太陽能轉子的模擬分析與實驗之研究

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/76773

Title:	太陽能轉子的模擬分析與實驗之研究
Authors:	黃宣翰;HUANG, HSUAN-HAN
Contributors:	生物物理研究所
Keywords:	太陽能轉子;表面張力;數值模擬;solar rotor;surface tension;numerical simulation
Date:	2018-08-15
Issue Date:	2018-08-31 11:40:30 (UTC+8)
Publisher:	國立中央大學
Abstract:	在本研究中太陽能轉子已排除先前製程的差錯，而得以直接照射陽光即可運轉。這不僅意味著更有效的能源轉換，亦將有助於對太陽能轉子的普及化及各種變因的研究。本論文共分為兩個方面的研究，模擬部份與實驗部份。電腦模擬的部份，使用有限元素分析，理論模擬轉子實際的實驗環境對於轉子轉動的影響；實驗研究部份，使用了太陽光和強力手電筒做為實驗的光源。其中先以前者驗證轉子可在不使用凸透鏡聚光的狀況下也能直接照射日光而使轉子運轉，再針對各種變因進行探討。使用的變數包含輻照度、水深、銅箔接觸寬度、轉子大小、水溫等。在改變輻照度的研究中，我們發現輻照度越高，轉子的轉速也就越快。在水深的研究中，我們發現容器大小不同會有不同的結果，並推測原因是照射至小容器(250ml燒杯)杯壁的光會有反射的現象，因而造成水深淺的位置有較高的輻照度與轉速。在水溫方面我們發現水的溫度越低，轉子的轉速就越快。其原因是水溫越高會與被太陽光加熱後的銅箔的溫度溫差越小，造成轉速變慢的情形。在改變轉子大小的研究中，我們發現提升轉子面積大小而增加吸光的量與增加的阻力相比，後者對於轉子轉速的影響更大，也就是說若只考慮轉速，把轉子縮小是較可行的，但是若考慮能量轉換效率值反而轉子越大越好。在改變轉子銅箔接觸寬度的研究中，我們發現在每個大小轉子可能都有其適合的接觸寬度，並不如模擬所得越大越好。在銅箔的厚度方面我們並沒有模擬，但我們從實驗中明確的得出，銅箔厚度越厚，導熱的效果也就越好，因而造成轉子轉速更快。在水域大小的研究中，在水域大小接近於轉子面積的的條件下，會使轉子變慢，其原因是因為邊界的黏滯力，而當水域大到一定程度時，轉子的轉速將不再變動，這些觀察與模擬結果一致。 ;In this study, the improved “solar rotors” can be operated with "direct sunlight" by manufacturing without previous mistakes. This advancement implies a more effective conversion of energy, and will facilitate their popularization. The approach in this thesis is two-folded: simulation and experiment. In the part of computer simulation, the finite element analysis is used to simulate the effects of actual experimental environment on the rotation of rotors. In the experimental part, the sunlight and a high-power electrical torch are used as the light source. The former is used to verify that the “solar rotor” can be operated without using a convex lens, followed by the latter to study the dependence of the rotors’ speed upon various parameters. It is found that a higher light intensity results in a faster rotor as expected. However, the depth of water affects the rotation in different ways depending on the size of the container. In the case of a small container such as a beaker, a lower water level results in a faster rotation, which is contradict to the simulated result. This surprising result is attributed to a possible focusing effect by reflection of light from the beaker’s wall. On the other hand, hotter water is found to slow down the rotors due to a reduced temperature difference between water and the copper foil. As for the size effect of the rotors, our data reveal that a larger rotor has a slower rotation (which implies a great effect of viscous resistance over that of light absorption) but a higher efficiency of energy conversion. Also, there appears to be an optimized contact width of copper foil with water for each rotor size, unlike the result of simulation that predicts a faster rotor corresponds to a larger contact width. As for the effect of the foil’s thickness, it is found that a thicker copper foil results in a faster rotor, which can be attributed to a greater effective thermal conductance. Finally, the rotation will be slowed down when the area of water surface is reduced, which is presumably caused by the viscous force of water between the rotor and the wall of container. However, a maximum speed of rotation will be reached as the area of water surface is increased. Both of these observations are consistent with the results of simulation.
Appears in Collections:	[Graduate Institute of Biophysics] Electronic Thesis & Dissertation

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