• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.123-127
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• 1999

This paper suggests the establishment of high-accuracy and high-efficiency machining method of scroll shape workpiece by using the feed control method. The cutting paths for machining the inside and outside surfaces of the scroll-shape workpiece are calculated, and the calculation method of the cutting chip areas based on the coordinate of the base circle is shown. A feed control method is proposed for a constant cutting area and cutting force. By machining test of scroll shape workpiece, The machined accuracy of wrap, tool wear, and surface roughness are evaluated. By this method, Reduction of the machining time and large increase of the efficiency can be expected.

• 대한기계학회논문집B
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• 제22권11호
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• pp.1635-1646
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• 1998

The present study investigated the effects of geometric parameters considered on the performance of an automotive scroll compressor by assuming ideal, semi-real and real gases for R-134a. The geometric parameters were center thickness of scroll, height of scroll and the size of discharge port. Fourth-order Runge-Kutta method was applied to solve the thermodynamic equations, leaking rate equation and the equation of motion of discharge valve for ideal, semi-real, and real gases. The volumetric and adiabatic efficiencies for semi-real and real gases differed little, but those for ideal gas differed by 18% and 25% compared with those for real gas at 2,000rpm. The volumetric efficiency changed little as the design angle of scroll (${\gamma}$) changed, but the adiabatic efficiency at ${\gamma}$ of $34^{\circ}$ was higher by 2.4% than that of $147^{\circ}$ for 2,000rpm. The volumetric and adiabatic efficiencies at scroll height of 29.8mm were higher by 1.7% and 2.8% than those of 65.8mm. The volumetric efficiency changed little as the size of discharge port changed, but the adiabatic efficiency increased a little as the size of discharge port decreased.

• 한국유체기계학회 논문집
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• 제19권6호
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• pp.50-54
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• 2016

The performance of a scroll expander is the most important factor for the efficiency of small scale Organic Rankine cycle waste heat power generation systems. In this research, a scroll compressor was purchased and operated in reverse to function as a scroll expander. With air as a working fluid, a series of performance test were conducted on this expander by varying the inlet and outlet pressure. Secondly, We have tested through 2000 to 3500 rpm rotational speed to find the maximum power and efficiency of the expander. And last, It was observed in the initial experiments that the design of the expander's orbiting scroll wrap partially blocked the fluid intake which may have caused unnecessary flow resistance. To verify this theory, a small part of the scroll wrap was removed and the performance test was redone. It was observed that the lower back pressure assure the higher efficiency and power of expander and the rotational speed that shows maximum adiabetic efficiency of scroll expander is 69% at 2500 rpm. And by modified wrap of the scroll, we could get volume flow rate for 13% to 19% and power for 5% to 18% increased. But the maximum efficiency of the modified scroll was decreased 8%.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1139-1147
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• 2000

This paper describes that the size of inactive zone can be directly applied to design multiblade fan/scroll system. From the experimental studies using a five hole pitot tube and smoke test, it is found that the size of inactive zone has linear relations with the mean velocity of impeller inlet and cut-off angle gives a great influences to the fan efficiency. For the practical design, a function related with geometric parameters(i.e. inner radius, cord length, cut-off clearance and cut-off angle) of fan/scroll system is suggested. By using these formulas, the size and distribution of inactive zone can be predicted without the measurements through the full domain, it can be possible to use them to know the efficiency improvement for new model designed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.840-844
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• 2003

A study for increase of fan flow rate by geometric modification has been conducted to decrease temperature rise of marine generator inner part. Through experiment of a real product, a performance curve for various flow resistances was obtained. Flow analyses for each cases were done by using commercial code-FLUENT and the results were very similar to experimental data (0.7% deviation at normal operating condition). Through flow analysis results for various design geometric modification, a scroll type fan was adopted as a best design geometry with 100Pa more pressure and 22% more flow rate than original fan.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.153-153
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• 2014

건식 진공펌프(dry vacuum pump)는 기계적 저진공펌프 중 펌프 내부의 기체 배기통로에 오일을 전혀 사용하지 않는 펌프의 통칭으로써, 대개 비접촉형으로 여러 형태의 회전자가 고속으로 회전하면서 흡기구로부터 들어온 기체를 압축해 배기를 한다. 비접촉형에는 루츠(roots)형, 클로(claw)형, 스크류(screw)형, 스크롤(scroll)형 등이 있다. 그 중 스크류형 펌프는 큰 배기속도를 갖는 펌프의 설계에 유리하고 높은 운용온도가 가능하여 다수공정에 쉽게 적용할 수 있는 장점이 있다. 그러나 1단 펌프 구성을 갖게 됨에 따라 루츠형 대비 높은 소비전력 특성을 보이는 약점을 가지고 있다. 본 논문에서는 건식 진공펌프 중의 하나인 스크류형 진공펌프에 대하여, 기본적인 1단 펌프 구성에 스크류 리드(lead)의 변화를 주어 기존의 똑같은 리드의 스크류 진공펌프에 대한 소비전력 및 배기구 온도 등 스크류 형상에 대한 성능평가 연구를 진행 하고자 한다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.70-77
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• 2004

