輥輪塗佈製程常因輥輪轉速、輥輪間距及塗料性質的差異而在基材表面形成不均勻的流紋現象，且在一般的塗料中皆含有非牛頓流體的特性，因此要研究如何降低輥輪塗佈的流紋現象必須針對塗料的物理性質及非牛頓流體特性、輥輪轉速比及輥輪間距加以探討。泰勒-庫提流(Taylor-Couette flow)廣泛存在於同軸心圓柱旋轉之電機機械設備內，如車用的旋轉葉片接合器(rotary blade coupling)，則會因散熱不良導致熱應力過高而損毀，因此提升同心圓柱旋轉系統中泰勒-庫提流的熱傳能力，就成為改善此類設備的重要課題。本文主要的目的即是以實驗和數值模擬的方式分析兩轉動圓柱間薄膜流紋的現象，以及探討不同流體性質與操作參數對泰勒-庫提流中的熱液動特性的影響。
在輥輪塗佈中塗料的非牛頓特性是以冪次定理來模擬，冪次項n值的模擬範圍介於0.8 ~ 1.2之間。不同的輥輪間距與轉速比對膜厚與流紋的影響也在本文中詳細討論，輥輪間距與半徑比H0/R的範圍介於3.33×10-4 ~ 6.67×10-4，輥輪轉速比則在1 ~ 4，實驗與數值模擬的誤差在5 ~ 12%之間。由研究結果顯示塗料的膜厚比與非牛頓冪次項、輥輪轉速比及輥輪間距有關：在順輥塗佈時塗料的塗覆輥膜厚(coating film thickness)對進入喉部膜厚(inlet film thickness)比t3/t1與非牛頓冪次項成反比，與輥輪間距對半徑比H0/R和塗覆輥(applicator roll)對帶漆輥(pick-up roll)轉速比V2/V1成正比；而在逆輥塗佈時支撐輥轉印膜厚(transferred film thickness)對進入喉部膜厚(inlet film thickness)比t4/t3則與非牛頓冪次項和輥輪間距對平均半徑比H0/Rm成正比關係，與支撐輥(panel roll)對塗覆輥轉速比V3/V2成反比。流場的壓力峰值會隨著輥輪轉速比和非牛頓冪次項的提高而增加，隨輥輪間距的增加而減少。流紋波長對輥輪間距比λ / H0則與非牛頓冪次項和毛細數(Capillary number)成反比，和輥輪間距成正比。由此可得知當流體的非牛頓冪次項n值和系統的毛細數值愈大，以及輥輪間距愈小時，其所產生的不穩定流紋數量會隨之增加。
至於泰勒-庫提流(Taylor-Couette flow)中兩同心圓柱間的熱液動性能則是以數值方法進行分析，其中包含不同圓柱半徑比(η = 0.6, 0.75, 0.9)、細長比(A = 1, 5, 10, 15, 20)、普蘭特數(Pr = 1, 7, 20, 50, 100)、非牛頓冪次項(n = 0.8~1.2) 和旋轉雷諾數(Reω= 390~3900)對平均紐賽數的影響。由結果顯示平均紐賽數會隨著旋轉雷諾數Reω、普蘭特數Pr以及半徑比η的增加而提昇，而隨著非牛頓冪次項的增加而降低。對細長比而言在細長比A < 10時才有較明顯的影響，當細長比A > 10其對平均紐賽數的影響可忽略。

The ribbing phenomenon and non-uniform film thickness occurred when increasing roll speed and shrinking roll gap in roll coating process, and non-Newtonian property in coating fluid also affected the coating field. It is necessary to analysis the non-Newtonian property of coating fluid, roll speed ratio and roll gap in order to ligten the unstable ribbing. Taylor-Couette flow exists in co-axial rotating electrical equipment such as rotary blade coupling in vehical, and is burned down for high temperature. It is important to improve the thermal behavior in Taylor-Couette flow. In this paper the thermal hydraulic characteristics for thin film ribbing and Taylor-Couette flow between two rotating cylinders were investigated experimentally and numerically.
Non-Newtonian behavior of the roll coating fluid was accounted by using power-law model with power index, n, ranging from 0.8 to 1.2. Effect of roll speed ratio of applicator roll to pick-up roll and gap distance on the coating film thickness and ribbing wavelength were also investigated. The roll gap to radius ratio was within 3.33×10-4 - 6.67×10-4, and the roll speed ratio within 1 - 4. Numerical results were in good agreement with those of experimental data within 5-12%. Results indicated that the film thickness ratios were functions of power-law index, roll speed ratio and ratio of gap distance to roll radius. In forward roll coating process, the coating film thickness to inlet film thickness ratio was reduced as increasing power-law index, and increased as increasing gap to radius ratio and roll speed ratio. In reverse roll coating process, transferred film thickness to inlet film thickness ratio was increased as increasing power-law index and gap to average radius ratio, and decreased as increasing roll speed ratio. The peak pressure in coating flow field was increased as increasing roll speed ratio and power-law index, and reduced as increasing roll gap. The ribbing wavelength-to-gap ratio was reduced as increasing power-law index and capillary number, and enlarged as increasing roll gap. It was shown that the unstable ribbing number was increased as increasing power-law index, capillary number and reducing roll gap.
The thermal-hydraulic characteristics of Taylor-Couette flow in the gap between two horizontal concentric cylinders were investigated. Various radius ratio (η = 0.6, 0.75, 0.9), aspect ratio (A = 1, 5, 10, 15, 20), Prandtl number (Pr = 1, 7, 20, 50, 100), power-law index (n = 0.8-1.2) and rotating Reynolds number (Reω= 390-3900) were evaluated in detail to discuss the effects on Nusselt number. The results indicated that the average Nusselt number of Taylor-Couette flow was increased as increasing rotating Reynolds number, Prandtl number and radius ratio, and decreased as increasing power-law index. The average Nusselt number was affected significantly by aspect ratio A when A≦10, but slightly affected as 10≦A≦20.

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