• The KSFM Journal of Fluid Machinery
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• v.2 no.1 s.2
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• pp.108-113
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• 1999

In a scroll compressor it is generally accepted that a check valve is necessary to prevent reverse rotation of the scrolls. The check valve is subjected to discharge pulsations and their resultant forces. The flow phenomena around the check valve may affect the efficiency and the noise level significantly. The motivation of this study is to understand the flow phenomena and the unstable motion of the check valve on operating conditions in order to identify reasons raising noise and improve the performance of the check valve. In this study, unsteady flow simulation was performed using CFD and the pressure distribution around the check valve was obtained. This paper also shows that unstable motion of the check valve on standard operating conditions through theoretical analysis and flow visualization.

• Economic and Environmental Geology
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• v.41 no.3
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• pp.299-314
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• 2008

The NE-trending Honam shear zone is a broad, dextral strike-slip fault zone between the southern margin of the Okcheon Belt and the Precambrian Yeongnam Massif in South Korea and is parallel to the trend of Sinian deformation that is conspicuous in Far East Asia. In this paper, we report geochemical and isotopic(Sr and Nd) data of mylonitic quartz-muscovite Precambrian gneisses and surrounding foliated hornblende-biotite granitoids near the Myeongho area in the Yecheon Shear Zone, a representative segment of the Honam Shear Zone. Foliated hornblende-biotite granitoids commonly plot in the granodiorite field($SiO_2=61.9-67.1\;wt%$ and $Na_2O+K_2O=5.21-6.99\;wt%$) on $SiO_2$ vs. $Na_2O+K_2O$ discrimination diagram, whereas quartz-muscovite Precambrian orthogneisses plot in the granite field. The foliated hornblende-biotite granitoids are mostly calcic and calc-alkalic and are dominantly magnesian in a modified alkali-lime index(MALI) and Fe# [$=FeO_{total}(FeO_{total}+MgO)$] versus $SiO_2$ diagrams, which correspond with geochemical characteristics of Cordilleran Mesozoic batholiths. The foliated hornblende-biotite granitoids have molar ratios of $Al_2O_3/(CaO+Na_2O+K_2O)$ ranging from 0.89 to 1.10 and are metaluminous to weakly peraluminous, indicating I type. In contrast, Paleoproterozoic orthogneisses have peraluminous compositions, with molar ratios of $Al_2O_3/(CaO+Na_2O+K_2O)$ ranging from 1.11 to 1.22. On trace element spider diagrams normalized to the primitive mantle, the large ion lithophile element(LILE) enrichments(Rb, Ba, Th and U) and negative Ta-Nb-P-Ti anomalies of foliated hornblende-biotite granitoids and mylonitized quartz-muscovite gneisses in the Yecheon Shear Zone are features common to subduction-related granitoids and are also found in granitoids from a crustal source derived from the arc crust of active continental margin. ${\varepsilon}_{Nd}(T)$ and initial Sr-ratio ratios of foliated hornblende-biotite granitoids with suggest the involvement of upper crust-derived melts in granitoid petrogenesis. Foliated hornblende-biotite granitoids in the study area, together with the Yeongju Batholith, show not changing contents of specific elements(Ti, P, Zr, V and Y) from shear zone to the area near the shear zone. These results suggest that no volume changes and geochemical alterations in fluid-rich foliated hornblende-biotite granitoids may occur during deformation, which mass transfer by fluid flow into the shear zone is equal to the mass transfer out of the shear zone.