Comprehensive investigation on the outlet's geometric shapes of a centrifugal blower with higher inlet resistance than an atmospheric pressure is carried out for improvements of its performance. Most unwanted behaviors of such blower are pulsating flows because of unbalance between inflows and outflows in a scroll casing. In order to reduce this undesirable phenomenon a triump is made for both the shape of outlet duct and an accessory structure inserted in the outlet port of the blower. The modification on the shape is concerned with the contraction of cross sectional area and the attached structure is for an intentional obstruction to cause a flow resistance. The details of the modification are examined for different cases and results. The methodologies for the work are performance evaluations including noise level and velocity measurements with PIV Consequently, the performance of improved system is close to that of the system operating with atmospheric pressure at the inlet.

• 대한기계학회논문집B
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• 제26권10호
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• pp.1341-1347
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• 2002

In order to improve efficiency of a system with three-dimensional flow characteristics, this paper presents a new method that overcomes three-dimensional effects by using two-dimensional CFD and neural network. The method was applied to shape optimization of cut-off in a multi-blade fan/scroll system. As the entrance conditions of two-dimensional CFD, the experimental values at the positions out of the inactive zone were used. The distributions of velocity and pressure obtained by two-dimensional CFD were compared with those of three-dimensional CFD and experimental results. It was found that the distributions of velocity and pressure have qualitative similarity. The results of two-dimensional CFD were used for teaming as target values of neural network. The optimal angle and radius of cut-off were determined as 71$^{\circ}$and 0.092 times the outer diameter of impeller, respectively. It is quantified in the previous report that the optimal angle and radius of cut-off are approximately 72$^{\circ}$and 0.08 times the outer diameter of impeller, respectively.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.225-231
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• 2003

In order to improve efficiency of a system with three-dimensional flow characteristics, this paper presents a new method that overcomes three-dimensional effects by using two-dimensional CFD and response surface method. The method was applied to shape optimization of cut-off in a multi-blade fan/scroll system. As the entrance conditions of two-dimensional CFD, the experimental values at the positions out of the inactive zone were used. In order to examine the validity of the two-dimensional CFD the distributions of velocity and pressure obtained by two-dimensional CFD were compared with those of three-dimensional CFD and experimental results. It was found that the distributions of velocity and pressure show qualitatively similarity. The results of two-dimensional CFD were used for constructing the objective function with design variables using response surface method. The optimal angle and radius of cut-off were determined as $72.4^{\circ}$ and 0.092 times the outer diameter of impeller, respectively. It is quantified the previous report that the optimal angle and radius of cut-off are approximately $72^{\circ}$ and 0.08 times the outer diameter of impeller, respectively.

• 한국음향학회지
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• 제40권6호
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• pp.555-565
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• 2021

본 연구의 목표는 냉장고 냉동실 냉기순환용으로 사용되는 후향익 원심팬 시스템을 대상으로 익형의 형상을 최적설계 하여 유동성능 및 소음성능을 향상시키는 것이다. 대상 시스템은 전형적인 원심팬 시스템에서 사용되는 스크롤 하우징 형상 없이 두 개의 Volute가 후면 덕트 시스템과 연계하여 냉기를 공급한다는 특성을 가지고 있다. 먼저 팬 시스템의 유동 및 소음성능을 실험적으로 평가하였다. 유동실험에서 팬 성능 시험기를 사용하여 P-Q 곡선을 도출할 수 있었으며, 무향실에서 소음실험을 통해 소음 스펙트럼을 측정하였다. 다음으로, 3차원 비정상 Navier-Stokes 방정식을 전산유체역학을 사용하여 수치해석하여 유동 특성을 분석하였으며, 예측한 유동장을 입력값으로 Ffowcs Willams-Hawkings방정식을 이용해 소음해석을 수행하였다. 수치해석결과는 실험 결과와 비교를 통해 그 유효성을 검증하였다. 검증된 수치해석 기법을 기반으로 반응표면법의 2인자 중심합성법을 통해 유량이 최대가 되는 입구각 및 출구각을 도출하였다. 마지막으로 최적화된 팬을 대상으로 시제품을 제작하여 실험한 결과 개선된 유량 성능 및 소음성능을 확인하였다.