. By use of it, the deformation and stress concentration of turbo compressor rotor are computed. It shown that the contact element is convenient analysis and the results are relatively accurate.

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.30-36
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• 2018

In this study, a small-scaled test system for a tip jet rotor was developed to contribute to the research on unmanned compound rotorcraft. The performance and dynamic characteristics of the tip jet rotor were investigated using the test system. The diameter of the tip jet rotor was set to 2m in consideration of the size of the test site and the pneumatic supply capacity of the. The rotating speed of the rotor was controlled by the pressure of the compressed air. The thrust and forces during the rotor rotation were measured using a load measuring device. A hydraulic actuator was installed for the dynamic test and full-bridge strain gages were attached to the root of each blade to measure the flap, lag, and torsion-wise responses generated when the rotor is excited by the actuator. The performance and dynamic characteristic tests were conducted at various rotor speeds and blade pitches. In order to check the validity of the test results, the results were also compared with the CAMRAD II analysis.

• Tribology and Lubricants
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• v.29 no.6
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• pp.386-391
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• 2013

Part I of this study analyzed the effects of tilting pad bearing designs to reduce the stiffness of the bearings used in a process high-speed lightweight centrifugal compressor intended for a domestic refinery use. This was done in an attempt to enhance the robustness of its rotordynamic stability against possible aerodynamic cross-coupled stiffness. The bearing design variables reviewed were the clearances, LBPs, LOPs, and preloads. The results showed that there was practically no difference between the LBP and LOP designs in terms of the bearing stiffness, because the compressor rotor was lightweight and the bearings had relatively high preloads. Increasing both the machined and assembled clearances in bearing designs has resulted in the bearing stiffness being greatly reduced. In addition, it has been confirmed that an additional reduction in the bearing stiffness can be obtained for given fixed machined clearances by decreasing the preloads, i.e., by increasing the assembled clearances.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1026-1034
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• 2002

This paper describes the development of machining simulation program which is able to design cutter profile and 3-dimensional geometry for rotors in screw compressor. Based on the symmetric rotor profiles developed previously, cutters are designed and 3-dimensional geometries of rotors are generated by using simulation program. Symmetric rotors are manufactured by a universal milling machine, and surface geometries of them are measured by a 3-dimension scanner It is shown that simulation program developed is useful to design cutter for rotor manufacturing and to generate the 3-dimensional helicoid geometry of rotor in screw compressor.