本文關鍵詞：日光溫室不同厚度土墻蓄放熱特性研究　出處：《山東農業(yè)大學》2017年博士論文　論文類型：學位論文

  更多相關文章： 日光溫室 土質墻體厚度 蓄放熱特性 溫度場模擬

【摘要】：土質墻體的日光溫室因具有蓄放熱性能好、取材方便、成本低等優(yōu)點,深受廣大農民的青睞。目前,我國日光溫室土墻的厚薄差異較大,甚至有很大一部分為超厚土墻,墻體占地面積加大,造成土地資源浪費。日光溫室是我國獨有的溫室類型,其夜間維持作物生長的熱量主要來源于日間溫室墻體及地面吸收的太陽輻射熱量,研究日光溫室不同厚度土質墻體蓄放熱、接受太陽輻射得熱量及土墻體傳熱特性,對日光溫室土墻體建造的輕便化設計和提高土地利用率都具有十分重要的理論及實踐意義。本研究選取泰安市山東農業(yè)大學南校區(qū)建造的2棟土墻厚度不同的下挖式日光溫室為研究對象,在溫室北墻中間部位按不同高度設置5個測試層,每層水平布設溫度傳感器,室內墻體表面布設熱流傳感器及輻射計�；诟鳒y試層監(jiān)測的溫度、太陽輻射照度和熱流密度等數(shù)據,研究了不同天氣情況下土墻內溫度變化規(guī)律、各測試層太陽輻射量分布特性及土墻傳熱特性。主要結果如下:1.日光溫室土墻體內溫度變化分析及墻體放熱效率評價以泰安市3.0 m厚土墻下挖式日光溫室為研究對象,基于溫室北墻5個測試層最冷季節(jié)(30 d)溫室內氣溫、墻體溫度、室外氣溫及室外太陽輻照度測試數(shù)據,分析了土墻日光溫室內部空氣溫度及墻體內溫度的分布規(guī)律。結果表明:各測試層墻體表面及由表面至墻內0.1~0.6 m處測點的溫度均呈現(xiàn)出隨溫室內氣溫周期性變化而變化的規(guī)律,且隨著墻體厚度的增加溫度的波動幅值逐漸減小,時間相位明顯后移;0.7 m以后各測點的溫度波動幅值變化很小且趨于穩(wěn)定,處于穩(wěn)態(tài)向室外的導熱過程;由此可以推定:日光溫室后墻體內側約0.7 m的厚度為晝夜間蓄放熱的關鍵厚度�；趬w溫度分布、墻體白天蓄熱量、夜間的放熱量分析,計算得出墻體夜間放熱效率約為43%,表明土墻白天蓄積熱量的43%用于改善夜間溫室內熱環(huán)境。2.陰晴天情況下,日光溫室不同厚度土墻墻體蓄放熱特性基于晴好天氣(2015年12月30日—2016年1月2日)及連陰天氣(2016年1月4—6日)數(shù)據分析可知:連續(xù)晴好天氣及連陰天時,1#溫室厚墻體(頂寬2.0m,底寬6.0 m)和2#溫室薄墻體(頂寬1.0m,底寬3.0 m)的5個測試層的放熱量均為從第1層至第5層逐漸增加,兩溫室土墻體各層次的溫度變化趨勢相同;連續(xù)晴好天氣(2015年12月30日—2016年1月2日)時,1#厚墻體溫室和2#薄墻體溫室的5個測試層的每天平均蓄熱量分別為1971.2 k J和1888.9 k J,平均放熱量分別為808.1 kJ和763.1 kJ,1#和2#溫室的蓄熱量和放熱量的差值分別為82.3 k J和45.0 k J,數(shù)值差異很小。連陰天氣(2016年1月4—6日)的前兩天云層較薄有些散射光時,1#和2#溫室的蓄熱量都很小,第三天云層較厚,散射光也很弱,蓄熱量甚至為零,基本為全天放熱,平均放熱量分別為1551.4 k J和935.5 k J,兩溫室差值為615.9 k J,數(shù)值差異較大;雖然溫室厚墻體放熱量明顯高于薄墻體放熱量,但距離墻體內表面0.1 m處的平均氣溫也只差0.6℃,溫室內較前部的氣溫差異更小。從維持整個溫室內最低氣溫的效果來看其作用也是甚微。3.不同天氣狀況下日光溫室墻體5個測試層輻射得熱量分布及墻體傳熱量分布特性基于多云、多云轉陰、霧霾及晴好天氣2#溫室5個測試層采集數(shù)據,分析了各測試層接受太陽輻射量分布。結果表明:室外氣象條件對溫室接受太陽輻射強度的影響較大。晴好天氣時墻體各測試層接受的太陽輻射量明顯高于多云和輕度霧霾天氣,重度霧霾(測試天PM2.5指數(shù)253)和陰天接受輻射量非常小。墻體表面不同高度接受的太陽輻射量從上至下為第2測試層最大,其次是第3測試層,2和3測試層輻射總量值比較接近;再次為第4、第1和第5測試層。同時,基于上述不同天氣的墻體5測試層采集數(shù)據,分析了墻體5個測試層及后屋面向室外傳熱量分布特性。結果表明:北墻1~5個測試層的傳熱量占總傳熱量的比例依次為:第1測試層(墻體厚度為147 cm)約為21%,第2測試層(墻體厚度為186 cm)約為19%,第3測試層(墻體厚度為224 cm)約為17%,第4測試層(墻體厚度為263 cm)約為14%,第5測試層(墻體厚度為300 cm)約為12%,后屋面約為17%;溫室內熱量向室外的傳遞從低處至高處依次增強,因此,保溫隔熱措施應該是順勢加強。4.構建了日光溫室墻體溫度場模型基于ANSYS有限元分析軟件構建了求解日光溫室墻體溫度場的計算模型,以墻面實測溫度為自由度約束施加于模型邊界上,采用穩(wěn)態(tài)傳熱方法,模擬了陰晴天條件下不同時刻墻體內溫度場變化,并對模擬數(shù)據與實測數(shù)據進行比較分析,結果發(fā)現(xiàn)模擬曲線擬合較好,其模擬值與實測值的平均誤差為±1.0℃之內。利用ANSYS熱分析方法構建的墻體溫度場計算模型可以有效地預測溫室墻體內部溫度場的變化,能為泰安地區(qū)墻體設計及傳熱特性分析提供理論參考。
[Abstract]:The solar greenhouse in the soil wall has the advantages of good heat storage and heat storage, convenient material extraction and low cost, which are favored by the vast majority of farmers. At present, there is a large difference in the thickness of the earth wall in China's solar greenhouse, and even a large part of the earth wall is super thick, and the area of the wall is increased, which causes the waste of land resources. Solar greenhouse is our unique greenhouse type, the night to maintain calorie crop growth mainly from solar radiation heat wall and ground absorb daytime greenhouse, greenhouse of different thickness of soil wall heat storage, solar heat and heat transfer characteristics of the wall body, on greenhouse soil wall design and construction of light improvement