本文選題：泡沫瀝青　切入點：發(fā)泡過程　出處：《長安大學(xué)》2014年碩士論文

【摘要】：我國是公路里程的大國，每年產(chǎn)生的瀝青路面廢舊材料就高達(dá)上億噸，而對廢舊材料的利用率卻非常低。近幾年來，國內(nèi)開始引進(jìn)泡沫瀝青冷再生設(shè)備來改善這種情況。泡沫瀝青技術(shù)中發(fā)泡裝置是至關(guān)重要的部分，揭示瀝青發(fā)泡過程，確定發(fā)泡裝置的結(jié)構(gòu)及工藝參數(shù)，設(shè)計有效、合理的發(fā)泡裝置對泡沫瀝青技術(shù)的研究具有重要的意義。瀝青發(fā)泡過程的研究，對改善發(fā)泡效果和泡沫瀝青的實際應(yīng)用具有重要的理論和工程意義。 根據(jù)瀝青的實際發(fā)泡過程，建立了瀝青發(fā)泡膨脹過程仿真模型，利用先進(jìn)計算流體力學(xué)軟件Fluent,首次對瀝青噴出發(fā)泡腔外的實際發(fā)泡膨脹過程進(jìn)行模擬研究，建立了模擬結(jié)果與實驗數(shù)據(jù)之間的直接關(guān)聯(lián)關(guān)系。通過仿真數(shù)據(jù)與實驗數(shù)據(jù)的對比分析，驗證了建立的瀝青發(fā)泡過程的仿真模型基本符合實際瀝青發(fā)泡過程。 利用建立的仿真模型，研究了發(fā)泡條件參數(shù)對發(fā)泡膨脹率的影響，分析得出發(fā)泡用水量和發(fā)泡過程中的空氣壓力對發(fā)泡膨脹率的影響并不顯著，而發(fā)泡用瀝青的溫度和瀝青的流量對發(fā)泡膨脹率的影響比較顯著。發(fā)泡用水量在1.5%到2.5%范圍變化和發(fā)泡過程中的空氣壓力在0.3MPa到0.6MPa范圍變化時對發(fā)泡膨脹率的影響不明顯，當(dāng)瀝青入口流量從100g/s到180g/s變化時和瀝青溫度從150℃到170℃變化時，，膨脹率是一個穩(wěn)定增長的過程。 建立了發(fā)泡腔內(nèi)仿真模型，利用Fluent軟件對發(fā)泡腔內(nèi)部的多相耦合場進(jìn)行了分析。在發(fā)泡過程中，空氣的吹入可以促進(jìn)水汽與瀝青的碰撞、附著，增加水汽被瀝青包裹的機(jī)會�？諝獠粎⑴c相變和瀝青的發(fā)泡過程，但可以改善發(fā)泡效果，同時，減少了瀝青與發(fā)泡腔的粘附，并起到清潔發(fā)泡腔的作用。瀝青和水的入口角度、速度直接影響瀝青和水汽的混合效果，導(dǎo)致瀝青的發(fā)泡效果不同。發(fā)泡過程的水用于產(chǎn)生水蒸氣，并為瀝青泡沫膨脹提供動力。發(fā)泡中的高溫瀝青一方面為水的蒸發(fā)提供熱量；另一方面，包裹水汽泡，形成瀝青泡沫。 利用有限元數(shù)值模擬方法，通過對發(fā)泡腔內(nèi)、外瀝青發(fā)泡過程的數(shù)值模擬，可以有效地對所設(shè)計的發(fā)泡腔結(jié)構(gòu)、發(fā)泡效果及其影響因素進(jìn)行一定的預(yù)先評價，對實際發(fā)泡設(shè)備的生產(chǎn)及應(yīng)用具有一定的指導(dǎo)意義。
[Abstract]:China is a large country of highway mileage, producing hundreds of millions of tons of used asphalt pavement materials every year, but the utilization ratio of waste materials is very low. In recent years, In order to improve the situation, the foaming device is the most important part in the foamed asphalt technology, which reveals the foaming process of asphalt, determines the structure and technological parameters of the foaming device, and is effective in design. The reasonable foaming device is of great significance to the study of foamed asphalt technology, and the study of the foaming process of asphalt has important theoretical and engineering significance for improving the foaming effect and the practical application of foamed asphalt. According to the actual foaming process of asphalt, the simulation model of asphalt foaming and expanding process is established. The actual foaming and expanding process of asphalt ejecting foaming cavity is studied for the first time by using advanced computational fluid dynamics software Fluent. The direct correlation between the simulation results and the experimental data is established, and the simulation model of the asphalt foaming process is verified by comparing the simulation data with the experimental data, which basically accords with the actual asphalt foaming process. By using the simulation model, the influence of the foaming condition parameters on the foaming expansion rate is studied. The results show that the influence of water consumption and air pressure during foaming process on the foaming expansion rate is not significant. However, the influence of temperature and flow rate of foamed asphalt on the foaming expansion ratio is obvious. The influence of air pressure in the process of foaming is not obvious when the range of water consumption is 1.5% to 2.5% and the air pressure in the process of foaming varies from 0.3MPa to 0.6MPa. When the inlet flow rate of asphalt varies from 100g/s to 180g/s and the temperature of asphalt varies from 150 鈩

本文編號：1675718