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목분 충진 고분자 용융체의 압출다이 내 유동 및 열전달에 관한 수치해석
고승환(Seung Hwan Ko),박형규(Hyung Gyu Park),송명호(Myungho Song),김찬중(Cham-Jung Kim) 대한기계학회 2001 대한기계학회 춘추학술대회 Vol.2001 No.9
A three-dimensional numerical analysis of the flow and heat transfer characteristic of wood-flour-filled polypropylene melt in an extrusion die was carried out. Used for this analysis were Finite Concept Method based on FVM, unstructured grid and non-Newtonian fluid viscosity model. Temperature and flow fields are closely coupled through temperature dependent viscosity and viscous dissipation. With large Peclet, Nahme, Brinkman numbers, viscous heating caused high temperature belt near die housing. Changing taper plate thickness and examining some predefined parameters at die exit investigated the effect of taper plate on velocity and temperature uniformities. In the presence of taper plate, uniformity at die exit could be improved and there existed an optimum thickness to maximize it.
접촉전도와 반투명 복사가 반도체 웨이퍼의 CVD 공정 중 열전달에 미치는 영향
윤용석(Yong Seok Yoon),홍혜정(Hye Jung Hong),송명호(Myungho Song) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.2
During CVD process of semiconductor wafer fabrication, maintaining the uniformity of temperature distribution at wafer top surface is one of the key factors affecting the quality of final products. Effect of contact conductance between wafer and hot plate on predicted temperature of wafer was investigated. The validity of opaque wafer assumption was also examined by comparing the predicted results with Discrete Ordinate solutions accounting for semitransparent radiative characteristics of silicon. As the contact conductance increases predicted wafer temperature increases and the differences between maximum and minimum temperatures within wafer and between wafer and hot plate top surface temperatures decrease. The opaque assumption always overpredicted the wafer temperature compared to semitransparent calculation. The influences of surrounding reactor inner wall temperature and hot plate configuration are then discussed.
김문수,송명호 동국대학교 산업기술연구원 2000 산업기술논문집 Vol.11 No.2
An experimental study on the extrusion process of paraffin has been conducted as a step to understand the relations between extrusion parameters and the productivity of polypropylene wood flour composite extrusion process. The emphasis was made on the influence of extrusion pressure, temperature and cooling conditions upon phase change characteristics and the occurrences of extrusion defects. The polypropylene wood flour composite is a promising material with a number of applications in construction, furniture, machinery parts and etc., as it combines the excellent texture of natural wood and the continuous manufacturing potence of plastics. Besides, it is near waterproof and soundproof, is made with wood waste and recycled plastics, and thus, environment friendly. Paraffin was used as an analogy material for polypropylene since it is a thermoplastic polymer, has a lower phase change temperature, and is transparent in liquid state, which enables the flow visualization by shadowgraph diagnostics. The extrusion speed and the cooling conditions as well as the temperature of paraffin melt at the entrance of the cooling section were varied, while the pressure of the melt and the temperature distribution along the cooling surface were measured as the experimental results. When the cooling is not sufficient or the extrusion speed is too large the melt rupture occurred through the gap between the solidified paraffin and the cooling surface. Precautions needed for the design of extrusion apparatus are described.
알루미늄 薄膜과 合成樹脂 多隔室 構造로 이루어진 板形 素材의 斷熱 特性
이온구,이동진,안정혁,송명호 동국대학교 산업기술환경대학원 1998 산업기술논총 Vol.4 No.-
An experimental and theoretical study on heat transfer characteristics of a polymer bubble film sandwiched between two aluminium foils has been conducted in order to obtain better understanding required for improved design of reflective insulation materials. Mathematical models, accounting for diffusive, convective and radiative mode of energy transfer and utilizing equivalent thermal resistance circuit, were set up. The predicted value of effective heat transfer coefficient served as reference for the measured effective thermal conductivities. The effective thermal conductivities of the specimen were also experimentally determined from the measured values of temperature difference and heat generation rate utilizing guarded hot box method for different orientations of specimen relative to the gravity direction and for different temperatures. The predicted and measured results showed good agreements and revealed that insulation decreases as the temperature difference increases when the imposed temperature gradient is either horizontal or downward. The smaller bubble size then those of present specimen is desirable for better insulation performance.