has great theoretical and practical significance of land utilization. This study selected 2 wall thickness to build Tai'an city Shandong Agricultural University South Campus under different dig in greenhouse as the research object, in the middle part of the north wall of the greenhouse with different height to set up 5 test layers, each layer level distributed temperature sensor, indoor wall surface heat flux sensor and radiometer layout. Based on the data of monitoring temperature, solar irradiance and heat flux, the temperature variation rule of the earth wall, the distribution characteristics of the solar radiation and the heat transfer characteristics of the earth wall under different weather conditions are studied. The main results are as follows: analysis and evaluation of 1. greenhouse wall heat release rate in wall temperature changes in Tai'an city 3 m thick wall dug under the sunlight greenhouse as the research object, based on the north wall of the 5 layer of greenhouse test the coldest season (30 d) in the greenhouse temperature, wall temperature, outdoor air temperature and solar irradiance data. Analysis of temperature distribution of the internal wall of greenhouse air temperature and wall. The results showed that the test layer of wall surface and wall surface by 0.1~0.6 to m temperature measuring points were shown with the temperature indoor temperature cycle which changes with the increase of the thickness of wall temperature fluctuation amplitude decreases obviously after temporal phase shift; 0.7 m after each measuring point amplitude the temperature fluctuation is small and stable, steady heat conduction process to the outside; it can be presumed: greenhouse walls inside about 0.7 m thickness of the thickness of the heat storage key day and night. Based on wall temperature distribution, wall heat storage during the day and heat release at night, it is calculated that the night heat release efficiency of the wall is about 43%, indicating that 43% of the daily thermal storage capacity of the earth wall is used to improve the thermal environment in the greenhouse at night. 2. sunny days under greenhouse of different thickness of wall wall heat storage based on the characteristics of fine weather (December 30, 2015 - January 2, 2016) and overcast weather (January 2016 4 - 6 days) data analysis shows that: continuous fine weather and cloudy, greenhouse 1# thick wall (top width 2.0m, bottom width 6 m) and 2# thin greenhouse the wall (top width 1.0m, bottom width 3 m) 5 test layer heat is gradually increased from first to fifth, the two levels of greenhouse temperature change trend in the same soil wall; continuous fine weather (December 30, 2015 - January 2, 2016), the 5 layer of 1# thick wall temperature test chamber and 2# thin the average daily room wall temperature heat storage were 1971.2 K J and 1888.9 K J, the average heat release were 808.1 kJ and 763.1 kJ, the difference between 1# and 2# in greenhouse heat storage and heat release were 82.3 K J and 45 K J, the numerical difference is very small. Overcast