• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.63-69
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• 2022

Compressor efficiency must be improved to reduce refrigerator power consumption. In this study, the heat dissipation rate through the compressor housing is increased via gap flow passages between the compressor body and housing. Four types of gap flow passages are considered for achieving the maximum heat-dissipation rate. In addition, thermal analysis is performed to examine the effect of increased heat dissipation rate on the energy efficiency ratio (EER). The results show that the heat dissipation rate, compressor superheat, and compressor EER increased by up to approximately 52%, 3 ℃, and approximately 1%, respectively.

• Transactions of Materials Processing
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• v.9 no.4
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• pp.413-420
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• 2000

In the die casting process, the flow of liquid metal has significant influence on the quality of casting products and die life. For the optimal process design of front housing part of aircon compressor, various analyses were performed in this study by using computer simulation code, MAGMAsoft. The simulation has been focused on the molten metal behaviors during the filling and solidification stages for the sound casting products. Two cases of casting design that have different types of gating system are considered in the analysis. The potential sites where the casting defects may occur is examined by computer simulation and an improved design process is proposed. Also the effect of partial squeeze on the quality of casting products is considered and the optimal time lag after filling process is determined. For the die-stability, the effect of operational parameters such as die temperature, heat cycle and spot cooling on the die life has also been analyzed.

• Transactions of Materials Processing
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• v.21 no.3
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• pp.195-201
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• 2012

A vacuum ladling die casting system is suggested as a means to obtain a high vacuum level. A high vacuum of 17.8 mmHg is obtained by sealing the inner space of the mould. The sample product is a rear-head housing for an auto-compressor, and the die-casting with 6-cavities was conducted. The flow analysis shows that the filling speed during vacuum ladling is faster than for a non-vacuum system. The air holes in the sample product were too small to be seen with the naked eye in X-ray films. Density tests show that the high vacuum ladling system reduces the internal porosity as much as 57.8% when compared to the non-vacuum system. A defective rate of only 0.17% was found from leak testing. The results of this research prove that the high vacuum die-casting process is useful for manufacturing of aluminium components under high internal pressure.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.242-247
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• 2000

In this study, the Rayleigh's energy method and the Rayleigh-Ritz method on the basis of Flugge's shell theory was used to analyze the dynamic characteristics of the scroll compressor housing with clamped boundary condition. The frequencies and mode shapes from theoretical calculation were compared with those of commercial finite element code, ANSYS. In order to validate the theory, modal test was also performed by impact test and FFT analysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.977-980
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• 2011

In this paper, explain to development of low pressure axial compressor performance test rig in KARI. Performance test rig consist of a entrance section, rotor, stator, shaft, rig housing, bearing housing and exit section. Test rig design structural optimization to rotor dynamics analysis of the simplified rotor-shaft assembly and flow analysis of entrance/exit section.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.4
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• pp.351-358
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• 2006

This paper presents analytical results of a rotary vane compressor performance when the compressor is used for air supply from underwater. Compression characteristics such as pressure and temperature in a compression chamber are analyzed. Volumetric and adiabatic efficiencies are calculated. Vane dynamics are also performed to give reaction forces on the vane from the cylinder inner surface and from vane slots. Compressor efficiency is about 34.9%, and about 55% of the compressor loss is produced by the friction between the vane nose and the cylinder wall. Volumetric efficiency is about 79.5%, and indicated efficiency is about 77.1%, which are comparable to other displacement type compressors. When roller was introduced between housing inner wall and vane tips, mechanical efficiency could be improved by as much as 24.9%, depending on the roller friction.

• The KSFM Journal of Fluid Machinery
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• v.18 no.3
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• pp.12-19
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• 2015

As a means of improving cycle performance of a R410A air-conditioning system, a combined structure of compressor and expander was introduced. A vane rotary type expander was designed to share a common shaft with twin type rolling piston rotary compressor in a housing. Numerical simulation on the performance of the combined compressor and expander was carried out. At ARI condition, the volumetric and total efficiencies of the designed vane expander were 69.37% and 30.23%, respectively. With the application of this expander, the compressor input was reduced by 3.91%, and the cooling capacity was increased by 3.98%. As a result, COP of the air-conditioning system was improved by 8.2%. As the pressure difference between the condenser and the evaporator becomes large, COP improvement increases unless the mass flow rate in the expander exceeds that in the compressor.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.98-107
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• 2009

Vibration analysis of a turbo compressor test rig was carried out in order to investigate the vibrational characteristics of the compressor facility in KARI before conducting the compressor performance test of 5MW-class gas turbine engine for generation. The overall compressor test facility consists largely of inlet and exit ducts, a test section and a driving part. Vibration was measured with accelerometers at the test section and the driving part, especially at a main housing, a collector, a bearing carrier, a torquemeter, a gearbox, and an electric motor. Gap sensors are also installed to measure the rotordynamic characteristics of compressor shaft.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.3
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• pp.107-115
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• 2018

A design combining the use of a compressor and expander was introduced in order to improve the cycle performance of a $CO_2$ automotive air conditioning system. Both the compressor and expander used were of rotary vane type and were designed to share a common shaft in a housing. Numerical simulation was carried out to evaluate the merit of the combined unit. In a typical automotive air conditioning operating conditions, the COP of the system was improved by 8.7% by the application of the combined unit. The compressor input was reduced by 5.2% through use of the expander output. In addition, about 3.06% increase in the cooling capacity was obtained through isentropic expansion in the expander. Our study noted that, as the pressure difference between the gas cooler and the evaporator becomes larger, the COP of the system improved increases unless the mass flow rate in the expander exceeds that in the compressor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.709-712
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• 2003

Recently, high noise problem was experienced during the development of 2-pole squirrel cage motor for industrial compressor. In order to firstly identify the noise characteristics, a variety of measurements were carried out. It was found out that high noise was dominated by linear and nonlinear slot noise components. For the development of low noise indusrial motor, the air gap between rotor and stator in the motor was firstly enlarged. Secondly, it was also modified for the cooling housing to have high absorption features. Consequencely, low noise 2-pole motor having the noise level of less 80㏈(A) was developed. In this paper, a series of noise identification and control process for this motor are introduced.