https://scholars.lib.ntu.edu.tw/handle/123456789/61934
Title: | 熔融液滴撞擊壁面之凝固現象探討 The theoretical solidification models of a melt droplet impinging on a cold surface |
Authors: | 邱漢儒 Chiu, Han-Ru |
Keywords: | 液滴撞擊;擴張因子;飛濺參數;最大擴張速度;厚凸參數;spread factor;avioding parameter;droplet impinging;splash criterion;maximun spread velocity | Issue Date: | 2004 | Abstract: | 在此之前,關於無凝固現象之液滴撞擊壁面之擴張因子之預測理論模式,已有先進獲得與實驗頗為相近之預測模式。而當壁面溫度低於液滴凝固點時,於擴張過程中將伴隨凝固之現象。本文即應用能量守恆、質量守恆及流率守恆等原理並植基於等溫壁面,進一步建構伴有凝固現象之擴張因子之理論預測模式。於此為簡化模式,乃僅考慮液滴本身之熱力及物理性質而忽略壁面者。另慮及凝固之發生乃於擴張過程中即伴隨著進行,故引入凝固時間修正因子於擴張因子之預測模式中,以符合實際狀況,並改善預測誤差。除此之外,本文尚試者推導出飛濺參數, ;避免液膜中心厚度凸起之參數, >0.5;及最大徑向擴張速度, 。以上之理論模式分析結果與實驗數據或其他模式相較,誤差約於10%之內。 The predictive theoretical model which investigates the spread factor of a droplet impinging solid surface without solidification had been developed, and had got well agreement with experiments by the previous works[8,10]. In the case that wall temperature is less than the solidification point of droplets,solidification would happen simultaneously. So the present study aims to develop another resemble theoretical model in which considers solidification, based on isothermal surface through the laws of continuity, energy conservation, and flow rate conservation. The developed model mainly focuses on the physical and thermodynamic properties of droplet, ignores that of surface in order to simplify the model. A time correcting factor is introduced into the spread factor model to account for the reality that the solidification of droplet accompanies with spreading,and which may improve its prediction. In addition, several theoretical models are also constructed in the study as follows: splashing criterion ; avoiding parameter for central prominence of splat, >0.5; and maximum spread speed, . The present study has shown a well agreement to experiments or other models within about 10% error analysis. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/61315 | Other Identifiers: | zh-TW |
Appears in Collections: | 機械工程學系 |
File | Description | Size | Format | |
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ntu-93-R91522104-1.pdf | 23.53 kB | Adobe PDF | View/Open |
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