本文選題：冷卻塔填料 + 數(shù)值模擬��； 參考：《山東大學》2017年碩士論文

【摘要】：在電廠中,冷卻塔的作用就是冷卻溫度較高的冷卻水,通過塔內(nèi)冷卻水與空氣的熱量交換將熱量擴散到空氣中。在冷卻塔內(nèi)部,其冷卻性能主要受填料的熱力性能、運行的外界溫度、給水量、外界風速、除水器等的影響。填料是冷卻塔內(nèi)非常重要的換熱元件,分析其內(nèi)部的氣液換熱性能對分析冷卻塔的性能有重要意義。液膜的流動形態(tài)受到很多因素的影響,包括液體性質、壁面材質、壁面結構、風速、水速等,而液膜的形態(tài)是影響換熱效果的重要因素,因此,本文從液膜形態(tài)的角度分析填料通道內(nèi)氣液兩相流的流動與換熱。本文首先通過壁面等效法建立了填料內(nèi)氣液兩相逆向流動換熱的數(shù)值計算模型,并通過對比與其他學者的計算結果驗證了模型的準確性。通過此模型計算了彎曲的填料通道內(nèi)的氣液兩相逆流換熱的情況,分析了液相的流動狀態(tài)隨時間的變化。給出了填料通道內(nèi)的溫度場、壓力場、液膜形態(tài)等參數(shù)隨風速、水速、通道傾斜角度變化的規(guī)律。通過對模擬計算結果分析可知,在電廠的工況范圍內(nèi)提高風速能夠有效的提高填料通道內(nèi)的持液量,冷卻效率,降低阻力系數(shù)。在電廠工況范圍內(nèi)提高進水速度使得填料通道內(nèi)的液膜流動狀態(tài)變差,冷卻效率下降且阻力系數(shù)增加。文中分析了兩種傾斜角的填料通道內(nèi)液膜流動形態(tài)的差異,熱力特性的差異,由結果表明,30°傾斜角的模型在冷卻效果方面比45°和60°傾斜角的模型差,但在阻力方面比45°與60°傾斜角模型好,因此填料的傾斜角度的設置與實際工程的需求是相關的。通過計算三維通道內(nèi)氣液兩相逆流過程的流動狀態(tài)與換熱,分析了三維通道內(nèi)氣液流動過程與氣水比的關系,給出了流態(tài)、冷卻效率、阻力系數(shù)隨氣水比變化的關系。通過分析計算結果可知,隨著氣水比的增加,填料通道內(nèi)的冷卻效率明顯提高,且阻力系數(shù)有小幅度的減小。本文對不同的填料結構進行研究,分析了填料通道結構與熱力特性的關系。給出了三種孔徑的填料模型在液膜流動狀態(tài),持液量,溫度場、冷卻效率,阻力系數(shù)等參數(shù)的不同,并對影響差異的因素進行深入分析。通過對比結果發(fā)現(xiàn),由于比表面積的差別,隨著填料孔徑的減小冷卻效率有明顯的提高�？s小后的阻力系數(shù)比改進前的結構有明顯的減小。給出了三種波形的填料模型在冷卻效率和阻力系數(shù),并對影響因素進行了分析。由于S波通道其結構最復雜、持液量最大、比表面積最大,所以冷卻效率最高,而斜波的比表面積最小其冷卻效率最低。斜折波由于其結構上的優(yōu)勢而阻力系數(shù)最小,S波由于其彎曲通道的復雜性,其阻力系數(shù)最大。
[Abstract]:In the power plant, the cooling tower is used to cool the cooling water with higher temperature, which diffuses the heat into the air through the heat exchange between the cooling water and the air in the tower. In the cooling tower, the cooling performance is mainly affected by the thermal performance of the filler, the external temperature of the operation, the water supply, the external wind speed, the water remover and so on. Packing is a very important heat transfer element in cooling tower. It is very important to analyze the gas-liquid heat transfer performance of cooling tower. The flow pattern of liquid film is affected by many factors, including liquid property, wall material, wall structure, wind speed, water velocity and so on. In this paper, the flow and heat transfer of gas-liquid two-phase flow in packing channel are analyzed from the point of view of liquid film morphology. In this paper, the numerical model of heat transfer of gas-liquid two-phase reverse flow in packing is established by wall equivalent method, and the accuracy of the model is verified by comparing the results with those of other scholars. Through this model, the heat transfer of gas-liquid two-phase countercurrent in the curved packing channel is calculated, and the change of liquid phase flow state with time is analyzed. The variation of temperature field, pressure field and liquid film shape with wind speed, water velocity and channel inclination angle are given. Through the analysis of the simulation results, it can be seen that increasing the wind speed in the power plant can effectively increase the liquid holdup, cooling efficiency, and reduce the resistance coefficient in the packing channel. Increasing the influent speed in the power plant makes the liquid film flow in the packing channel worse, the cooling efficiency decreases and the resistance coefficient increases. In this paper, the differences of liquid film flow patterns and thermodynamic characteristics in two kinds of tilted packing channels are analyzed. The results show that the model of 30 擄tilting angle is worse in cooling effect than that of 45 擄and 60 擄tilting angles. But the resistance is better than that of 45 擄and 60 擄angle model, so the setting of the tilting angle of packing is related to the requirement of practical engineering. By calculating the flow state and heat transfer of gas-liquid two-phase countercurrent in three-dimensional channel, the relationship between gas-liquid flow process and gas-water ratio in three-dimensional channel is analyzed, and the relationship among flow state, cooling efficiency and resistance coefficient with gas-water ratio is given. The results show that with the increase of air-water ratio, the cooling efficiency in the packing channel is obviously increased, and the resistance coefficient is reduced to a small extent. In this paper, different packing structures are studied, and the relationship between packing channel structure and thermal characteristics is analyzed. In this paper, three kinds of packing models with pore diameter are given, and the factors influencing the difference are analyzed, such as the flow state of liquid film, liquid holdup, temperature field, cooling efficiency, resistance coefficient and so on. The results show that the cooling efficiency increases with the decrease of packing aperture due to the difference of specific surface area. The reduced resistance coefficient is obviously smaller than that of the improved structure. The cooling efficiency and drag coefficient of the packing models with three waveforms are given, and the influencing factors are analyzed. Due to the most complex structure, the largest liquid holdup and the largest specific surface area of the S-wave channel, the cooling efficiency is the highest, while the minimum specific surface area of the oblique wave is the lowest. The resistance coefficient of oblique fold wave is the smallest because of its advantage in structure. Because of the complexity of the curved channel, the resistance coefficient is the largest.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM62