weather (January 2016 4 - 6 days) two days before the thin cloud layer and some scattered light, the heat storage capacity of 1# and 2# in greenhouse is very small, the third day of thick clouds, scattered light is very weak, the heat storage capacity or even zero, is exothermic heat all day long, the average was 1551.4 K J and 935.5 K J, two of the greenhouse difference was 615.9 K J, numerical differences; although the greenhouse heat release was significantly higher than that of thick wall thin wall heat, but the average distance between the wall surface temperature at 0.1 M is only 0.6 degrees Celsius, the temperature in the greenhouse in front of the difference is smaller. The effect of maintaining the minimum temperature in the whole greenhouse is very small. 3. different weather conditions in the solar greenhouse wall 5 test layer of radiation heat distribution and wall heat transfer based on distribution characteristics of cloudy, cloudy, sunny weather haze and greenhouse 2# 5 layer test data collection, analysis of the test layer to receive solar radiation distribution. The results show that outdoor weather conditions have great influence on solar radiation intensity in greenhouse. The amount of solar radiation in sunny weather when the wall test layers accept was significantly higher than that in cloudy and mild haze, heavy haze (test day PM2.5 index 253) and cloudy accept the amount of radiation is very small. The solar radiation from different heights of the wall surface is second from the top to the bottom, the test layer is the largest, followed by the third test layer, 2 and 3, the radiation level of the test layer is relatively close, and the second is fourth, first and fifth test layer. At the same time, based on the different weather wall 5 test data acquisition layer, analyzed the 5 test layer and the back wall outside the room for heat distribution characteristics. The results show that the heat transfer from the north wall 1~5 test layer of total heat transfer ratio is as follows: first the test layer (wall thickness of 147 cm) is about 21%, second test layer (wall thickness of 186 cm) is about 19%, third test layer (wall thickness of 224 cm) is about 17%, fourth the test layer (wall thickness of 263 cm) is about 14%, fifth test layer (wall thickness of 300 cm) is about 12%, the back surface is about 17%; the greenhouse heat transfer to the outside from low to high in the enhancement, therefore, insulation measures should be strengthened with. 4. build the model of solar greenhouse wall temperature field based on finite element analysis software ANSYS to build a computing model for the solar greenhouse wall temperature field of the wall to measured temperature as degrees of freedom constraint imposed on the model boundary, the steady-state heat transfer method, simulated cloudy sunny conditions at different wall temperature change, and the simulation data and the measured data were compared, results showed that die
【學位授予單位】：山東農業(yè)大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：S625.1

