세라믹공정 PBL 1

세라믹공정 PBL 1

세라믹공정 PBL 1.pptx

목차 Ⅰ. Work 1(Innar diameter) Ⅱ. Work 2(Unknown liquid) Ⅲ. Work 3(Application) 본문 Pressure difference of Curved surface At the constant radius, and for the curved surface, pressure differences can expressed by Laplace equation. For Arbitary radius, pressure differences can expressed by the below equation. Contact angle, θ The contact angle θ is defined as the angle (measured in the liquid) that is formed at the junction of three phases The Young's equation shows the Equilibrium force balance in the three phases. Behavior of Liquids in Capillary This pressure difference due to the curved meniscus must be balanced by the hydrostatic pressure of the liquid column, Experiment(Work 1) Room temperature : 20ºC Density of water : 1000kg / m3 Surface tension of water : 7.28X10-2N/m Contact angle of water on the glass : 22.5º Gravity : 9.81m/s2 R = r / cosΘ For Comparison solution(Water) Observation of a capillary phenomenon Setting temperature : 20ºC in the room Measurement of height of liquid in two capillary tubes (Small tube and Large tube) Calculation of the Surface tension(γ) of liquid Assume that cosΘ ~ 0.9 (Contact angle : 22.5º ~ 30º) Thus, γcosΘ value can give the information about Approximate value of Surface tension(γ) γcosΘ value for the given liquids are computed Assumption and Condition of experiment Room temperature : 20ºC Density of Glycerol : 1261kg/m3 Contact angle of Glycerol on the glass : 24.78º Gravity : 9.81m/s2 Surface tention(γ) of each tubes Surface tension of Glycerol is 63mN/m(Theoretical value) Experimental error for small tube is noticeable! For small tube, the Effect of gravity(g) makes error. Thus, large tube experiment is more correct. 참고문헌 세라믹공정 강의자료 Contact Angles for Liquid Drops at a Model Heterogeneous Surface Consisting of Alternating and Parallel Hydrophobic/Hydrophilic Strips http://www.sciencetimes.co.kr/article.do?atidx=0000039632 http://blog.daum.net/whitebrow09/324 키워드 PBL, 세라믹, 세라믹공정, 공정