【相似文獻】

相關期刊論文 前7條

1 凈水;;新型折波填料在玻璃鋼冷卻塔中的應用[J];凈水技術;1984年04期

2 史佑吉;;冷卻塔塑料淋水填料的特性及應用[J];電力技術;1986年09期

3 胡三季;陳玉玲;;冷卻塔塑料淋水填料熱力及阻力性能分析[J];熱力發(fā)電;1992年04期

4 蔡錫龍;于秋江;;雙斜波淋水填料的設計與性能研究[J];凈水技術;1993年01期

5 徐平;;冷卻塔塑料淋水填料熱力及阻力特性的分析[J];電力建設;1993年12期

6 李德興;;論引進大化肥冷卻塔的現(xiàn)狀及其對策[J];凈水技術;1991年03期

7 華衛(wèi);於勝洪;董紅明;費曉秋;朱加征;;不同填料下UBAF深度處理印染廢水的對比研究[J];中國給水排水;2011年21期

相關碩士學位論文 前10條

1 王韜;新型大通量填料的流體力學和傳質性能研究及其CFD模擬[D];北京化工大學;2015年

2 王辰晨;泡沫碳化硅填料內(nèi)的流場模擬及結構優(yōu)化[D];天津大學;2014年

3 汪天尖;蒸發(fā)冷卻填料的除塵性能研究[D];廣州大學;2015年

4 劉珊;濕式冷卻塔填料通道幾何特性對于熱力性能的影響研究[D];山東大學;2017年

5 蔡笠;幾種填料在生物接觸氧化工藝中的應用特性及工藝改良研究[D];哈爾濱工業(yè)大學;2011年

6 黃凱;冷卻塔淋水填料特性及結構優(yōu)化實驗研究[D];東華大學;2014年

7 李萌;微電解填料的制備及其在有機廢水處理中的應用[D];吉林大學;2011年

8 侯雯;BAF后置富鐵填料強化除磷效果的研究[D];蘭州交通大學;2013年

9 焦緯洲;錯流旋轉床填料結構與特性研究[D];中北大學;2006年

10 崔敏華;ABR工藝改造工程的數(shù)值模擬及水力特性研究[D];哈爾濱工程大學;2013年

，

本文編號：1813406