【參考文獻】

相關期刊論文 前10條

1 韓順瓊;;關于我國設施農業(yè)發(fā)展現(xiàn)狀與對策的幾點思考[J];農業(yè)與技術;2016年24期

2 馬承偉;姜宜琛;程杰宇;趙淑梅;夏楠;王平智;陽萍;;日光溫室鋼管屋架管網水循環(huán)集放熱系統(tǒng)的性能分析與試驗[J];農業(yè)工程學報;2016年21期

3 蔣自鵬;鐵生年;;芒硝基相變材料性能及其在簡易溫室中升溫效果試驗[J];農業(yè)工程學報;2016年20期

4 王樹忠;陳殿奎;李新旭;高麗紅;張福墁;張振賢;;北京現(xiàn)代化大型連棟溫室發(fā)展的回顧、現(xiàn)狀與展望[J];中國蔬菜;2016年09期

5 郭建業(yè);秦貴;張艷紅;劉曉明;;日光溫室水循環(huán)增溫蓄熱系統(tǒng)應用效果研究[J];中國蔬菜;2016年09期

6 王宇欣;劉爽;王平智;時光營;;溫室蓄熱微膠囊相變材料制備篩選與性能表征[J];農業(yè)機械學報;2016年09期

7 周瑩;;不同保溫墻體對日光溫室熱環(huán)境的影響[J];湖北農業(yè)科學;2016年13期

8 王宇欣;劉爽;王平智;時光營;;日光溫室根區(qū)熱環(huán)境相變調控系統(tǒng)設計與性能試驗[J];農業(yè)機械學報;2016年08期

9 李天來;;我國設施蔬菜科技與產業(yè)發(fā)展現(xiàn)狀及趨勢[J];中國農村科技;2016年05期

10 賀冬仙;;日本人工光型植物工廠技術進展與典型案例[J];農業(yè)工程技術;2016年13期

相關博士學位論文 前3條

1 張志錄;下沉式日光溫室土質墻體傳熱特性的研究[D];河南農業(yè)大學;2012年

2 張勇;西北日光溫室傳熱學簡化模型構建及溫光高效新結構初探[D];西北農林科技大學;2012年

3 李小芳;日光溫室的熱環(huán)境數(shù)學模擬及其結構優(yōu)化[D];中國農業(yè)大學;2005年

相關碩士學位論文 前10條

1 張欣;日光溫室相變材料墻板蓄/放熱過程數(shù)值模擬研究[D];西北農林科技大學;2016年

2 壽先方;圍護結構傳熱系數(shù)現(xiàn)場檢測及熱量傳遞過程分析[D];東華大學;2015年

3 楊小龍;磚苯復合墻體日光溫室熱環(huán)境測試與模擬[D];西北農林科技大學;2014年

4 韓麗蓉;相變蓄熱材料十水硫酸鈉的改性及應用研究[D];西北農林科技大學;2014年

5 宋丹;日光溫室土質墻體研究及溫度環(huán)境模擬[D];西北農林科技大學;2013年

6 馬江偉;日光溫室無機相變蓄熱砌塊的制備及性能研究[D];西北農林科技大學;2013年

7 姚軒;超低能耗日光溫室保溫性能及其節(jié)能效果研究[D];太原理工大學;2011年

8 郭靖;外掛型相變材料日光溫室的蓄熱效果研究[D];西北農林科技大學;2011年

9 劉在民;節(jié)能日光溫室溫光性能優(yōu)化及其應用效果研究[D];東北農業(yè)大學;2007年

10 陳翠英;墻體的蓄放熱特性對室內熱環(huán)境調節(jié)作用的研究[D];大連理工大學;2006年

，

本文編號：1340035