本文選題：實驗室通風 + 數(shù)值模擬　； 參考：《廣州大學》2015年碩士論文

【摘要】：實驗室作為科研工作的重要場所,通常具有能耗大、實驗人員工作環(huán)境危險性大、空氣污染嚴重等問題。另外,實驗設備大量排風所帶來的高能耗與局部強排風之間矛盾一直是實驗室通風設計的焦點。如何有效地對實驗室進行通風換氣,保證局部排風設備對污染物的控制能力,達到既安全又節(jié)能的效果是實驗室通風設計的重大難題。本文從實驗室氣流組織形式出發(fā),利用FLUENT計算軟件建立了不同氣流組織形式下實驗室房間的數(shù)值分析模型,并用實驗數(shù)據(jù)對數(shù)值分析模型的可靠性進行了驗證。就排風柜的面風速、污染物類型等因素對實驗室及排風柜人體周圍的污染物濃度、室內(nèi)的速度、溫度的影響進行了數(shù)值模擬分析。研究結(jié)果表明:送風速度及送風口與排風柜罩面間的水平距離均會影響排風柜內(nèi)的氣流分布;通過對密度較大污染物sf6(為空氣密度5倍左右)和對密度較小的污染物NO2、NH3(分別為空氣密度的1.6倍、0.5倍左右)的分析,不同氣流組織形式中對實驗污染物排除效果較好的是下送上回的置換通風氣流組織和上送下回的混合通風氣流組織形式。針對目前實驗室工作人員認為排風柜面風速越大,污染物逸出的可能性越小的觀念,對排風柜采用不同面風速的情況進行了數(shù)值模擬分析。研究結(jié)果表明:當排風柜面風速大于0.3m/s時,排風柜操作口的平均污染物濃度明顯降低,而面風速從0.5m/s增至0.7m/s時,污染物濃度值雖有微小的降低,但排風柜性能沒有明顯的改善,考慮到較高的面風速大大增加了風機的能耗,不利于節(jié)能。0.5m/s的排風柜面風速已滿足將污染物濃度控制在安全限值以下,完全可以保護實驗人員的安全,沒有必要采用很大的排風柜面風速,造成不必要的能源浪費。文中分析了不同氣流組織形式下的實驗室能耗。研究結(jié)果表明:在相同的實驗室送風量條件下,置換通風的氣流組織形式由于送風溫度高,所需的制冷量低于混合通風,但是其再熱能耗高于混合通風,如果在實驗室應用熱管等熱回收裝置,可以節(jié)省再熱能耗。注意到置換通風的通風效率高于混合通風,且在過渡季節(jié)可延長利用室外新風免費供冷的時間,降低機械制冷的能耗。在過渡季節(jié)較長且較干燥的地區(qū),實驗室應用置換通風比混合通風具有更大的節(jié)能潛力。
[Abstract]:As an important place for scientific research, the laboratory usually has many problems, such as high energy consumption, dangerous working environment, serious air pollution and so on.In addition, the contradiction between high energy consumption and local strong ventilation caused by a large amount of exhaust air from experimental equipment has always been the focus of laboratory ventilation design.How to effectively ventilate the laboratory to ensure the ability of local ventilation equipment to control pollutants and to achieve the effect of safety and energy saving is a major problem in the design of laboratory ventilation.In this paper, the numerical analysis model of the laboratory room under different airflow organization forms is established by using the FLUENT calculation software, and the reliability of the numerical analysis model is verified by the experimental data.In this paper, the effects of surface wind speed and pollutant type on the concentration, velocity and temperature of pollutants around the body in laboratory and exhaust cabinet are analyzed numerically.The results show that both the velocity of air supply and the horizontal distance between the air outlet and the cover surface of the exhaust cabinet will affect the distribution of air flow in the exhaust tank.Through the analysis of the higher density pollutant sf6 (about 5 times the air density) and the less dense pollutant no _ 2 (NH _ 3) (about 1.6 times the air density about 0.5 times of the air density),Among the different air distribution forms, the better removal effect of experimental pollutants is the downward return displacement ventilation airflow organization and the upward and lower return mixed ventilation airflow organization form.Aiming at the idea that the larger the wind speed of the exhaust cabinet is, the less likely the pollutants will escape, the paper makes a numerical simulation analysis on the situation that the exhaust cabinet adopts different surface wind speed.The results show that when the wind speed of exhaust cabinet is greater than 0.3m/s, the average pollutant concentration of outlet is obviously decreased, while the concentration of pollutants decreases slightly when the surface wind speed increases from 0.5m/s to 0.7m/s, but the performance of exhaust tank does not improve obviously.Considering that the high surface wind speed greatly increases the energy consumption of the fan, and is not conducive to saving energy. 0.5 m / s of exhaust air speed has been satisfied with the concentration of pollutants below the safety limit, which can completely protect the safety of the experimenter.There is no need to use a large exhaust cabinet wind speed, resulting in unnecessary energy waste.In this paper, the energy consumption of the laboratory under different airflow organization forms is analyzed.The results show that under the same air supply rate in laboratory, the cooling capacity of displacement ventilation is lower than that of mixed ventilation because of its high air temperature, but its reheat energy consumption is higher than that of mixed ventilation.If the heat recovery device such as heat pipe is applied in the laboratory, the reheat energy consumption can be saved.It is noted that the ventilation efficiency of displacement ventilation is higher than that of mixed ventilation and the free cooling time of outdoor fresh air can be prolonged during the transition season and the energy consumption of mechanical refrigeration can be reduced.In the longer transitional season and drier areas, the laboratory application of displacement ventilation has greater energy saving potential than mixed ventilation.
【學位授予單位】：廣州大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X51;TU834

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本文編號：1759928