本文選題：光熱轉(zhuǎn)換　切入點：納米流體　出處：《青島科技大學》2017年碩士論文

【摘要】：化石能源危機與環(huán)境污染是目前最嚴重的世界性難題,尋找可替代化石能源的清潔能源是當務(wù)之急。其中太陽能獲取容易、總量大、清潔安全、對環(huán)境友好,從而成為研究的重點。納米流體在太陽能光熱利用方面有非常好的前景,光熱轉(zhuǎn)換納米流體的制備與性能研究對太陽能光熱利用具有重要意義。本文通過分散法制備了ZrC/水納米流體,借助XRD和TEM對Zr C納米顆粒的組成、形貌進行了表征,通過沉降法研究了ZrC/水納米流體的穩(wěn)定性,搭建了光熱轉(zhuǎn)換性能測試裝置,改進了光熱轉(zhuǎn)換效率的計算方法,研究了其光吸收、光熱轉(zhuǎn)換性能。結(jié)果表明:納米流體經(jīng)超聲30分鐘,PVP分散劑加入量為碳化鋯質(zhì)量的8-10%時穩(wěn)定性最好;納米流體的透過率隨固含量增加而降低;當光程為1cm、固含量為0.02 wt%時太陽光幾乎全吸收,太陽加權(quán)吸收系數(shù)Am達到0.99;太陽光模擬條件下,0.02 wt%ZrC納米流體的最大溫升為38.2℃,光熱轉(zhuǎn)換效率為92%。這種效率計算方法考慮了熱量的散失,因而能更合理的評價納米流體光熱轉(zhuǎn)換性能。通過研磨法制備了WC/水納米流體,研究了分散劑種類、加入量對納米流體穩(wěn)定性的影響,研究了納米流體的光吸收、光熱轉(zhuǎn)換性能。結(jié)果表明:選擇2 wt%的PVA作為分散劑可以得到穩(wěn)定的納米流體;WC納米流體的光吸收隨固含量增加而增強,當光程為1 cm時,0.3 wt%WC納米流體的Am為0.99;太陽光模擬條件下,固含量為0.3 wt%的WC納米流體最大溫升為39.5℃,光熱轉(zhuǎn)換效率為97%,是理想的太陽能吸收體。以WC納米流體為光熱轉(zhuǎn)換介質(zhì)搭建了太陽能水蒸發(fā)試驗裝置,利用納米流體局部加熱水蒸發(fā)提高太陽能利用率,通過增加納米流體濃度來提高蒸發(fā)效率。和純水整體蒸發(fā)相比,蒸發(fā)量、蒸發(fā)速率顯著增大,使用0.3 wt%的WC納米流體蒸發(fā)速率為1.53 kg·m-2·h-1;與純水空白對照組相比,使用0.3 wt%的WC納米流體蒸發(fā)效率增加23%,這為納米流體在太陽能水蒸發(fā)及海水淡化領(lǐng)域提供新的思路。碳化鋯和碳化鎢納米流體均表現(xiàn)出寬波段吸收特性,可以顯著增強對太陽輻射的吸收,這些工作對光熱轉(zhuǎn)換納米流體在太陽能利用領(lǐng)域的應(yīng)用具有重要意義。
[Abstract]:The crisis of fossil energy and environmental pollution are the most serious problems in the world at present. It is urgent to find clean energy that can replace fossil energy. Among them, solar energy is easy to obtain, large amount of energy, clean and safe, and friendly to the environment. This has become the focus of research. Nanofluids have a very good prospect in solar photothermal utilization. The preparation and properties of photothermal conversion nanofluids are of great significance to the photothermal utilization of solar energy. In this paper, ZrC/ water nanofluids were prepared by dispersion method. The composition and morphology of ZrC nanoparticles were characterized by XRD and TEM. The stability of ZrC/ water nanofluids was studied by sedimentation method, the photothermal conversion performance test device was built, the calculation method of photothermal conversion efficiency was improved, and its optical absorption was studied. The results showed that the stability of nano-fluid was the best when the amount of PVP dispersant was 8-10% of the mass of zirconium carbide, and the transmittance of nano-fluid decreased with the increase of solid content. When the light path is 1 cm and the solid content is 0.02 wt%, the solar light absorption coefficient am is 0.99.The maximum temperature rise of 0.02 wt%ZrC nanoscale fluid is 38.2 鈩，

本文編號：1698734