| Abstract: | 大自然界中有許多物質都以粉顆粒體形式存在，例如砂礫、石頭、穀粒等。在日常生活中，食品業、化學工業、製藥業、冶金礦物業原料也屬於顆粒形狀。只要運用來儲存粉顆粒體形狀原料的行業，都會運用到儲槽。因此儲槽在工業界中是一個非常普遍的應用，主要在管理儲存粉顆粒材料，並且控制顆粒的排放流率。就尺寸而言，大至如穀類、飼料與水泥等儲倉，小至如計時沙漏；就使用方式，可區分為長期與短期儲放、需反覆存入與排出或需填裝入容器等。因此由前述可知儲倉的應用非常普遍，但因規模尺寸越做越大，且儲槽內部狀況不易觀察、監測與儲倉排放控制的技術門檻也大幅提高。本計畫將針對顆粒於儲槽內之排放流動與熱傳行為進行為期三年的研究。第一年度計畫將針對微小粉顆粒在儲槽內之排放行為進行探討與分析。由於微小粉末的內聚力相對大尺寸粉顆粒之內聚力來的大，加上儲槽排放過程是一個二相流的系統，故間隙氣體的影響也相當重要，甚至有時間隙氣體會群聚於儲槽內產生氣泡現象，進而影響整體儲槽內部顆粒排放之穩定性。而儲槽排放過程之儲槽內部壓力變化亦為第一年度計畫之研究重點。第二年度計畫將針對粉顆粒於儲槽內排放過程之熱傳行為議題進行一系列的分析與研究。有鑒於儲槽式熱交換器之相關工業應用，本計畫也將探討逆流儲槽式熱交換器，其中逆流即意指顆粒排放流動方向與加熱氣體流動方向相反，也因如此顆粒於儲槽內之流動方式對於整體系統加熱效果也影響甚大，也是必須被重視的研究議題。第三年度計畫將針對儲槽內顆粒物料溼度與顆粒形狀對排放行為之影響進行探討。由於實際工業中相關儲倉應用，多少存在著物料中存在濕度(即微量液體之影響)或存在著不同的顆粒之形狀，而上述兩種因素對於整體儲倉排放的影響程度也都是不可被忽略，也是值得被探討的重要議題。本計畫將在學術上針對儲槽應用之物理意義做更深入的探討，目的在於將諸多相關儲槽顆粒流動現象做系統性的解釋，相信研究成果將為相關領域帶來有用的資訊，且對相關業界應用提供後續發展潛力與方向，並對產業發展將有極大的貢獻。 ;Many materials in nature exist in the form of particles, such as gravel, stones, grains, and so on. The granular raw materials also can be found in the food industry, chemical industry, and pharmaceutical industry. Therefore these industries usually need to use silos, tanks, or hoppers for the storage of particles. The silo are used for the management of storage powder or particulate materials, and could control the discharge flow rate of the particles. For the size of the silo, it could be as large as the storage bins for storing cereals, feed and cement, and could be as small as the hourglasses. For the usage of silo, it can be sorted by long-term storage, short-term storage, re-stored and discharged, or filled into containers of the silo. However, the technique thresholds of the control of the discharge becomes harder for larger-scaled silo.This three-year project will study the granular discharge and heat transfer behavior in the silo. The first year of the project will investigate the discharge behavior of fine particles in a storage silo. Due to the discharge process of the storage silo is a two-phase flow, the influence of the interstitial fluid is very important. The interstitial fluid may usually accumulate in the storage silo to generate the bubbles. The flow behavior of the bubbles in the storage silo may affect the stability of the discharge process. The pressure variations inside the silo during the discharge process will also be studied in the first-year project. The second year of the project will conduct a series of analyses and investigations on the issue of heat transfer behavior of particles during the discharge process. The storage-silo-style heat exchanger is often be used in industrial applications. The second-year project will discuss the counter-current-storage-silo style heat exchanger, in which counter-current means that the flow direction of the granular discharge is opposite to the direction of the heating gas flow. The granular flow conditions in the silo also has a crucial influence on the overall heating effect, and it is also an important research issue. The third year of the project will discuss the effects of liquid on the granular material and the shape of the particles on the discharge behavior in the silo. Due to the relevant storage silo applications in the industry, there exists humidity in the material or the different shape of particles in the silo. The influence of the two effects above on the overall discharge process could not be ignored, and is also an important issue, and worth to investigate. |
