本文選題：熱工學　切入點：蒸發(fā)式冷凝器　出處：《天津商業(yè)大學》2014年碩士論文　論文類型：學位論文

【摘要】：隨著冷凍冷藏業(yè)的快速發(fā)展，勢必增加能源的消耗，能源日漸短缺已經(jīng)成為不爭的事實，近年霧霾頻現(xiàn)也使人們面對著巨大的挑戰(zhàn)，因此節(jié)能環(huán)保型設備的開發(fā)和應用具有重要的意義。 蒸發(fā)式冷凝器是一種高效的換熱設備，因其具有節(jié)能、節(jié)水、占地少等優(yōu)點，，被廣泛應用于制冷行業(yè)。蒸發(fā)式冷凝器傳熱性能的研究對提高蒸發(fā)式冷凝制冷系統(tǒng)具有重要的意義。蒸發(fā)式冷凝器傳熱過程十分復雜，需進行詳細的研究。 為研究蒸發(fā)式冷凝器性能，搭建蒸發(fā)式冷凝器制冷實驗臺。通過理論分析和實驗研究相結(jié)合的方法，研究逆流式蒸發(fā)式冷凝器的傳熱傳質(zhì)性能，主要研究迎面風速和噴淋密度對傳熱傳質(zhì)的影響，并在同一實驗條件下對比了順流和逆流兩種形式的蒸發(fā)式冷凝器的傳熱傳質(zhì)性能，得到如下結(jié)論： 1）風速和噴淋密度是影響蒸發(fā)式冷凝器的兩大關鍵因素�？倐鳠嵯禂�(shù)隨著風速的增大而增大然后趨于平緩，隨著噴淋密度的增大而增大。風速主要影響空氣對流傳熱系數(shù)，噴淋密度影響水膜傳熱系數(shù)。 2）對于結(jié)構(gòu)給定的蒸發(fā)式冷凝器單位傳熱面積存在最佳風量和水量。本實驗臺所在測試條件下，逆流式蒸發(fā)式冷凝器最佳單位傳熱面積風量和水量為277.4m3/(h·m2)和0.63kg/(h·m2)，對應的迎面風速和最佳噴淋密度分別為2.96m/s和0.057kg/（m·s）；順流式蒸發(fā)式冷凝器最佳單位傳熱面積風量和水量為307.4m3/(h·m2)和0.75kg/(h·m2)，對應的迎面風速和最佳噴淋密度分別為3.28m/s和0.068kg/（m·s），對蒸發(fā)式冷凝器的開發(fā)和設計有一定的指導意義。 3）逆流式蒸發(fā)式冷凝器比順流式蒸發(fā)式冷凝器具有優(yōu)越的傳熱性能，在實驗條件下，傳熱系數(shù)前者比后者高17.2%。逆流式蒸發(fā)式冷凝器風速不宜過高，易產(chǎn)生液泛現(xiàn)象，影響傳熱性能。 4）設計過程中不僅考慮蒸發(fā)式冷凝器的傳熱性能，而且要考慮整個系統(tǒng)的性能，使EER達到最佳值。逆流式蒸發(fā)式冷凝器比順流式蒸發(fā)式冷凝器高近8.2%。 5）蒸發(fā)式冷凝器主要利用蒸發(fā)潛熱吸收熱量，具有很高的傳熱系數(shù)。對比干工況和正常工況，前者的總傳熱系數(shù)約為后者的1/10左右。 研究結(jié)果對蒸發(fā)式冷凝器的研究和開發(fā)具有一定的指導意義，且對逆流式蒸發(fā)式冷凝器的實驗研究，對以后研究蒸發(fā)式冷凝器傳熱傳質(zhì)性能，提供了可靠的參考數(shù)據(jù)。
[Abstract]:With the rapid development of frozen cold storage industry, it is bound to increase energy consumption, energy shortage has become an indisputable fact, in recent years, haze frequency also makes people face a huge challenge. Therefore, the development and application of energy-saving and environmental-friendly equipment is of great significance. Evaporative condenser is an efficient heat exchanger, which has the advantages of saving energy, saving water and occupying less land. It is widely used in refrigeration industry. The study of heat transfer performance of evaporative condenser is of great significance to improve the evaporative condenser refrigeration system. The heat transfer process of evaporative condenser is very complex and needs to be studied in detail. In order to study the performance of evaporative condenser, an experimental bench of evaporative condenser was built. The heat and mass transfer performance of countercurrent evaporative condenser was studied by combining theoretical analysis with experimental research. The effects of wind speed and spray density on heat and mass transfer are studied. The heat and mass transfer performance of the evaporative condenser is compared under the same experimental conditions, and the conclusions are as follows:. 1) Wind speed and spray density are the two key factors affecting evaporative condenser. The total heat transfer coefficient increases with the increase of wind speed and then tends to be gentle, and increases with the increase of spray density. The wind speed mainly affects the convection heat transfer coefficient of air. Spray density affects the heat transfer coefficient of water film. 2) for the unit heat transfer area of the evaporative condenser with a given structure, there exists the optimum air volume and water quantity. The best unit heat transfer area air volume and water volume of countercurrent evaporative condenser are 277.4 m3 / h 路m2) and 0.63 kg / m ~ (-1) h 路m ~ 2 路m ~ (2), corresponding to the forward wind speed and optimum spray density are 2.96 m / s and 0.057 kg / m 路s ~ (-1), respectively, and the optimum air volume and water volume per unit heat transfer area of the downstream evaporative condenser are 307.4 m ~ 3 / h 路m ~ 2 路m ~ (2). The corresponding wind speed and optimum spray density are 3.28 m / s and 0.068 kg / m 路s-1 respectively, which are of certain guiding significance to the development and design of evaporative condenser. 3) the countercurrent evaporative condenser has better heat transfer performance than the downstream evaporative condenser. Under the experimental conditions, the heat transfer coefficient of the former is 17.2% higher than that of the latter. Affect heat transfer performance. 4) not only the heat transfer performance of evaporative condenser is considered in the design process, but also the performance of the whole system should be considered to make the EER reach the optimum value. The countercurrent evaporative condenser is nearly 8.2 higher than the downstream evaporative condenser. 5) the evaporative condenser mainly absorbs heat by evaporative latent heat and has a high heat transfer coefficient, and the total heat transfer coefficient of the former is about 1/10 of that of the latter. The results are of certain significance for the research and development of evaporative condenser and provide reliable reference data for the experimental study of countercurrent evaporative condenser and for the later study of heat and mass transfer performance of evaporative condenser.
【學位授予單位】：天津商業(yè)大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TB657;TK124

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