本文關鍵詞： 蓄冷 冰漿 乳液 納米粒子　出處：《蘇州科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：隨著我國社會和經濟的發(fā)展,電力需求也日益增長,高能耗、能源分布不均和電網峰谷差等問題逐漸突顯出來。蓄冷空調是一種可以充分利用低谷電的節(jié)能技術,是電力“移峰填谷”和解決尖峰電力不足的有效方法。目前水和冰是應用最廣泛的蓄冷介質,其中水蓄冷是利用顯熱蓄冷,蓄冷密度低,但具有較好的流動性;冰蓄冷利用潛熱蓄冷,蓄冷密度大但無法直接輸送冷量。冰漿是冰晶粒子均勻分布的固液兩相流體,同時兼顧了水蓄冷的流動性和冰蓄冷蓄冷密度大的優(yōu)點。冰漿以其良好的熱物理性質,在作為一種新型無污染的蓄冷及載冷介質等方面具有重大的研究價值和廣闊的應用前景。在冰漿制取、運輸和儲存過程中,克服冰堵和提高流動性是其推廣應用的關鍵,也是當前冰蓄冷技術的研究熱點。本文在油-水中添加少量添加劑(硅烷偶聯(lián)劑、表面活性劑+乙醇)配制了兩組實驗體系,通過攪拌降溫制備了乳液冰漿,得到乳液的冰點和過冷度,觀察了冰晶粘附壁面情況、冰粒大小和冰漿流動性。采用混合量熱法研究表面活性劑和乙醇對冰漿含冰率的影響,通過旋轉粘度計、顯微鏡分別測定表觀粘度和冰粒粒徑,表征乳液冰漿的蓄冷性能和流動性能。實驗結果表明表面活性劑Span80、T80和油酸阻礙了冰晶的團聚,提高了冰晶的分散均勻性,但不影響冰漿含冰率。乙醇的添加,降低了冰漿的冰點和含冰率,增大了過冷度,但抑制了壁面冰層的出現(xiàn)。冰漿表觀粘度和冰粒粒徑都隨著含冰率的增加而增加。當恒溫空氣浴為-8.5℃,結晶時間為90min時,添加劑成分為E2.6(1.0wt%Span80+3.0wt%ET)、E2.17(2.0wt%T80+4.0wt%ET)、E2.23(0.5wt%油酸+3.0wt%ET)冰漿的冰點分別為-1.8℃、-2.3℃和-1.8℃,過冷度分別為4.1℃、4.5℃和4.2℃,含冰率分別為31.6%、32.2%、32.2%,表觀粘度分別為47.0 mPa·s、32.0 mPa·s、25.5mPa·s,粒徑分別為1.34mm、1.60mm、2.00mm,形成的冰漿含冰率高,流動阻力小,冰晶不粘附壁面,是代替硅烷偶聯(lián)劑作為冰漿添加劑的配比方案。為了減小冰漿的過冷度,本文采用超聲震蕩方法將納米CuO粒子分散到乳液冰漿中,通過重力沉降和分光度來表征納米流體的分散穩(wěn)定性,篩選出分散效果好的實驗體系。采用混合量熱法測試了含有納米CuO乳液冰漿的含冰率,并獲得了冰漿形成的相變溫度、過冷度,采用T-history方法計算出其比熱容和導熱系數(shù),研究了納米CuO粒子質量分數(shù)對比熱容、導熱系數(shù)、相變溫度、過冷度和含冰率的影響。實驗結果表明納米CuO的加入,對冰漿相變溫度的影響不大,降低了冰漿的比熱容和過冷度,提高了冰漿的導熱系數(shù)和含冰率,有效地克服了乙醇的不利影響,起到了促晶成核、增強傳熱的作用,提高了冰漿的蓄冷性能。
[Abstract]:With the development of our country's society and economy, the demand for electric power is increasing day by day. The problems of high energy consumption, uneven distribution of energy and difference between peak and valley of power grid are becoming more and more obvious. Storage air conditioning is a kind of energy saving technology which can make full use of low power. At present, water and ice are the most widely used cold storage medium, in which water storage is the use of sensible heat storage, the cold storage density is low, but it has good fluidity. Ice storage is a solid-liquid two-phase fluid with uniform distribution of ice crystal particles. At the same time, the fluidity of water storage and the advantages of high density of ice storage are taken into account. It has great research value and broad application prospect as a new kind of non-pollution cold storage and carrier cold medium. In the process of ice slurry manufacture, transportation and storage, overcoming ice blocking and improving fluidity are the key to its popularization and application. In this paper, a small amount of additives (silane coupling agent, surfactant ethanol) were added to the oil and water to prepare two groups of experimental systems, and the emulsion ice slurry was prepared by stirring and cooling down. The freezing point and undercooling degree of the emulsion were obtained. The ice crystal adhesion to the wall, the ice particle size and the ice slurry fluidity were observed. The effects of surfactant and ethanol on the ice content of ice slurry were studied by mixing calorimetry. The apparent viscosity and ice particle size were measured by microscope to characterize the cold storage property and fluidity of ice slurry. The experimental results showed that the surface active agent Span80 T80 and oleic acid hindered the aggregation of ice crystals and improved the dispersion uniformity of ice crystals. But it has no effect on the ice content of the ice slurry. The addition of ethanol reduces the freezing point and ice content of the ice slurry and increases the degree of undercooling. But the appearance of wall ice layer was inhibited. The apparent viscosity and particle size of ice slurry increased with the increase of ice content. When the temperature of air bath was -8.5 鈩，

本文編號：1547289